1 //===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code to emit Stmt nodes as LLVM code.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "CGDebugInfo.h"
14 #include "CGOpenMPRuntime.h"
15 #include "CodeGenFunction.h"
16 #include "CodeGenModule.h"
17 #include "TargetInfo.h"
18 #include "clang/AST/Attr.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/Stmt.h"
21 #include "clang/AST/StmtVisitor.h"
22 #include "clang/Basic/Builtins.h"
23 #include "clang/Basic/DiagnosticSema.h"
24 #include "clang/Basic/PrettyStackTrace.h"
25 #include "clang/Basic/SourceManager.h"
26 #include "clang/Basic/TargetInfo.h"
27 #include "llvm/ADT/ArrayRef.h"
28 #include "llvm/ADT/DenseMap.h"
29 #include "llvm/ADT/SmallSet.h"
30 #include "llvm/ADT/StringExtras.h"
31 #include "llvm/IR/Assumptions.h"
32 #include "llvm/IR/DataLayout.h"
33 #include "llvm/IR/InlineAsm.h"
34 #include "llvm/IR/Intrinsics.h"
35 #include "llvm/IR/MDBuilder.h"
36 #include "llvm/Support/SaveAndRestore.h"
37 #include <optional>
38
39 using namespace clang;
40 using namespace CodeGen;
41
42 //===----------------------------------------------------------------------===//
43 // Statement Emission
44 //===----------------------------------------------------------------------===//
45
EmitStopPoint(const Stmt * S)46 void CodeGenFunction::EmitStopPoint(const Stmt *S) {
47 if (CGDebugInfo *DI = getDebugInfo()) {
48 SourceLocation Loc;
49 Loc = S->getBeginLoc();
50 DI->EmitLocation(Builder, Loc);
51
52 LastStopPoint = Loc;
53 }
54 }
55
EmitStmt(const Stmt * S,ArrayRef<const Attr * > Attrs)56 void CodeGenFunction::EmitStmt(const Stmt *S, ArrayRef<const Attr *> Attrs) {
57 assert(S && "Null statement?");
58 PGO.setCurrentStmt(S);
59
60 // These statements have their own debug info handling.
61 if (EmitSimpleStmt(S, Attrs))
62 return;
63
64 // Check if we are generating unreachable code.
65 if (!HaveInsertPoint()) {
66 // If so, and the statement doesn't contain a label, then we do not need to
67 // generate actual code. This is safe because (1) the current point is
68 // unreachable, so we don't need to execute the code, and (2) we've already
69 // handled the statements which update internal data structures (like the
70 // local variable map) which could be used by subsequent statements.
71 if (!ContainsLabel(S)) {
72 // Verify that any decl statements were handled as simple, they may be in
73 // scope of subsequent reachable statements.
74 assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
75 return;
76 }
77
78 // Otherwise, make a new block to hold the code.
79 EnsureInsertPoint();
80 }
81
82 // Generate a stoppoint if we are emitting debug info.
83 EmitStopPoint(S);
84
85 // Ignore all OpenMP directives except for simd if OpenMP with Simd is
86 // enabled.
87 if (getLangOpts().OpenMP && getLangOpts().OpenMPSimd) {
88 if (const auto *D = dyn_cast<OMPExecutableDirective>(S)) {
89 EmitSimpleOMPExecutableDirective(*D);
90 return;
91 }
92 }
93
94 switch (S->getStmtClass()) {
95 case Stmt::NoStmtClass:
96 case Stmt::CXXCatchStmtClass:
97 case Stmt::SEHExceptStmtClass:
98 case Stmt::SEHFinallyStmtClass:
99 case Stmt::MSDependentExistsStmtClass:
100 llvm_unreachable("invalid statement class to emit generically");
101 case Stmt::NullStmtClass:
102 case Stmt::CompoundStmtClass:
103 case Stmt::DeclStmtClass:
104 case Stmt::LabelStmtClass:
105 case Stmt::AttributedStmtClass:
106 case Stmt::GotoStmtClass:
107 case Stmt::BreakStmtClass:
108 case Stmt::ContinueStmtClass:
109 case Stmt::DefaultStmtClass:
110 case Stmt::CaseStmtClass:
111 case Stmt::SEHLeaveStmtClass:
112 llvm_unreachable("should have emitted these statements as simple");
113
114 #define STMT(Type, Base)
115 #define ABSTRACT_STMT(Op)
116 #define EXPR(Type, Base) \
117 case Stmt::Type##Class:
118 #include "clang/AST/StmtNodes.inc"
119 {
120 // Remember the block we came in on.
121 llvm::BasicBlock *incoming = Builder.GetInsertBlock();
122 assert(incoming && "expression emission must have an insertion point");
123
124 EmitIgnoredExpr(cast<Expr>(S));
125
126 llvm::BasicBlock *outgoing = Builder.GetInsertBlock();
127 assert(outgoing && "expression emission cleared block!");
128
129 // The expression emitters assume (reasonably!) that the insertion
130 // point is always set. To maintain that, the call-emission code
131 // for noreturn functions has to enter a new block with no
132 // predecessors. We want to kill that block and mark the current
133 // insertion point unreachable in the common case of a call like
134 // "exit();". Since expression emission doesn't otherwise create
135 // blocks with no predecessors, we can just test for that.
136 // However, we must be careful not to do this to our incoming
137 // block, because *statement* emission does sometimes create
138 // reachable blocks which will have no predecessors until later in
139 // the function. This occurs with, e.g., labels that are not
140 // reachable by fallthrough.
141 if (incoming != outgoing && outgoing->use_empty()) {
142 outgoing->eraseFromParent();
143 Builder.ClearInsertionPoint();
144 }
145 break;
146 }
147
148 case Stmt::IndirectGotoStmtClass:
149 EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;
150
151 case Stmt::IfStmtClass: EmitIfStmt(cast<IfStmt>(*S)); break;
152 case Stmt::WhileStmtClass: EmitWhileStmt(cast<WhileStmt>(*S), Attrs); break;
153 case Stmt::DoStmtClass: EmitDoStmt(cast<DoStmt>(*S), Attrs); break;
154 case Stmt::ForStmtClass: EmitForStmt(cast<ForStmt>(*S), Attrs); break;
155
156 case Stmt::ReturnStmtClass: EmitReturnStmt(cast<ReturnStmt>(*S)); break;
157
158 case Stmt::SwitchStmtClass: EmitSwitchStmt(cast<SwitchStmt>(*S)); break;
159 case Stmt::GCCAsmStmtClass: // Intentional fall-through.
160 case Stmt::MSAsmStmtClass: EmitAsmStmt(cast<AsmStmt>(*S)); break;
161 case Stmt::CoroutineBodyStmtClass:
162 EmitCoroutineBody(cast<CoroutineBodyStmt>(*S));
163 break;
164 case Stmt::CoreturnStmtClass:
165 EmitCoreturnStmt(cast<CoreturnStmt>(*S));
166 break;
167 case Stmt::CapturedStmtClass: {
168 const CapturedStmt *CS = cast<CapturedStmt>(S);
169 EmitCapturedStmt(*CS, CS->getCapturedRegionKind());
170 }
171 break;
172 case Stmt::ObjCAtTryStmtClass:
173 EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
174 break;
175 case Stmt::ObjCAtCatchStmtClass:
176 llvm_unreachable(
177 "@catch statements should be handled by EmitObjCAtTryStmt");
178 case Stmt::ObjCAtFinallyStmtClass:
179 llvm_unreachable(
180 "@finally statements should be handled by EmitObjCAtTryStmt");
181 case Stmt::ObjCAtThrowStmtClass:
182 EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S));
183 break;
184 case Stmt::ObjCAtSynchronizedStmtClass:
185 EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S));
186 break;
187 case Stmt::ObjCForCollectionStmtClass:
188 EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S));
189 break;
190 case Stmt::ObjCAutoreleasePoolStmtClass:
191 EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S));
192 break;
193
194 case Stmt::CXXTryStmtClass:
195 EmitCXXTryStmt(cast<CXXTryStmt>(*S));
196 break;
197 case Stmt::CXXForRangeStmtClass:
198 EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S), Attrs);
199 break;
200 case Stmt::SEHTryStmtClass:
201 EmitSEHTryStmt(cast<SEHTryStmt>(*S));
202 break;
203 case Stmt::OMPMetaDirectiveClass:
204 EmitOMPMetaDirective(cast<OMPMetaDirective>(*S));
205 break;
206 case Stmt::OMPCanonicalLoopClass:
207 EmitOMPCanonicalLoop(cast<OMPCanonicalLoop>(S));
208 break;
209 case Stmt::OMPParallelDirectiveClass:
210 EmitOMPParallelDirective(cast<OMPParallelDirective>(*S));
211 break;
212 case Stmt::OMPSimdDirectiveClass:
213 EmitOMPSimdDirective(cast<OMPSimdDirective>(*S));
214 break;
215 case Stmt::OMPTileDirectiveClass:
216 EmitOMPTileDirective(cast<OMPTileDirective>(*S));
217 break;
218 case Stmt::OMPUnrollDirectiveClass:
219 EmitOMPUnrollDirective(cast<OMPUnrollDirective>(*S));
220 break;
221 case Stmt::OMPForDirectiveClass:
222 EmitOMPForDirective(cast<OMPForDirective>(*S));
223 break;
224 case Stmt::OMPForSimdDirectiveClass:
225 EmitOMPForSimdDirective(cast<OMPForSimdDirective>(*S));
226 break;
227 case Stmt::OMPSectionsDirectiveClass:
228 EmitOMPSectionsDirective(cast<OMPSectionsDirective>(*S));
229 break;
230 case Stmt::OMPSectionDirectiveClass:
231 EmitOMPSectionDirective(cast<OMPSectionDirective>(*S));
232 break;
233 case Stmt::OMPSingleDirectiveClass:
234 EmitOMPSingleDirective(cast<OMPSingleDirective>(*S));
235 break;
236 case Stmt::OMPMasterDirectiveClass:
237 EmitOMPMasterDirective(cast<OMPMasterDirective>(*S));
238 break;
239 case Stmt::OMPCriticalDirectiveClass:
240 EmitOMPCriticalDirective(cast<OMPCriticalDirective>(*S));
241 break;
242 case Stmt::OMPParallelForDirectiveClass:
243 EmitOMPParallelForDirective(cast<OMPParallelForDirective>(*S));
244 break;
245 case Stmt::OMPParallelForSimdDirectiveClass:
246 EmitOMPParallelForSimdDirective(cast<OMPParallelForSimdDirective>(*S));
247 break;
248 case Stmt::OMPParallelMasterDirectiveClass:
249 EmitOMPParallelMasterDirective(cast<OMPParallelMasterDirective>(*S));
250 break;
251 case Stmt::OMPParallelSectionsDirectiveClass:
252 EmitOMPParallelSectionsDirective(cast<OMPParallelSectionsDirective>(*S));
253 break;
254 case Stmt::OMPTaskDirectiveClass:
255 EmitOMPTaskDirective(cast<OMPTaskDirective>(*S));
256 break;
257 case Stmt::OMPTaskyieldDirectiveClass:
258 EmitOMPTaskyieldDirective(cast<OMPTaskyieldDirective>(*S));
259 break;
260 case Stmt::OMPErrorDirectiveClass:
261 EmitOMPErrorDirective(cast<OMPErrorDirective>(*S));
262 break;
263 case Stmt::OMPBarrierDirectiveClass:
264 EmitOMPBarrierDirective(cast<OMPBarrierDirective>(*S));
265 break;
266 case Stmt::OMPTaskwaitDirectiveClass:
267 EmitOMPTaskwaitDirective(cast<OMPTaskwaitDirective>(*S));
268 break;
269 case Stmt::OMPTaskgroupDirectiveClass:
270 EmitOMPTaskgroupDirective(cast<OMPTaskgroupDirective>(*S));
271 break;
272 case Stmt::OMPFlushDirectiveClass:
273 EmitOMPFlushDirective(cast<OMPFlushDirective>(*S));
274 break;
275 case Stmt::OMPDepobjDirectiveClass:
276 EmitOMPDepobjDirective(cast<OMPDepobjDirective>(*S));
277 break;
278 case Stmt::OMPScanDirectiveClass:
279 EmitOMPScanDirective(cast<OMPScanDirective>(*S));
280 break;
281 case Stmt::OMPOrderedDirectiveClass:
282 EmitOMPOrderedDirective(cast<OMPOrderedDirective>(*S));
283 break;
284 case Stmt::OMPAtomicDirectiveClass:
285 EmitOMPAtomicDirective(cast<OMPAtomicDirective>(*S));
286 break;
287 case Stmt::OMPTargetDirectiveClass:
288 EmitOMPTargetDirective(cast<OMPTargetDirective>(*S));
289 break;
290 case Stmt::OMPTeamsDirectiveClass:
291 EmitOMPTeamsDirective(cast<OMPTeamsDirective>(*S));
292 break;
293 case Stmt::OMPCancellationPointDirectiveClass:
294 EmitOMPCancellationPointDirective(cast<OMPCancellationPointDirective>(*S));
295 break;
296 case Stmt::OMPCancelDirectiveClass:
297 EmitOMPCancelDirective(cast<OMPCancelDirective>(*S));
298 break;
299 case Stmt::OMPTargetDataDirectiveClass:
300 EmitOMPTargetDataDirective(cast<OMPTargetDataDirective>(*S));
301 break;
302 case Stmt::OMPTargetEnterDataDirectiveClass:
303 EmitOMPTargetEnterDataDirective(cast<OMPTargetEnterDataDirective>(*S));
304 break;
305 case Stmt::OMPTargetExitDataDirectiveClass:
306 EmitOMPTargetExitDataDirective(cast<OMPTargetExitDataDirective>(*S));
307 break;
308 case Stmt::OMPTargetParallelDirectiveClass:
309 EmitOMPTargetParallelDirective(cast<OMPTargetParallelDirective>(*S));
310 break;
311 case Stmt::OMPTargetParallelForDirectiveClass:
312 EmitOMPTargetParallelForDirective(cast<OMPTargetParallelForDirective>(*S));
313 break;
314 case Stmt::OMPTaskLoopDirectiveClass:
315 EmitOMPTaskLoopDirective(cast<OMPTaskLoopDirective>(*S));
316 break;
317 case Stmt::OMPTaskLoopSimdDirectiveClass:
318 EmitOMPTaskLoopSimdDirective(cast<OMPTaskLoopSimdDirective>(*S));
319 break;
320 case Stmt::OMPMasterTaskLoopDirectiveClass:
321 EmitOMPMasterTaskLoopDirective(cast<OMPMasterTaskLoopDirective>(*S));
322 break;
323 case Stmt::OMPMaskedTaskLoopDirectiveClass:
324 llvm_unreachable("masked taskloop directive not supported yet.");
325 break;
326 case Stmt::OMPMasterTaskLoopSimdDirectiveClass:
327 EmitOMPMasterTaskLoopSimdDirective(
328 cast<OMPMasterTaskLoopSimdDirective>(*S));
329 break;
330 case Stmt::OMPMaskedTaskLoopSimdDirectiveClass:
331 llvm_unreachable("masked taskloop simd directive not supported yet.");
332 break;
333 case Stmt::OMPParallelMasterTaskLoopDirectiveClass:
334 EmitOMPParallelMasterTaskLoopDirective(
335 cast<OMPParallelMasterTaskLoopDirective>(*S));
336 break;
337 case Stmt::OMPParallelMaskedTaskLoopDirectiveClass:
338 llvm_unreachable("parallel masked taskloop directive not supported yet.");
339 break;
340 case Stmt::OMPParallelMasterTaskLoopSimdDirectiveClass:
341 EmitOMPParallelMasterTaskLoopSimdDirective(
342 cast<OMPParallelMasterTaskLoopSimdDirective>(*S));
343 break;
344 case Stmt::OMPParallelMaskedTaskLoopSimdDirectiveClass:
345 llvm_unreachable(
346 "parallel masked taskloop simd directive not supported yet.");
347 break;
348 case Stmt::OMPDistributeDirectiveClass:
349 EmitOMPDistributeDirective(cast<OMPDistributeDirective>(*S));
350 break;
351 case Stmt::OMPTargetUpdateDirectiveClass:
352 EmitOMPTargetUpdateDirective(cast<OMPTargetUpdateDirective>(*S));
353 break;
354 case Stmt::OMPDistributeParallelForDirectiveClass:
355 EmitOMPDistributeParallelForDirective(
356 cast<OMPDistributeParallelForDirective>(*S));
357 break;
358 case Stmt::OMPDistributeParallelForSimdDirectiveClass:
359 EmitOMPDistributeParallelForSimdDirective(
360 cast<OMPDistributeParallelForSimdDirective>(*S));
361 break;
362 case Stmt::OMPDistributeSimdDirectiveClass:
363 EmitOMPDistributeSimdDirective(cast<OMPDistributeSimdDirective>(*S));
364 break;
365 case Stmt::OMPTargetParallelForSimdDirectiveClass:
366 EmitOMPTargetParallelForSimdDirective(
367 cast<OMPTargetParallelForSimdDirective>(*S));
368 break;
369 case Stmt::OMPTargetSimdDirectiveClass:
370 EmitOMPTargetSimdDirective(cast<OMPTargetSimdDirective>(*S));
371 break;
372 case Stmt::OMPTeamsDistributeDirectiveClass:
373 EmitOMPTeamsDistributeDirective(cast<OMPTeamsDistributeDirective>(*S));
374 break;
375 case Stmt::OMPTeamsDistributeSimdDirectiveClass:
376 EmitOMPTeamsDistributeSimdDirective(
377 cast<OMPTeamsDistributeSimdDirective>(*S));
378 break;
379 case Stmt::OMPTeamsDistributeParallelForSimdDirectiveClass:
380 EmitOMPTeamsDistributeParallelForSimdDirective(
381 cast<OMPTeamsDistributeParallelForSimdDirective>(*S));
382 break;
383 case Stmt::OMPTeamsDistributeParallelForDirectiveClass:
384 EmitOMPTeamsDistributeParallelForDirective(
385 cast<OMPTeamsDistributeParallelForDirective>(*S));
386 break;
387 case Stmt::OMPTargetTeamsDirectiveClass:
388 EmitOMPTargetTeamsDirective(cast<OMPTargetTeamsDirective>(*S));
389 break;
390 case Stmt::OMPTargetTeamsDistributeDirectiveClass:
391 EmitOMPTargetTeamsDistributeDirective(
392 cast<OMPTargetTeamsDistributeDirective>(*S));
393 break;
394 case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass:
395 EmitOMPTargetTeamsDistributeParallelForDirective(
396 cast<OMPTargetTeamsDistributeParallelForDirective>(*S));
397 break;
398 case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass:
399 EmitOMPTargetTeamsDistributeParallelForSimdDirective(
400 cast<OMPTargetTeamsDistributeParallelForSimdDirective>(*S));
401 break;
402 case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
403 EmitOMPTargetTeamsDistributeSimdDirective(
404 cast<OMPTargetTeamsDistributeSimdDirective>(*S));
405 break;
406 case Stmt::OMPInteropDirectiveClass:
407 EmitOMPInteropDirective(cast<OMPInteropDirective>(*S));
408 break;
409 case Stmt::OMPDispatchDirectiveClass:
410 CGM.ErrorUnsupported(S, "OpenMP dispatch directive");
411 break;
412 case Stmt::OMPScopeDirectiveClass:
413 llvm_unreachable("scope not supported with FE outlining");
414 case Stmt::OMPMaskedDirectiveClass:
415 EmitOMPMaskedDirective(cast<OMPMaskedDirective>(*S));
416 break;
417 case Stmt::OMPGenericLoopDirectiveClass:
418 EmitOMPGenericLoopDirective(cast<OMPGenericLoopDirective>(*S));
419 break;
420 case Stmt::OMPTeamsGenericLoopDirectiveClass:
421 EmitOMPTeamsGenericLoopDirective(cast<OMPTeamsGenericLoopDirective>(*S));
422 break;
423 case Stmt::OMPTargetTeamsGenericLoopDirectiveClass:
424 EmitOMPTargetTeamsGenericLoopDirective(
425 cast<OMPTargetTeamsGenericLoopDirective>(*S));
426 break;
427 case Stmt::OMPParallelGenericLoopDirectiveClass:
428 EmitOMPParallelGenericLoopDirective(
429 cast<OMPParallelGenericLoopDirective>(*S));
430 break;
431 case Stmt::OMPTargetParallelGenericLoopDirectiveClass:
432 EmitOMPTargetParallelGenericLoopDirective(
433 cast<OMPTargetParallelGenericLoopDirective>(*S));
434 break;
435 case Stmt::OMPParallelMaskedDirectiveClass:
436 EmitOMPParallelMaskedDirective(cast<OMPParallelMaskedDirective>(*S));
437 break;
438 }
439 }
440
EmitSimpleStmt(const Stmt * S,ArrayRef<const Attr * > Attrs)441 bool CodeGenFunction::EmitSimpleStmt(const Stmt *S,
442 ArrayRef<const Attr *> Attrs) {
443 switch (S->getStmtClass()) {
444 default:
445 return false;
446 case Stmt::NullStmtClass:
447 break;
448 case Stmt::CompoundStmtClass:
449 EmitCompoundStmt(cast<CompoundStmt>(*S));
450 break;
451 case Stmt::DeclStmtClass:
452 EmitDeclStmt(cast<DeclStmt>(*S));
453 break;
454 case Stmt::LabelStmtClass:
455 EmitLabelStmt(cast<LabelStmt>(*S));
456 break;
457 case Stmt::AttributedStmtClass:
458 EmitAttributedStmt(cast<AttributedStmt>(*S));
459 break;
460 case Stmt::GotoStmtClass:
461 EmitGotoStmt(cast<GotoStmt>(*S));
462 break;
463 case Stmt::BreakStmtClass:
464 EmitBreakStmt(cast<BreakStmt>(*S));
465 break;
466 case Stmt::ContinueStmtClass:
467 EmitContinueStmt(cast<ContinueStmt>(*S));
468 break;
469 case Stmt::DefaultStmtClass:
470 EmitDefaultStmt(cast<DefaultStmt>(*S), Attrs);
471 break;
472 case Stmt::CaseStmtClass:
473 EmitCaseStmt(cast<CaseStmt>(*S), Attrs);
474 break;
475 case Stmt::SEHLeaveStmtClass:
476 EmitSEHLeaveStmt(cast<SEHLeaveStmt>(*S));
477 break;
478 }
479 return true;
480 }
481
482 /// EmitCompoundStmt - Emit a compound statement {..} node. If GetLast is true,
483 /// this captures the expression result of the last sub-statement and returns it
484 /// (for use by the statement expression extension).
EmitCompoundStmt(const CompoundStmt & S,bool GetLast,AggValueSlot AggSlot)485 Address CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast,
486 AggValueSlot AggSlot) {
487 PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(),
488 "LLVM IR generation of compound statement ('{}')");
489
490 // Keep track of the current cleanup stack depth, including debug scopes.
491 LexicalScope Scope(*this, S.getSourceRange());
492
493 return EmitCompoundStmtWithoutScope(S, GetLast, AggSlot);
494 }
495
496 Address
EmitCompoundStmtWithoutScope(const CompoundStmt & S,bool GetLast,AggValueSlot AggSlot)497 CodeGenFunction::EmitCompoundStmtWithoutScope(const CompoundStmt &S,
498 bool GetLast,
499 AggValueSlot AggSlot) {
500
501 const Stmt *ExprResult = S.getStmtExprResult();
502 assert((!GetLast || (GetLast && ExprResult)) &&
503 "If GetLast is true then the CompoundStmt must have a StmtExprResult");
504
505 Address RetAlloca = Address::invalid();
506
507 for (auto *CurStmt : S.body()) {
508 if (GetLast && ExprResult == CurStmt) {
509 // We have to special case labels here. They are statements, but when put
510 // at the end of a statement expression, they yield the value of their
511 // subexpression. Handle this by walking through all labels we encounter,
512 // emitting them before we evaluate the subexpr.
513 // Similar issues arise for attributed statements.
514 while (!isa<Expr>(ExprResult)) {
515 if (const auto *LS = dyn_cast<LabelStmt>(ExprResult)) {
516 EmitLabel(LS->getDecl());
517 ExprResult = LS->getSubStmt();
518 } else if (const auto *AS = dyn_cast<AttributedStmt>(ExprResult)) {
519 // FIXME: Update this if we ever have attributes that affect the
520 // semantics of an expression.
521 ExprResult = AS->getSubStmt();
522 } else {
523 llvm_unreachable("unknown value statement");
524 }
525 }
526
527 EnsureInsertPoint();
528
529 const Expr *E = cast<Expr>(ExprResult);
530 QualType ExprTy = E->getType();
531 if (hasAggregateEvaluationKind(ExprTy)) {
532 EmitAggExpr(E, AggSlot);
533 } else {
534 // We can't return an RValue here because there might be cleanups at
535 // the end of the StmtExpr. Because of that, we have to emit the result
536 // here into a temporary alloca.
537 RetAlloca = CreateMemTemp(ExprTy);
538 EmitAnyExprToMem(E, RetAlloca, Qualifiers(),
539 /*IsInit*/ false);
540 }
541 } else {
542 EmitStmt(CurStmt);
543 }
544 }
545
546 return RetAlloca;
547 }
548
SimplifyForwardingBlocks(llvm::BasicBlock * BB)549 void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) {
550 llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator());
551
552 // If there is a cleanup stack, then we it isn't worth trying to
553 // simplify this block (we would need to remove it from the scope map
554 // and cleanup entry).
555 if (!EHStack.empty())
556 return;
557
558 // Can only simplify direct branches.
559 if (!BI || !BI->isUnconditional())
560 return;
561
562 // Can only simplify empty blocks.
563 if (BI->getIterator() != BB->begin())
564 return;
565
566 BB->replaceAllUsesWith(BI->getSuccessor(0));
567 BI->eraseFromParent();
568 BB->eraseFromParent();
569 }
570
EmitBlock(llvm::BasicBlock * BB,bool IsFinished)571 void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) {
572 llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
573
574 // Fall out of the current block (if necessary).
575 EmitBranch(BB);
576
577 if (IsFinished && BB->use_empty()) {
578 delete BB;
579 return;
580 }
581
582 // Place the block after the current block, if possible, or else at
583 // the end of the function.
584 if (CurBB && CurBB->getParent())
585 CurFn->insert(std::next(CurBB->getIterator()), BB);
586 else
587 CurFn->insert(CurFn->end(), BB);
588 Builder.SetInsertPoint(BB);
589 }
590
EmitBranch(llvm::BasicBlock * Target)591 void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
592 // Emit a branch from the current block to the target one if this
593 // was a real block. If this was just a fall-through block after a
594 // terminator, don't emit it.
595 llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
596
597 if (!CurBB || CurBB->getTerminator()) {
598 // If there is no insert point or the previous block is already
599 // terminated, don't touch it.
600 } else {
601 // Otherwise, create a fall-through branch.
602 Builder.CreateBr(Target);
603 }
604
605 Builder.ClearInsertionPoint();
606 }
607
EmitBlockAfterUses(llvm::BasicBlock * block)608 void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) {
609 bool inserted = false;
610 for (llvm::User *u : block->users()) {
611 if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(u)) {
612 CurFn->insert(std::next(insn->getParent()->getIterator()), block);
613 inserted = true;
614 break;
615 }
616 }
617
618 if (!inserted)
619 CurFn->insert(CurFn->end(), block);
620
621 Builder.SetInsertPoint(block);
622 }
623
624 CodeGenFunction::JumpDest
getJumpDestForLabel(const LabelDecl * D)625 CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
626 JumpDest &Dest = LabelMap[D];
627 if (Dest.isValid()) return Dest;
628
629 // Create, but don't insert, the new block.
630 Dest = JumpDest(createBasicBlock(D->getName()),
631 EHScopeStack::stable_iterator::invalid(),
632 NextCleanupDestIndex++);
633 return Dest;
634 }
635
EmitLabel(const LabelDecl * D)636 void CodeGenFunction::EmitLabel(const LabelDecl *D) {
637 // Add this label to the current lexical scope if we're within any
638 // normal cleanups. Jumps "in" to this label --- when permitted by
639 // the language --- may need to be routed around such cleanups.
640 if (EHStack.hasNormalCleanups() && CurLexicalScope)
641 CurLexicalScope->addLabel(D);
642
643 JumpDest &Dest = LabelMap[D];
644
645 // If we didn't need a forward reference to this label, just go
646 // ahead and create a destination at the current scope.
647 if (!Dest.isValid()) {
648 Dest = getJumpDestInCurrentScope(D->getName());
649
650 // Otherwise, we need to give this label a target depth and remove
651 // it from the branch-fixups list.
652 } else {
653 assert(!Dest.getScopeDepth().isValid() && "already emitted label!");
654 Dest.setScopeDepth(EHStack.stable_begin());
655 ResolveBranchFixups(Dest.getBlock());
656 }
657
658 EmitBlock(Dest.getBlock());
659
660 // Emit debug info for labels.
661 if (CGDebugInfo *DI = getDebugInfo()) {
662 if (CGM.getCodeGenOpts().hasReducedDebugInfo()) {
663 DI->setLocation(D->getLocation());
664 DI->EmitLabel(D, Builder);
665 }
666 }
667
668 incrementProfileCounter(D->getStmt());
669 }
670
671 /// Change the cleanup scope of the labels in this lexical scope to
672 /// match the scope of the enclosing context.
rescopeLabels()673 void CodeGenFunction::LexicalScope::rescopeLabels() {
674 assert(!Labels.empty());
675 EHScopeStack::stable_iterator innermostScope
676 = CGF.EHStack.getInnermostNormalCleanup();
677
678 // Change the scope depth of all the labels.
679 for (SmallVectorImpl<const LabelDecl*>::const_iterator
680 i = Labels.begin(), e = Labels.end(); i != e; ++i) {
681 assert(CGF.LabelMap.count(*i));
682 JumpDest &dest = CGF.LabelMap.find(*i)->second;
683 assert(dest.getScopeDepth().isValid());
684 assert(innermostScope.encloses(dest.getScopeDepth()));
685 dest.setScopeDepth(innermostScope);
686 }
687
688 // Reparent the labels if the new scope also has cleanups.
689 if (innermostScope != EHScopeStack::stable_end() && ParentScope) {
690 ParentScope->Labels.append(Labels.begin(), Labels.end());
691 }
692 }
693
694
EmitLabelStmt(const LabelStmt & S)695 void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
696 EmitLabel(S.getDecl());
697
698 // IsEHa - emit eha.scope.begin if it's a side entry of a scope
699 if (getLangOpts().EHAsynch && S.isSideEntry())
700 EmitSehCppScopeBegin();
701
702 EmitStmt(S.getSubStmt());
703 }
704
EmitAttributedStmt(const AttributedStmt & S)705 void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
706 bool nomerge = false;
707 bool noinline = false;
708 bool alwaysinline = false;
709 const CallExpr *musttail = nullptr;
710
711 for (const auto *A : S.getAttrs()) {
712 switch (A->getKind()) {
713 default:
714 break;
715 case attr::NoMerge:
716 nomerge = true;
717 break;
718 case attr::NoInline:
719 noinline = true;
720 break;
721 case attr::AlwaysInline:
722 alwaysinline = true;
723 break;
724 case attr::MustTail:
725 const Stmt *Sub = S.getSubStmt();
726 const ReturnStmt *R = cast<ReturnStmt>(Sub);
727 musttail = cast<CallExpr>(R->getRetValue()->IgnoreParens());
728 break;
729 }
730 }
731 SaveAndRestore save_nomerge(InNoMergeAttributedStmt, nomerge);
732 SaveAndRestore save_noinline(InNoInlineAttributedStmt, noinline);
733 SaveAndRestore save_alwaysinline(InAlwaysInlineAttributedStmt, alwaysinline);
734 SaveAndRestore save_musttail(MustTailCall, musttail);
735 EmitStmt(S.getSubStmt(), S.getAttrs());
736 }
737
EmitGotoStmt(const GotoStmt & S)738 void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
739 // If this code is reachable then emit a stop point (if generating
740 // debug info). We have to do this ourselves because we are on the
741 // "simple" statement path.
742 if (HaveInsertPoint())
743 EmitStopPoint(&S);
744
745 EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
746 }
747
748
EmitIndirectGotoStmt(const IndirectGotoStmt & S)749 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
750 if (const LabelDecl *Target = S.getConstantTarget()) {
751 EmitBranchThroughCleanup(getJumpDestForLabel(Target));
752 return;
753 }
754
755 // Ensure that we have an i8* for our PHI node.
756 llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
757 Int8PtrTy, "addr");
758 llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
759
760 // Get the basic block for the indirect goto.
761 llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
762
763 // The first instruction in the block has to be the PHI for the switch dest,
764 // add an entry for this branch.
765 cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
766
767 EmitBranch(IndGotoBB);
768 }
769
EmitIfStmt(const IfStmt & S)770 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
771 // The else branch of a consteval if statement is always the only branch that
772 // can be runtime evaluated.
773 if (S.isConsteval()) {
774 const Stmt *Executed = S.isNegatedConsteval() ? S.getThen() : S.getElse();
775 if (Executed) {
776 RunCleanupsScope ExecutedScope(*this);
777 EmitStmt(Executed);
778 }
779 return;
780 }
781
782 // C99 6.8.4.1: The first substatement is executed if the expression compares
783 // unequal to 0. The condition must be a scalar type.
784 LexicalScope ConditionScope(*this, S.getCond()->getSourceRange());
785
786 if (S.getInit())
787 EmitStmt(S.getInit());
788
789 if (S.getConditionVariable())
790 EmitDecl(*S.getConditionVariable());
791
792 // If the condition constant folds and can be elided, try to avoid emitting
793 // the condition and the dead arm of the if/else.
794 bool CondConstant;
795 if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant,
796 S.isConstexpr())) {
797 // Figure out which block (then or else) is executed.
798 const Stmt *Executed = S.getThen();
799 const Stmt *Skipped = S.getElse();
800 if (!CondConstant) // Condition false?
801 std::swap(Executed, Skipped);
802
803 // If the skipped block has no labels in it, just emit the executed block.
804 // This avoids emitting dead code and simplifies the CFG substantially.
805 if (S.isConstexpr() || !ContainsLabel(Skipped)) {
806 if (CondConstant)
807 incrementProfileCounter(&S);
808 if (Executed) {
809 RunCleanupsScope ExecutedScope(*this);
810 EmitStmt(Executed);
811 }
812 return;
813 }
814 }
815
816 // Otherwise, the condition did not fold, or we couldn't elide it. Just emit
817 // the conditional branch.
818 llvm::BasicBlock *ThenBlock = createBasicBlock("if.then");
819 llvm::BasicBlock *ContBlock = createBasicBlock("if.end");
820 llvm::BasicBlock *ElseBlock = ContBlock;
821 if (S.getElse())
822 ElseBlock = createBasicBlock("if.else");
823
824 // Prefer the PGO based weights over the likelihood attribute.
825 // When the build isn't optimized the metadata isn't used, so don't generate
826 // it.
827 // Also, differentiate between disabled PGO and a never executed branch with
828 // PGO. Assuming PGO is in use:
829 // - we want to ignore the [[likely]] attribute if the branch is never
830 // executed,
831 // - assuming the profile is poor, preserving the attribute may still be
832 // beneficial.
833 // As an approximation, preserve the attribute only if both the branch and the
834 // parent context were not executed.
835 Stmt::Likelihood LH = Stmt::LH_None;
836 uint64_t ThenCount = getProfileCount(S.getThen());
837 if (!ThenCount && !getCurrentProfileCount() &&
838 CGM.getCodeGenOpts().OptimizationLevel)
839 LH = Stmt::getLikelihood(S.getThen(), S.getElse());
840
841 // When measuring MC/DC, always fully evaluate the condition up front using
842 // EvaluateExprAsBool() so that the test vector bitmap can be updated prior to
843 // executing the body of the if.then or if.else. This is useful for when
844 // there is a 'return' within the body, but this is particularly beneficial
845 // when one if-stmt is nested within another if-stmt so that all of the MC/DC
846 // updates are kept linear and consistent.
847 if (!CGM.getCodeGenOpts().MCDCCoverage)
848 EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock, ThenCount, LH);
849 else {
850 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
851 Builder.CreateCondBr(BoolCondVal, ThenBlock, ElseBlock);
852 }
853
854 // Emit the 'then' code.
855 EmitBlock(ThenBlock);
856 incrementProfileCounter(&S);
857 {
858 RunCleanupsScope ThenScope(*this);
859 EmitStmt(S.getThen());
860 }
861 EmitBranch(ContBlock);
862
863 // Emit the 'else' code if present.
864 if (const Stmt *Else = S.getElse()) {
865 {
866 // There is no need to emit line number for an unconditional branch.
867 auto NL = ApplyDebugLocation::CreateEmpty(*this);
868 EmitBlock(ElseBlock);
869 }
870 {
871 RunCleanupsScope ElseScope(*this);
872 EmitStmt(Else);
873 }
874 {
875 // There is no need to emit line number for an unconditional branch.
876 auto NL = ApplyDebugLocation::CreateEmpty(*this);
877 EmitBranch(ContBlock);
878 }
879 }
880
881 // Emit the continuation block for code after the if.
882 EmitBlock(ContBlock, true);
883 }
884
EmitWhileStmt(const WhileStmt & S,ArrayRef<const Attr * > WhileAttrs)885 void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
886 ArrayRef<const Attr *> WhileAttrs) {
887 // Emit the header for the loop, which will also become
888 // the continue target.
889 JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
890 EmitBlock(LoopHeader.getBlock());
891
892 // Create an exit block for when the condition fails, which will
893 // also become the break target.
894 JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
895
896 // Store the blocks to use for break and continue.
897 BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader));
898
899 // C++ [stmt.while]p2:
900 // When the condition of a while statement is a declaration, the
901 // scope of the variable that is declared extends from its point
902 // of declaration (3.3.2) to the end of the while statement.
903 // [...]
904 // The object created in a condition is destroyed and created
905 // with each iteration of the loop.
906 RunCleanupsScope ConditionScope(*this);
907
908 if (S.getConditionVariable())
909 EmitDecl(*S.getConditionVariable());
910
911 // Evaluate the conditional in the while header. C99 6.8.5.1: The
912 // evaluation of the controlling expression takes place before each
913 // execution of the loop body.
914 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
915
916 // while(1) is common, avoid extra exit blocks. Be sure
917 // to correctly handle break/continue though.
918 llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
919 bool CondIsConstInt = C != nullptr;
920 bool EmitBoolCondBranch = !CondIsConstInt || !C->isOne();
921 const SourceRange &R = S.getSourceRange();
922 LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(),
923 WhileAttrs, SourceLocToDebugLoc(R.getBegin()),
924 SourceLocToDebugLoc(R.getEnd()),
925 checkIfLoopMustProgress(CondIsConstInt));
926
927 // As long as the condition is true, go to the loop body.
928 llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
929 if (EmitBoolCondBranch) {
930 llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
931 if (ConditionScope.requiresCleanups())
932 ExitBlock = createBasicBlock("while.exit");
933 llvm::MDNode *Weights =
934 createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
935 if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
936 BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
937 BoolCondVal, Stmt::getLikelihood(S.getBody()));
938 Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, Weights);
939
940 if (ExitBlock != LoopExit.getBlock()) {
941 EmitBlock(ExitBlock);
942 EmitBranchThroughCleanup(LoopExit);
943 }
944 } else if (const Attr *A = Stmt::getLikelihoodAttr(S.getBody())) {
945 CGM.getDiags().Report(A->getLocation(),
946 diag::warn_attribute_has_no_effect_on_infinite_loop)
947 << A << A->getRange();
948 CGM.getDiags().Report(
949 S.getWhileLoc(),
950 diag::note_attribute_has_no_effect_on_infinite_loop_here)
951 << SourceRange(S.getWhileLoc(), S.getRParenLoc());
952 }
953
954 // Emit the loop body. We have to emit this in a cleanup scope
955 // because it might be a singleton DeclStmt.
956 {
957 RunCleanupsScope BodyScope(*this);
958 EmitBlock(LoopBody);
959 incrementProfileCounter(&S);
960 EmitStmt(S.getBody());
961 }
962
963 BreakContinueStack.pop_back();
964
965 // Immediately force cleanup.
966 ConditionScope.ForceCleanup();
967
968 EmitStopPoint(&S);
969 // Branch to the loop header again.
970 EmitBranch(LoopHeader.getBlock());
971
972 LoopStack.pop();
973
974 // Emit the exit block.
975 EmitBlock(LoopExit.getBlock(), true);
976
977 // The LoopHeader typically is just a branch if we skipped emitting
978 // a branch, try to erase it.
979 if (!EmitBoolCondBranch)
980 SimplifyForwardingBlocks(LoopHeader.getBlock());
981 }
982
EmitDoStmt(const DoStmt & S,ArrayRef<const Attr * > DoAttrs)983 void CodeGenFunction::EmitDoStmt(const DoStmt &S,
984 ArrayRef<const Attr *> DoAttrs) {
985 JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
986 JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
987
988 uint64_t ParentCount = getCurrentProfileCount();
989
990 // Store the blocks to use for break and continue.
991 BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond));
992
993 // Emit the body of the loop.
994 llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
995
996 EmitBlockWithFallThrough(LoopBody, &S);
997 {
998 RunCleanupsScope BodyScope(*this);
999 EmitStmt(S.getBody());
1000 }
1001
1002 EmitBlock(LoopCond.getBlock());
1003
1004 // C99 6.8.5.2: "The evaluation of the controlling expression takes place
1005 // after each execution of the loop body."
1006
1007 // Evaluate the conditional in the while header.
1008 // C99 6.8.5p2/p4: The first substatement is executed if the expression
1009 // compares unequal to 0. The condition must be a scalar type.
1010 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1011
1012 BreakContinueStack.pop_back();
1013
1014 // "do {} while (0)" is common in macros, avoid extra blocks. Be sure
1015 // to correctly handle break/continue though.
1016 llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
1017 bool CondIsConstInt = C;
1018 bool EmitBoolCondBranch = !C || !C->isZero();
1019
1020 const SourceRange &R = S.getSourceRange();
1021 LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
1022 SourceLocToDebugLoc(R.getBegin()),
1023 SourceLocToDebugLoc(R.getEnd()),
1024 checkIfLoopMustProgress(CondIsConstInt));
1025
1026 // As long as the condition is true, iterate the loop.
1027 if (EmitBoolCondBranch) {
1028 uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount;
1029 Builder.CreateCondBr(
1030 BoolCondVal, LoopBody, LoopExit.getBlock(),
1031 createProfileWeightsForLoop(S.getCond(), BackedgeCount));
1032 }
1033
1034 LoopStack.pop();
1035
1036 // Emit the exit block.
1037 EmitBlock(LoopExit.getBlock());
1038
1039 // The DoCond block typically is just a branch if we skipped
1040 // emitting a branch, try to erase it.
1041 if (!EmitBoolCondBranch)
1042 SimplifyForwardingBlocks(LoopCond.getBlock());
1043 }
1044
EmitForStmt(const ForStmt & S,ArrayRef<const Attr * > ForAttrs)1045 void CodeGenFunction::EmitForStmt(const ForStmt &S,
1046 ArrayRef<const Attr *> ForAttrs) {
1047 JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1048
1049 LexicalScope ForScope(*this, S.getSourceRange());
1050
1051 // Evaluate the first part before the loop.
1052 if (S.getInit())
1053 EmitStmt(S.getInit());
1054
1055 // Start the loop with a block that tests the condition.
1056 // If there's an increment, the continue scope will be overwritten
1057 // later.
1058 JumpDest CondDest = getJumpDestInCurrentScope("for.cond");
1059 llvm::BasicBlock *CondBlock = CondDest.getBlock();
1060 EmitBlock(CondBlock);
1061
1062 Expr::EvalResult Result;
1063 bool CondIsConstInt =
1064 !S.getCond() || S.getCond()->EvaluateAsInt(Result, getContext());
1065
1066 const SourceRange &R = S.getSourceRange();
1067 LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1068 SourceLocToDebugLoc(R.getBegin()),
1069 SourceLocToDebugLoc(R.getEnd()),
1070 checkIfLoopMustProgress(CondIsConstInt));
1071
1072 // Create a cleanup scope for the condition variable cleanups.
1073 LexicalScope ConditionScope(*this, S.getSourceRange());
1074
1075 // If the for loop doesn't have an increment we can just use the condition as
1076 // the continue block. Otherwise, if there is no condition variable, we can
1077 // form the continue block now. If there is a condition variable, we can't
1078 // form the continue block until after we've emitted the condition, because
1079 // the condition is in scope in the increment, but Sema's jump diagnostics
1080 // ensure that there are no continues from the condition variable that jump
1081 // to the loop increment.
1082 JumpDest Continue;
1083 if (!S.getInc())
1084 Continue = CondDest;
1085 else if (!S.getConditionVariable())
1086 Continue = getJumpDestInCurrentScope("for.inc");
1087 BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1088
1089 if (S.getCond()) {
1090 // If the for statement has a condition scope, emit the local variable
1091 // declaration.
1092 if (S.getConditionVariable()) {
1093 EmitDecl(*S.getConditionVariable());
1094
1095 // We have entered the condition variable's scope, so we're now able to
1096 // jump to the continue block.
1097 Continue = S.getInc() ? getJumpDestInCurrentScope("for.inc") : CondDest;
1098 BreakContinueStack.back().ContinueBlock = Continue;
1099 }
1100
1101 llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1102 // If there are any cleanups between here and the loop-exit scope,
1103 // create a block to stage a loop exit along.
1104 if (ForScope.requiresCleanups())
1105 ExitBlock = createBasicBlock("for.cond.cleanup");
1106
1107 // As long as the condition is true, iterate the loop.
1108 llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1109
1110 // C99 6.8.5p2/p4: The first substatement is executed if the expression
1111 // compares unequal to 0. The condition must be a scalar type.
1112 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1113 llvm::MDNode *Weights =
1114 createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1115 if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1116 BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1117 BoolCondVal, Stmt::getLikelihood(S.getBody()));
1118
1119 Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1120
1121 if (ExitBlock != LoopExit.getBlock()) {
1122 EmitBlock(ExitBlock);
1123 EmitBranchThroughCleanup(LoopExit);
1124 }
1125
1126 EmitBlock(ForBody);
1127 } else {
1128 // Treat it as a non-zero constant. Don't even create a new block for the
1129 // body, just fall into it.
1130 }
1131 incrementProfileCounter(&S);
1132
1133 {
1134 // Create a separate cleanup scope for the body, in case it is not
1135 // a compound statement.
1136 RunCleanupsScope BodyScope(*this);
1137 EmitStmt(S.getBody());
1138 }
1139
1140 // If there is an increment, emit it next.
1141 if (S.getInc()) {
1142 EmitBlock(Continue.getBlock());
1143 EmitStmt(S.getInc());
1144 }
1145
1146 BreakContinueStack.pop_back();
1147
1148 ConditionScope.ForceCleanup();
1149
1150 EmitStopPoint(&S);
1151 EmitBranch(CondBlock);
1152
1153 ForScope.ForceCleanup();
1154
1155 LoopStack.pop();
1156
1157 // Emit the fall-through block.
1158 EmitBlock(LoopExit.getBlock(), true);
1159 }
1160
1161 void
EmitCXXForRangeStmt(const CXXForRangeStmt & S,ArrayRef<const Attr * > ForAttrs)1162 CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
1163 ArrayRef<const Attr *> ForAttrs) {
1164 JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1165
1166 LexicalScope ForScope(*this, S.getSourceRange());
1167
1168 // Evaluate the first pieces before the loop.
1169 if (S.getInit())
1170 EmitStmt(S.getInit());
1171 EmitStmt(S.getRangeStmt());
1172 EmitStmt(S.getBeginStmt());
1173 EmitStmt(S.getEndStmt());
1174
1175 // Start the loop with a block that tests the condition.
1176 // If there's an increment, the continue scope will be overwritten
1177 // later.
1178 llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
1179 EmitBlock(CondBlock);
1180
1181 const SourceRange &R = S.getSourceRange();
1182 LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1183 SourceLocToDebugLoc(R.getBegin()),
1184 SourceLocToDebugLoc(R.getEnd()));
1185
1186 // If there are any cleanups between here and the loop-exit scope,
1187 // create a block to stage a loop exit along.
1188 llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1189 if (ForScope.requiresCleanups())
1190 ExitBlock = createBasicBlock("for.cond.cleanup");
1191
1192 // The loop body, consisting of the specified body and the loop variable.
1193 llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1194
1195 // The body is executed if the expression, contextually converted
1196 // to bool, is true.
1197 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1198 llvm::MDNode *Weights =
1199 createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1200 if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1201 BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1202 BoolCondVal, Stmt::getLikelihood(S.getBody()));
1203 Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1204
1205 if (ExitBlock != LoopExit.getBlock()) {
1206 EmitBlock(ExitBlock);
1207 EmitBranchThroughCleanup(LoopExit);
1208 }
1209
1210 EmitBlock(ForBody);
1211 incrementProfileCounter(&S);
1212
1213 // Create a block for the increment. In case of a 'continue', we jump there.
1214 JumpDest Continue = getJumpDestInCurrentScope("for.inc");
1215
1216 // Store the blocks to use for break and continue.
1217 BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1218
1219 {
1220 // Create a separate cleanup scope for the loop variable and body.
1221 LexicalScope BodyScope(*this, S.getSourceRange());
1222 EmitStmt(S.getLoopVarStmt());
1223 EmitStmt(S.getBody());
1224 }
1225
1226 EmitStopPoint(&S);
1227 // If there is an increment, emit it next.
1228 EmitBlock(Continue.getBlock());
1229 EmitStmt(S.getInc());
1230
1231 BreakContinueStack.pop_back();
1232
1233 EmitBranch(CondBlock);
1234
1235 ForScope.ForceCleanup();
1236
1237 LoopStack.pop();
1238
1239 // Emit the fall-through block.
1240 EmitBlock(LoopExit.getBlock(), true);
1241 }
1242
EmitReturnOfRValue(RValue RV,QualType Ty)1243 void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
1244 if (RV.isScalar()) {
1245 Builder.CreateStore(RV.getScalarVal(), ReturnValue);
1246 } else if (RV.isAggregate()) {
1247 LValue Dest = MakeAddrLValue(ReturnValue, Ty);
1248 LValue Src = MakeAddrLValue(RV.getAggregateAddress(), Ty);
1249 EmitAggregateCopy(Dest, Src, Ty, getOverlapForReturnValue());
1250 } else {
1251 EmitStoreOfComplex(RV.getComplexVal(), MakeAddrLValue(ReturnValue, Ty),
1252 /*init*/ true);
1253 }
1254 EmitBranchThroughCleanup(ReturnBlock);
1255 }
1256
1257 namespace {
1258 // RAII struct used to save and restore a return statment's result expression.
1259 struct SaveRetExprRAII {
SaveRetExprRAII__anon07ca51380111::SaveRetExprRAII1260 SaveRetExprRAII(const Expr *RetExpr, CodeGenFunction &CGF)
1261 : OldRetExpr(CGF.RetExpr), CGF(CGF) {
1262 CGF.RetExpr = RetExpr;
1263 }
~SaveRetExprRAII__anon07ca51380111::SaveRetExprRAII1264 ~SaveRetExprRAII() { CGF.RetExpr = OldRetExpr; }
1265 const Expr *OldRetExpr;
1266 CodeGenFunction &CGF;
1267 };
1268 } // namespace
1269
1270 /// If we have 'return f(...);', where both caller and callee are SwiftAsync,
1271 /// codegen it as 'tail call ...; ret void;'.
makeTailCallIfSwiftAsync(const CallExpr * CE,CGBuilderTy & Builder,const CGFunctionInfo * CurFnInfo)1272 static void makeTailCallIfSwiftAsync(const CallExpr *CE, CGBuilderTy &Builder,
1273 const CGFunctionInfo *CurFnInfo) {
1274 auto calleeQualType = CE->getCallee()->getType();
1275 const FunctionType *calleeType = nullptr;
1276 if (calleeQualType->isFunctionPointerType() ||
1277 calleeQualType->isFunctionReferenceType() ||
1278 calleeQualType->isBlockPointerType() ||
1279 calleeQualType->isMemberFunctionPointerType()) {
1280 calleeType = calleeQualType->getPointeeType()->castAs<FunctionType>();
1281 } else if (auto *ty = dyn_cast<FunctionType>(calleeQualType)) {
1282 calleeType = ty;
1283 } else if (auto CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
1284 if (auto methodDecl = CMCE->getMethodDecl()) {
1285 // getMethodDecl() doesn't handle member pointers at the moment.
1286 calleeType = methodDecl->getType()->castAs<FunctionType>();
1287 } else {
1288 return;
1289 }
1290 } else {
1291 return;
1292 }
1293 if (calleeType->getCallConv() == CallingConv::CC_SwiftAsync &&
1294 (CurFnInfo->getASTCallingConvention() == CallingConv::CC_SwiftAsync)) {
1295 auto CI = cast<llvm::CallInst>(&Builder.GetInsertBlock()->back());
1296 CI->setTailCallKind(llvm::CallInst::TCK_MustTail);
1297 Builder.CreateRetVoid();
1298 Builder.ClearInsertionPoint();
1299 }
1300 }
1301
1302 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
1303 /// if the function returns void, or may be missing one if the function returns
1304 /// non-void. Fun stuff :).
EmitReturnStmt(const ReturnStmt & S)1305 void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
1306 if (requiresReturnValueCheck()) {
1307 llvm::Constant *SLoc = EmitCheckSourceLocation(S.getBeginLoc());
1308 auto *SLocPtr =
1309 new llvm::GlobalVariable(CGM.getModule(), SLoc->getType(), false,
1310 llvm::GlobalVariable::PrivateLinkage, SLoc);
1311 SLocPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1312 CGM.getSanitizerMetadata()->disableSanitizerForGlobal(SLocPtr);
1313 assert(ReturnLocation.isValid() && "No valid return location");
1314 Builder.CreateStore(SLocPtr, ReturnLocation);
1315 }
1316
1317 // Returning from an outlined SEH helper is UB, and we already warn on it.
1318 if (IsOutlinedSEHHelper) {
1319 Builder.CreateUnreachable();
1320 Builder.ClearInsertionPoint();
1321 }
1322
1323 // Emit the result value, even if unused, to evaluate the side effects.
1324 const Expr *RV = S.getRetValue();
1325
1326 // Record the result expression of the return statement. The recorded
1327 // expression is used to determine whether a block capture's lifetime should
1328 // end at the end of the full expression as opposed to the end of the scope
1329 // enclosing the block expression.
1330 //
1331 // This permits a small, easily-implemented exception to our over-conservative
1332 // rules about not jumping to statements following block literals with
1333 // non-trivial cleanups.
1334 SaveRetExprRAII SaveRetExpr(RV, *this);
1335
1336 RunCleanupsScope cleanupScope(*this);
1337 if (const auto *EWC = dyn_cast_or_null<ExprWithCleanups>(RV))
1338 RV = EWC->getSubExpr();
1339 // FIXME: Clean this up by using an LValue for ReturnTemp,
1340 // EmitStoreThroughLValue, and EmitAnyExpr.
1341 // Check if the NRVO candidate was not globalized in OpenMP mode.
1342 if (getLangOpts().ElideConstructors && S.getNRVOCandidate() &&
1343 S.getNRVOCandidate()->isNRVOVariable() &&
1344 (!getLangOpts().OpenMP ||
1345 !CGM.getOpenMPRuntime()
1346 .getAddressOfLocalVariable(*this, S.getNRVOCandidate())
1347 .isValid())) {
1348 // Apply the named return value optimization for this return statement,
1349 // which means doing nothing: the appropriate result has already been
1350 // constructed into the NRVO variable.
1351
1352 // If there is an NRVO flag for this variable, set it to 1 into indicate
1353 // that the cleanup code should not destroy the variable.
1354 if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()])
1355 Builder.CreateFlagStore(Builder.getTrue(), NRVOFlag);
1356 } else if (!ReturnValue.isValid() || (RV && RV->getType()->isVoidType())) {
1357 // Make sure not to return anything, but evaluate the expression
1358 // for side effects.
1359 if (RV) {
1360 EmitAnyExpr(RV);
1361 if (auto *CE = dyn_cast<CallExpr>(RV))
1362 makeTailCallIfSwiftAsync(CE, Builder, CurFnInfo);
1363 }
1364 } else if (!RV) {
1365 // Do nothing (return value is left uninitialized)
1366 } else if (FnRetTy->isReferenceType()) {
1367 // If this function returns a reference, take the address of the expression
1368 // rather than the value.
1369 RValue Result = EmitReferenceBindingToExpr(RV);
1370 Builder.CreateStore(Result.getScalarVal(), ReturnValue);
1371 } else {
1372 switch (getEvaluationKind(RV->getType())) {
1373 case TEK_Scalar:
1374 Builder.CreateStore(EmitScalarExpr(RV), ReturnValue);
1375 break;
1376 case TEK_Complex:
1377 EmitComplexExprIntoLValue(RV, MakeAddrLValue(ReturnValue, RV->getType()),
1378 /*isInit*/ true);
1379 break;
1380 case TEK_Aggregate:
1381 EmitAggExpr(RV, AggValueSlot::forAddr(
1382 ReturnValue, Qualifiers(),
1383 AggValueSlot::IsDestructed,
1384 AggValueSlot::DoesNotNeedGCBarriers,
1385 AggValueSlot::IsNotAliased,
1386 getOverlapForReturnValue()));
1387 break;
1388 }
1389 }
1390
1391 ++NumReturnExprs;
1392 if (!RV || RV->isEvaluatable(getContext()))
1393 ++NumSimpleReturnExprs;
1394
1395 cleanupScope.ForceCleanup();
1396 EmitBranchThroughCleanup(ReturnBlock);
1397 }
1398
EmitDeclStmt(const DeclStmt & S)1399 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
1400 // As long as debug info is modeled with instructions, we have to ensure we
1401 // have a place to insert here and write the stop point here.
1402 if (HaveInsertPoint())
1403 EmitStopPoint(&S);
1404
1405 for (const auto *I : S.decls())
1406 EmitDecl(*I);
1407 }
1408
EmitBreakStmt(const BreakStmt & S)1409 void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
1410 assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
1411
1412 // If this code is reachable then emit a stop point (if generating
1413 // debug info). We have to do this ourselves because we are on the
1414 // "simple" statement path.
1415 if (HaveInsertPoint())
1416 EmitStopPoint(&S);
1417
1418 EmitBranchThroughCleanup(BreakContinueStack.back().BreakBlock);
1419 }
1420
EmitContinueStmt(const ContinueStmt & S)1421 void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
1422 assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
1423
1424 // If this code is reachable then emit a stop point (if generating
1425 // debug info). We have to do this ourselves because we are on the
1426 // "simple" statement path.
1427 if (HaveInsertPoint())
1428 EmitStopPoint(&S);
1429
1430 EmitBranchThroughCleanup(BreakContinueStack.back().ContinueBlock);
1431 }
1432
1433 /// EmitCaseStmtRange - If case statement range is not too big then
1434 /// add multiple cases to switch instruction, one for each value within
1435 /// the range. If range is too big then emit "if" condition check.
EmitCaseStmtRange(const CaseStmt & S,ArrayRef<const Attr * > Attrs)1436 void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S,
1437 ArrayRef<const Attr *> Attrs) {
1438 assert(S.getRHS() && "Expected RHS value in CaseStmt");
1439
1440 llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
1441 llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
1442
1443 // Emit the code for this case. We do this first to make sure it is
1444 // properly chained from our predecessor before generating the
1445 // switch machinery to enter this block.
1446 llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1447 EmitBlockWithFallThrough(CaseDest, &S);
1448 EmitStmt(S.getSubStmt());
1449
1450 // If range is empty, do nothing.
1451 if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS))
1452 return;
1453
1454 Stmt::Likelihood LH = Stmt::getLikelihood(Attrs);
1455 llvm::APInt Range = RHS - LHS;
1456 // FIXME: parameters such as this should not be hardcoded.
1457 if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) {
1458 // Range is small enough to add multiple switch instruction cases.
1459 uint64_t Total = getProfileCount(&S);
1460 unsigned NCases = Range.getZExtValue() + 1;
1461 // We only have one region counter for the entire set of cases here, so we
1462 // need to divide the weights evenly between the generated cases, ensuring
1463 // that the total weight is preserved. E.g., a weight of 5 over three cases
1464 // will be distributed as weights of 2, 2, and 1.
1465 uint64_t Weight = Total / NCases, Rem = Total % NCases;
1466 for (unsigned I = 0; I != NCases; ++I) {
1467 if (SwitchWeights)
1468 SwitchWeights->push_back(Weight + (Rem ? 1 : 0));
1469 else if (SwitchLikelihood)
1470 SwitchLikelihood->push_back(LH);
1471
1472 if (Rem)
1473 Rem--;
1474 SwitchInsn->addCase(Builder.getInt(LHS), CaseDest);
1475 ++LHS;
1476 }
1477 return;
1478 }
1479
1480 // The range is too big. Emit "if" condition into a new block,
1481 // making sure to save and restore the current insertion point.
1482 llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
1483
1484 // Push this test onto the chain of range checks (which terminates
1485 // in the default basic block). The switch's default will be changed
1486 // to the top of this chain after switch emission is complete.
1487 llvm::BasicBlock *FalseDest = CaseRangeBlock;
1488 CaseRangeBlock = createBasicBlock("sw.caserange");
1489
1490 CurFn->insert(CurFn->end(), CaseRangeBlock);
1491 Builder.SetInsertPoint(CaseRangeBlock);
1492
1493 // Emit range check.
1494 llvm::Value *Diff =
1495 Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
1496 llvm::Value *Cond =
1497 Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
1498
1499 llvm::MDNode *Weights = nullptr;
1500 if (SwitchWeights) {
1501 uint64_t ThisCount = getProfileCount(&S);
1502 uint64_t DefaultCount = (*SwitchWeights)[0];
1503 Weights = createProfileWeights(ThisCount, DefaultCount);
1504
1505 // Since we're chaining the switch default through each large case range, we
1506 // need to update the weight for the default, ie, the first case, to include
1507 // this case.
1508 (*SwitchWeights)[0] += ThisCount;
1509 } else if (SwitchLikelihood)
1510 Cond = emitCondLikelihoodViaExpectIntrinsic(Cond, LH);
1511
1512 Builder.CreateCondBr(Cond, CaseDest, FalseDest, Weights);
1513
1514 // Restore the appropriate insertion point.
1515 if (RestoreBB)
1516 Builder.SetInsertPoint(RestoreBB);
1517 else
1518 Builder.ClearInsertionPoint();
1519 }
1520
EmitCaseStmt(const CaseStmt & S,ArrayRef<const Attr * > Attrs)1521 void CodeGenFunction::EmitCaseStmt(const CaseStmt &S,
1522 ArrayRef<const Attr *> Attrs) {
1523 // If there is no enclosing switch instance that we're aware of, then this
1524 // case statement and its block can be elided. This situation only happens
1525 // when we've constant-folded the switch, are emitting the constant case,
1526 // and part of the constant case includes another case statement. For
1527 // instance: switch (4) { case 4: do { case 5: } while (1); }
1528 if (!SwitchInsn) {
1529 EmitStmt(S.getSubStmt());
1530 return;
1531 }
1532
1533 // Handle case ranges.
1534 if (S.getRHS()) {
1535 EmitCaseStmtRange(S, Attrs);
1536 return;
1537 }
1538
1539 llvm::ConstantInt *CaseVal =
1540 Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
1541
1542 // Emit debuginfo for the case value if it is an enum value.
1543 const ConstantExpr *CE;
1544 if (auto ICE = dyn_cast<ImplicitCastExpr>(S.getLHS()))
1545 CE = dyn_cast<ConstantExpr>(ICE->getSubExpr());
1546 else
1547 CE = dyn_cast<ConstantExpr>(S.getLHS());
1548 if (CE) {
1549 if (auto DE = dyn_cast<DeclRefExpr>(CE->getSubExpr()))
1550 if (CGDebugInfo *Dbg = getDebugInfo())
1551 if (CGM.getCodeGenOpts().hasReducedDebugInfo())
1552 Dbg->EmitGlobalVariable(DE->getDecl(),
1553 APValue(llvm::APSInt(CaseVal->getValue())));
1554 }
1555
1556 if (SwitchLikelihood)
1557 SwitchLikelihood->push_back(Stmt::getLikelihood(Attrs));
1558
1559 // If the body of the case is just a 'break', try to not emit an empty block.
1560 // If we're profiling or we're not optimizing, leave the block in for better
1561 // debug and coverage analysis.
1562 if (!CGM.getCodeGenOpts().hasProfileClangInstr() &&
1563 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1564 isa<BreakStmt>(S.getSubStmt())) {
1565 JumpDest Block = BreakContinueStack.back().BreakBlock;
1566
1567 // Only do this optimization if there are no cleanups that need emitting.
1568 if (isObviouslyBranchWithoutCleanups(Block)) {
1569 if (SwitchWeights)
1570 SwitchWeights->push_back(getProfileCount(&S));
1571 SwitchInsn->addCase(CaseVal, Block.getBlock());
1572
1573 // If there was a fallthrough into this case, make sure to redirect it to
1574 // the end of the switch as well.
1575 if (Builder.GetInsertBlock()) {
1576 Builder.CreateBr(Block.getBlock());
1577 Builder.ClearInsertionPoint();
1578 }
1579 return;
1580 }
1581 }
1582
1583 llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1584 EmitBlockWithFallThrough(CaseDest, &S);
1585 if (SwitchWeights)
1586 SwitchWeights->push_back(getProfileCount(&S));
1587 SwitchInsn->addCase(CaseVal, CaseDest);
1588
1589 // Recursively emitting the statement is acceptable, but is not wonderful for
1590 // code where we have many case statements nested together, i.e.:
1591 // case 1:
1592 // case 2:
1593 // case 3: etc.
1594 // Handling this recursively will create a new block for each case statement
1595 // that falls through to the next case which is IR intensive. It also causes
1596 // deep recursion which can run into stack depth limitations. Handle
1597 // sequential non-range case statements specially.
1598 //
1599 // TODO When the next case has a likelihood attribute the code returns to the
1600 // recursive algorithm. Maybe improve this case if it becomes common practice
1601 // to use a lot of attributes.
1602 const CaseStmt *CurCase = &S;
1603 const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt());
1604
1605 // Otherwise, iteratively add consecutive cases to this switch stmt.
1606 while (NextCase && NextCase->getRHS() == nullptr) {
1607 CurCase = NextCase;
1608 llvm::ConstantInt *CaseVal =
1609 Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
1610
1611 if (SwitchWeights)
1612 SwitchWeights->push_back(getProfileCount(NextCase));
1613 if (CGM.getCodeGenOpts().hasProfileClangInstr()) {
1614 CaseDest = createBasicBlock("sw.bb");
1615 EmitBlockWithFallThrough(CaseDest, CurCase);
1616 }
1617 // Since this loop is only executed when the CaseStmt has no attributes
1618 // use a hard-coded value.
1619 if (SwitchLikelihood)
1620 SwitchLikelihood->push_back(Stmt::LH_None);
1621
1622 SwitchInsn->addCase(CaseVal, CaseDest);
1623 NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
1624 }
1625
1626 // Generate a stop point for debug info if the case statement is
1627 // followed by a default statement. A fallthrough case before a
1628 // default case gets its own branch target.
1629 if (CurCase->getSubStmt()->getStmtClass() == Stmt::DefaultStmtClass)
1630 EmitStopPoint(CurCase);
1631
1632 // Normal default recursion for non-cases.
1633 EmitStmt(CurCase->getSubStmt());
1634 }
1635
EmitDefaultStmt(const DefaultStmt & S,ArrayRef<const Attr * > Attrs)1636 void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S,
1637 ArrayRef<const Attr *> Attrs) {
1638 // If there is no enclosing switch instance that we're aware of, then this
1639 // default statement can be elided. This situation only happens when we've
1640 // constant-folded the switch.
1641 if (!SwitchInsn) {
1642 EmitStmt(S.getSubStmt());
1643 return;
1644 }
1645
1646 llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest();
1647 assert(DefaultBlock->empty() &&
1648 "EmitDefaultStmt: Default block already defined?");
1649
1650 if (SwitchLikelihood)
1651 SwitchLikelihood->front() = Stmt::getLikelihood(Attrs);
1652
1653 EmitBlockWithFallThrough(DefaultBlock, &S);
1654
1655 EmitStmt(S.getSubStmt());
1656 }
1657
1658 /// CollectStatementsForCase - Given the body of a 'switch' statement and a
1659 /// constant value that is being switched on, see if we can dead code eliminate
1660 /// the body of the switch to a simple series of statements to emit. Basically,
1661 /// on a switch (5) we want to find these statements:
1662 /// case 5:
1663 /// printf(...); <--
1664 /// ++i; <--
1665 /// break;
1666 ///
1667 /// and add them to the ResultStmts vector. If it is unsafe to do this
1668 /// transformation (for example, one of the elided statements contains a label
1669 /// that might be jumped to), return CSFC_Failure. If we handled it and 'S'
1670 /// should include statements after it (e.g. the printf() line is a substmt of
1671 /// the case) then return CSFC_FallThrough. If we handled it and found a break
1672 /// statement, then return CSFC_Success.
1673 ///
1674 /// If Case is non-null, then we are looking for the specified case, checking
1675 /// that nothing we jump over contains labels. If Case is null, then we found
1676 /// the case and are looking for the break.
1677 ///
1678 /// If the recursive walk actually finds our Case, then we set FoundCase to
1679 /// true.
1680 ///
1681 enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success };
CollectStatementsForCase(const Stmt * S,const SwitchCase * Case,bool & FoundCase,SmallVectorImpl<const Stmt * > & ResultStmts)1682 static CSFC_Result CollectStatementsForCase(const Stmt *S,
1683 const SwitchCase *Case,
1684 bool &FoundCase,
1685 SmallVectorImpl<const Stmt*> &ResultStmts) {
1686 // If this is a null statement, just succeed.
1687 if (!S)
1688 return Case ? CSFC_Success : CSFC_FallThrough;
1689
1690 // If this is the switchcase (case 4: or default) that we're looking for, then
1691 // we're in business. Just add the substatement.
1692 if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) {
1693 if (S == Case) {
1694 FoundCase = true;
1695 return CollectStatementsForCase(SC->getSubStmt(), nullptr, FoundCase,
1696 ResultStmts);
1697 }
1698
1699 // Otherwise, this is some other case or default statement, just ignore it.
1700 return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase,
1701 ResultStmts);
1702 }
1703
1704 // If we are in the live part of the code and we found our break statement,
1705 // return a success!
1706 if (!Case && isa<BreakStmt>(S))
1707 return CSFC_Success;
1708
1709 // If this is a switch statement, then it might contain the SwitchCase, the
1710 // break, or neither.
1711 if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1712 // Handle this as two cases: we might be looking for the SwitchCase (if so
1713 // the skipped statements must be skippable) or we might already have it.
1714 CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end();
1715 bool StartedInLiveCode = FoundCase;
1716 unsigned StartSize = ResultStmts.size();
1717
1718 // If we've not found the case yet, scan through looking for it.
1719 if (Case) {
1720 // Keep track of whether we see a skipped declaration. The code could be
1721 // using the declaration even if it is skipped, so we can't optimize out
1722 // the decl if the kept statements might refer to it.
1723 bool HadSkippedDecl = false;
1724
1725 // If we're looking for the case, just see if we can skip each of the
1726 // substatements.
1727 for (; Case && I != E; ++I) {
1728 HadSkippedDecl |= CodeGenFunction::mightAddDeclToScope(*I);
1729
1730 switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) {
1731 case CSFC_Failure: return CSFC_Failure;
1732 case CSFC_Success:
1733 // A successful result means that either 1) that the statement doesn't
1734 // have the case and is skippable, or 2) does contain the case value
1735 // and also contains the break to exit the switch. In the later case,
1736 // we just verify the rest of the statements are elidable.
1737 if (FoundCase) {
1738 // If we found the case and skipped declarations, we can't do the
1739 // optimization.
1740 if (HadSkippedDecl)
1741 return CSFC_Failure;
1742
1743 for (++I; I != E; ++I)
1744 if (CodeGenFunction::ContainsLabel(*I, true))
1745 return CSFC_Failure;
1746 return CSFC_Success;
1747 }
1748 break;
1749 case CSFC_FallThrough:
1750 // If we have a fallthrough condition, then we must have found the
1751 // case started to include statements. Consider the rest of the
1752 // statements in the compound statement as candidates for inclusion.
1753 assert(FoundCase && "Didn't find case but returned fallthrough?");
1754 // We recursively found Case, so we're not looking for it anymore.
1755 Case = nullptr;
1756
1757 // If we found the case and skipped declarations, we can't do the
1758 // optimization.
1759 if (HadSkippedDecl)
1760 return CSFC_Failure;
1761 break;
1762 }
1763 }
1764
1765 if (!FoundCase)
1766 return CSFC_Success;
1767
1768 assert(!HadSkippedDecl && "fallthrough after skipping decl");
1769 }
1770
1771 // If we have statements in our range, then we know that the statements are
1772 // live and need to be added to the set of statements we're tracking.
1773 bool AnyDecls = false;
1774 for (; I != E; ++I) {
1775 AnyDecls |= CodeGenFunction::mightAddDeclToScope(*I);
1776
1777 switch (CollectStatementsForCase(*I, nullptr, FoundCase, ResultStmts)) {
1778 case CSFC_Failure: return CSFC_Failure;
1779 case CSFC_FallThrough:
1780 // A fallthrough result means that the statement was simple and just
1781 // included in ResultStmt, keep adding them afterwards.
1782 break;
1783 case CSFC_Success:
1784 // A successful result means that we found the break statement and
1785 // stopped statement inclusion. We just ensure that any leftover stmts
1786 // are skippable and return success ourselves.
1787 for (++I; I != E; ++I)
1788 if (CodeGenFunction::ContainsLabel(*I, true))
1789 return CSFC_Failure;
1790 return CSFC_Success;
1791 }
1792 }
1793
1794 // If we're about to fall out of a scope without hitting a 'break;', we
1795 // can't perform the optimization if there were any decls in that scope
1796 // (we'd lose their end-of-lifetime).
1797 if (AnyDecls) {
1798 // If the entire compound statement was live, there's one more thing we
1799 // can try before giving up: emit the whole thing as a single statement.
1800 // We can do that unless the statement contains a 'break;'.
1801 // FIXME: Such a break must be at the end of a construct within this one.
1802 // We could emit this by just ignoring the BreakStmts entirely.
1803 if (StartedInLiveCode && !CodeGenFunction::containsBreak(S)) {
1804 ResultStmts.resize(StartSize);
1805 ResultStmts.push_back(S);
1806 } else {
1807 return CSFC_Failure;
1808 }
1809 }
1810
1811 return CSFC_FallThrough;
1812 }
1813
1814 // Okay, this is some other statement that we don't handle explicitly, like a
1815 // for statement or increment etc. If we are skipping over this statement,
1816 // just verify it doesn't have labels, which would make it invalid to elide.
1817 if (Case) {
1818 if (CodeGenFunction::ContainsLabel(S, true))
1819 return CSFC_Failure;
1820 return CSFC_Success;
1821 }
1822
1823 // Otherwise, we want to include this statement. Everything is cool with that
1824 // so long as it doesn't contain a break out of the switch we're in.
1825 if (CodeGenFunction::containsBreak(S)) return CSFC_Failure;
1826
1827 // Otherwise, everything is great. Include the statement and tell the caller
1828 // that we fall through and include the next statement as well.
1829 ResultStmts.push_back(S);
1830 return CSFC_FallThrough;
1831 }
1832
1833 /// FindCaseStatementsForValue - Find the case statement being jumped to and
1834 /// then invoke CollectStatementsForCase to find the list of statements to emit
1835 /// for a switch on constant. See the comment above CollectStatementsForCase
1836 /// for more details.
FindCaseStatementsForValue(const SwitchStmt & S,const llvm::APSInt & ConstantCondValue,SmallVectorImpl<const Stmt * > & ResultStmts,ASTContext & C,const SwitchCase * & ResultCase)1837 static bool FindCaseStatementsForValue(const SwitchStmt &S,
1838 const llvm::APSInt &ConstantCondValue,
1839 SmallVectorImpl<const Stmt*> &ResultStmts,
1840 ASTContext &C,
1841 const SwitchCase *&ResultCase) {
1842 // First step, find the switch case that is being branched to. We can do this
1843 // efficiently by scanning the SwitchCase list.
1844 const SwitchCase *Case = S.getSwitchCaseList();
1845 const DefaultStmt *DefaultCase = nullptr;
1846
1847 for (; Case; Case = Case->getNextSwitchCase()) {
1848 // It's either a default or case. Just remember the default statement in
1849 // case we're not jumping to any numbered cases.
1850 if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) {
1851 DefaultCase = DS;
1852 continue;
1853 }
1854
1855 // Check to see if this case is the one we're looking for.
1856 const CaseStmt *CS = cast<CaseStmt>(Case);
1857 // Don't handle case ranges yet.
1858 if (CS->getRHS()) return false;
1859
1860 // If we found our case, remember it as 'case'.
1861 if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
1862 break;
1863 }
1864
1865 // If we didn't find a matching case, we use a default if it exists, or we
1866 // elide the whole switch body!
1867 if (!Case) {
1868 // It is safe to elide the body of the switch if it doesn't contain labels
1869 // etc. If it is safe, return successfully with an empty ResultStmts list.
1870 if (!DefaultCase)
1871 return !CodeGenFunction::ContainsLabel(&S);
1872 Case = DefaultCase;
1873 }
1874
1875 // Ok, we know which case is being jumped to, try to collect all the
1876 // statements that follow it. This can fail for a variety of reasons. Also,
1877 // check to see that the recursive walk actually found our case statement.
1878 // Insane cases like this can fail to find it in the recursive walk since we
1879 // don't handle every stmt kind:
1880 // switch (4) {
1881 // while (1) {
1882 // case 4: ...
1883 bool FoundCase = false;
1884 ResultCase = Case;
1885 return CollectStatementsForCase(S.getBody(), Case, FoundCase,
1886 ResultStmts) != CSFC_Failure &&
1887 FoundCase;
1888 }
1889
1890 static std::optional<SmallVector<uint64_t, 16>>
getLikelihoodWeights(ArrayRef<Stmt::Likelihood> Likelihoods)1891 getLikelihoodWeights(ArrayRef<Stmt::Likelihood> Likelihoods) {
1892 // Are there enough branches to weight them?
1893 if (Likelihoods.size() <= 1)
1894 return std::nullopt;
1895
1896 uint64_t NumUnlikely = 0;
1897 uint64_t NumNone = 0;
1898 uint64_t NumLikely = 0;
1899 for (const auto LH : Likelihoods) {
1900 switch (LH) {
1901 case Stmt::LH_Unlikely:
1902 ++NumUnlikely;
1903 break;
1904 case Stmt::LH_None:
1905 ++NumNone;
1906 break;
1907 case Stmt::LH_Likely:
1908 ++NumLikely;
1909 break;
1910 }
1911 }
1912
1913 // Is there a likelihood attribute used?
1914 if (NumUnlikely == 0 && NumLikely == 0)
1915 return std::nullopt;
1916
1917 // When multiple cases share the same code they can be combined during
1918 // optimization. In that case the weights of the branch will be the sum of
1919 // the individual weights. Make sure the combined sum of all neutral cases
1920 // doesn't exceed the value of a single likely attribute.
1921 // The additions both avoid divisions by 0 and make sure the weights of None
1922 // don't exceed the weight of Likely.
1923 const uint64_t Likely = INT32_MAX / (NumLikely + 2);
1924 const uint64_t None = Likely / (NumNone + 1);
1925 const uint64_t Unlikely = 0;
1926
1927 SmallVector<uint64_t, 16> Result;
1928 Result.reserve(Likelihoods.size());
1929 for (const auto LH : Likelihoods) {
1930 switch (LH) {
1931 case Stmt::LH_Unlikely:
1932 Result.push_back(Unlikely);
1933 break;
1934 case Stmt::LH_None:
1935 Result.push_back(None);
1936 break;
1937 case Stmt::LH_Likely:
1938 Result.push_back(Likely);
1939 break;
1940 }
1941 }
1942
1943 return Result;
1944 }
1945
EmitSwitchStmt(const SwitchStmt & S)1946 void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
1947 // Handle nested switch statements.
1948 llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
1949 SmallVector<uint64_t, 16> *SavedSwitchWeights = SwitchWeights;
1950 SmallVector<Stmt::Likelihood, 16> *SavedSwitchLikelihood = SwitchLikelihood;
1951 llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
1952
1953 // See if we can constant fold the condition of the switch and therefore only
1954 // emit the live case statement (if any) of the switch.
1955 llvm::APSInt ConstantCondValue;
1956 if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) {
1957 SmallVector<const Stmt*, 4> CaseStmts;
1958 const SwitchCase *Case = nullptr;
1959 if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts,
1960 getContext(), Case)) {
1961 if (Case)
1962 incrementProfileCounter(Case);
1963 RunCleanupsScope ExecutedScope(*this);
1964
1965 if (S.getInit())
1966 EmitStmt(S.getInit());
1967
1968 // Emit the condition variable if needed inside the entire cleanup scope
1969 // used by this special case for constant folded switches.
1970 if (S.getConditionVariable())
1971 EmitDecl(*S.getConditionVariable());
1972
1973 // At this point, we are no longer "within" a switch instance, so
1974 // we can temporarily enforce this to ensure that any embedded case
1975 // statements are not emitted.
1976 SwitchInsn = nullptr;
1977
1978 // Okay, we can dead code eliminate everything except this case. Emit the
1979 // specified series of statements and we're good.
1980 for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i)
1981 EmitStmt(CaseStmts[i]);
1982 incrementProfileCounter(&S);
1983
1984 // Now we want to restore the saved switch instance so that nested
1985 // switches continue to function properly
1986 SwitchInsn = SavedSwitchInsn;
1987
1988 return;
1989 }
1990 }
1991
1992 JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
1993
1994 RunCleanupsScope ConditionScope(*this);
1995
1996 if (S.getInit())
1997 EmitStmt(S.getInit());
1998
1999 if (S.getConditionVariable())
2000 EmitDecl(*S.getConditionVariable());
2001 llvm::Value *CondV = EmitScalarExpr(S.getCond());
2002
2003 // Create basic block to hold stuff that comes after switch
2004 // statement. We also need to create a default block now so that
2005 // explicit case ranges tests can have a place to jump to on
2006 // failure.
2007 llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default");
2008 SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock);
2009 if (PGO.haveRegionCounts()) {
2010 // Walk the SwitchCase list to find how many there are.
2011 uint64_t DefaultCount = 0;
2012 unsigned NumCases = 0;
2013 for (const SwitchCase *Case = S.getSwitchCaseList();
2014 Case;
2015 Case = Case->getNextSwitchCase()) {
2016 if (isa<DefaultStmt>(Case))
2017 DefaultCount = getProfileCount(Case);
2018 NumCases += 1;
2019 }
2020 SwitchWeights = new SmallVector<uint64_t, 16>();
2021 SwitchWeights->reserve(NumCases);
2022 // The default needs to be first. We store the edge count, so we already
2023 // know the right weight.
2024 SwitchWeights->push_back(DefaultCount);
2025 } else if (CGM.getCodeGenOpts().OptimizationLevel) {
2026 SwitchLikelihood = new SmallVector<Stmt::Likelihood, 16>();
2027 // Initialize the default case.
2028 SwitchLikelihood->push_back(Stmt::LH_None);
2029 }
2030
2031 CaseRangeBlock = DefaultBlock;
2032
2033 // Clear the insertion point to indicate we are in unreachable code.
2034 Builder.ClearInsertionPoint();
2035
2036 // All break statements jump to NextBlock. If BreakContinueStack is non-empty
2037 // then reuse last ContinueBlock.
2038 JumpDest OuterContinue;
2039 if (!BreakContinueStack.empty())
2040 OuterContinue = BreakContinueStack.back().ContinueBlock;
2041
2042 BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue));
2043
2044 // Emit switch body.
2045 EmitStmt(S.getBody());
2046
2047 BreakContinueStack.pop_back();
2048
2049 // Update the default block in case explicit case range tests have
2050 // been chained on top.
2051 SwitchInsn->setDefaultDest(CaseRangeBlock);
2052
2053 // If a default was never emitted:
2054 if (!DefaultBlock->getParent()) {
2055 // If we have cleanups, emit the default block so that there's a
2056 // place to jump through the cleanups from.
2057 if (ConditionScope.requiresCleanups()) {
2058 EmitBlock(DefaultBlock);
2059
2060 // Otherwise, just forward the default block to the switch end.
2061 } else {
2062 DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock());
2063 delete DefaultBlock;
2064 }
2065 }
2066
2067 ConditionScope.ForceCleanup();
2068
2069 // Emit continuation.
2070 EmitBlock(SwitchExit.getBlock(), true);
2071 incrementProfileCounter(&S);
2072
2073 // If the switch has a condition wrapped by __builtin_unpredictable,
2074 // create metadata that specifies that the switch is unpredictable.
2075 // Don't bother if not optimizing because that metadata would not be used.
2076 auto *Call = dyn_cast<CallExpr>(S.getCond());
2077 if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) {
2078 auto *FD = dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl());
2079 if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) {
2080 llvm::MDBuilder MDHelper(getLLVMContext());
2081 SwitchInsn->setMetadata(llvm::LLVMContext::MD_unpredictable,
2082 MDHelper.createUnpredictable());
2083 }
2084 }
2085
2086 if (SwitchWeights) {
2087 assert(SwitchWeights->size() == 1 + SwitchInsn->getNumCases() &&
2088 "switch weights do not match switch cases");
2089 // If there's only one jump destination there's no sense weighting it.
2090 if (SwitchWeights->size() > 1)
2091 SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
2092 createProfileWeights(*SwitchWeights));
2093 delete SwitchWeights;
2094 } else if (SwitchLikelihood) {
2095 assert(SwitchLikelihood->size() == 1 + SwitchInsn->getNumCases() &&
2096 "switch likelihoods do not match switch cases");
2097 std::optional<SmallVector<uint64_t, 16>> LHW =
2098 getLikelihoodWeights(*SwitchLikelihood);
2099 if (LHW) {
2100 llvm::MDBuilder MDHelper(CGM.getLLVMContext());
2101 SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
2102 createProfileWeights(*LHW));
2103 }
2104 delete SwitchLikelihood;
2105 }
2106 SwitchInsn = SavedSwitchInsn;
2107 SwitchWeights = SavedSwitchWeights;
2108 SwitchLikelihood = SavedSwitchLikelihood;
2109 CaseRangeBlock = SavedCRBlock;
2110 }
2111
2112 static std::string
SimplifyConstraint(const char * Constraint,const TargetInfo & Target,SmallVectorImpl<TargetInfo::ConstraintInfo> * OutCons=nullptr)2113 SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
2114 SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=nullptr) {
2115 std::string Result;
2116
2117 while (*Constraint) {
2118 switch (*Constraint) {
2119 default:
2120 Result += Target.convertConstraint(Constraint);
2121 break;
2122 // Ignore these
2123 case '*':
2124 case '?':
2125 case '!':
2126 case '=': // Will see this and the following in mult-alt constraints.
2127 case '+':
2128 break;
2129 case '#': // Ignore the rest of the constraint alternative.
2130 while (Constraint[1] && Constraint[1] != ',')
2131 Constraint++;
2132 break;
2133 case '&':
2134 case '%':
2135 Result += *Constraint;
2136 while (Constraint[1] && Constraint[1] == *Constraint)
2137 Constraint++;
2138 break;
2139 case ',':
2140 Result += "|";
2141 break;
2142 case 'g':
2143 Result += "imr";
2144 break;
2145 case '[': {
2146 assert(OutCons &&
2147 "Must pass output names to constraints with a symbolic name");
2148 unsigned Index;
2149 bool result = Target.resolveSymbolicName(Constraint, *OutCons, Index);
2150 assert(result && "Could not resolve symbolic name"); (void)result;
2151 Result += llvm::utostr(Index);
2152 break;
2153 }
2154 }
2155
2156 Constraint++;
2157 }
2158
2159 return Result;
2160 }
2161
2162 /// AddVariableConstraints - Look at AsmExpr and if it is a variable declared
2163 /// as using a particular register add that as a constraint that will be used
2164 /// in this asm stmt.
2165 static std::string
AddVariableConstraints(const std::string & Constraint,const Expr & AsmExpr,const TargetInfo & Target,CodeGenModule & CGM,const AsmStmt & Stmt,const bool EarlyClobber,std::string * GCCReg=nullptr)2166 AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr,
2167 const TargetInfo &Target, CodeGenModule &CGM,
2168 const AsmStmt &Stmt, const bool EarlyClobber,
2169 std::string *GCCReg = nullptr) {
2170 const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
2171 if (!AsmDeclRef)
2172 return Constraint;
2173 const ValueDecl &Value = *AsmDeclRef->getDecl();
2174 const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
2175 if (!Variable)
2176 return Constraint;
2177 if (Variable->getStorageClass() != SC_Register)
2178 return Constraint;
2179 AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
2180 if (!Attr)
2181 return Constraint;
2182 StringRef Register = Attr->getLabel();
2183 assert(Target.isValidGCCRegisterName(Register));
2184 // We're using validateOutputConstraint here because we only care if
2185 // this is a register constraint.
2186 TargetInfo::ConstraintInfo Info(Constraint, "");
2187 if (Target.validateOutputConstraint(Info) &&
2188 !Info.allowsRegister()) {
2189 CGM.ErrorUnsupported(&Stmt, "__asm__");
2190 return Constraint;
2191 }
2192 // Canonicalize the register here before returning it.
2193 Register = Target.getNormalizedGCCRegisterName(Register);
2194 if (GCCReg != nullptr)
2195 *GCCReg = Register.str();
2196 return (EarlyClobber ? "&{" : "{") + Register.str() + "}";
2197 }
2198
EmitAsmInputLValue(const TargetInfo::ConstraintInfo & Info,LValue InputValue,QualType InputType,std::string & ConstraintStr,SourceLocation Loc)2199 std::pair<llvm::Value*, llvm::Type *> CodeGenFunction::EmitAsmInputLValue(
2200 const TargetInfo::ConstraintInfo &Info, LValue InputValue,
2201 QualType InputType, std::string &ConstraintStr, SourceLocation Loc) {
2202 if (Info.allowsRegister() || !Info.allowsMemory()) {
2203 if (CodeGenFunction::hasScalarEvaluationKind(InputType))
2204 return {EmitLoadOfLValue(InputValue, Loc).getScalarVal(), nullptr};
2205
2206 llvm::Type *Ty = ConvertType(InputType);
2207 uint64_t Size = CGM.getDataLayout().getTypeSizeInBits(Ty);
2208 if ((Size <= 64 && llvm::isPowerOf2_64(Size)) ||
2209 getTargetHooks().isScalarizableAsmOperand(*this, Ty)) {
2210 Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2211
2212 return {
2213 Builder.CreateLoad(InputValue.getAddress(*this).withElementType(Ty)),
2214 nullptr};
2215 }
2216 }
2217
2218 Address Addr = InputValue.getAddress(*this);
2219 ConstraintStr += '*';
2220 return {Addr.getPointer(), Addr.getElementType()};
2221 }
2222
2223 std::pair<llvm::Value *, llvm::Type *>
EmitAsmInput(const TargetInfo::ConstraintInfo & Info,const Expr * InputExpr,std::string & ConstraintStr)2224 CodeGenFunction::EmitAsmInput(const TargetInfo::ConstraintInfo &Info,
2225 const Expr *InputExpr,
2226 std::string &ConstraintStr) {
2227 // If this can't be a register or memory, i.e., has to be a constant
2228 // (immediate or symbolic), try to emit it as such.
2229 if (!Info.allowsRegister() && !Info.allowsMemory()) {
2230 if (Info.requiresImmediateConstant()) {
2231 Expr::EvalResult EVResult;
2232 InputExpr->EvaluateAsRValue(EVResult, getContext(), true);
2233
2234 llvm::APSInt IntResult;
2235 if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
2236 getContext()))
2237 return {llvm::ConstantInt::get(getLLVMContext(), IntResult), nullptr};
2238 }
2239
2240 Expr::EvalResult Result;
2241 if (InputExpr->EvaluateAsInt(Result, getContext()))
2242 return {llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt()),
2243 nullptr};
2244 }
2245
2246 if (Info.allowsRegister() || !Info.allowsMemory())
2247 if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType()))
2248 return {EmitScalarExpr(InputExpr), nullptr};
2249 if (InputExpr->getStmtClass() == Expr::CXXThisExprClass)
2250 return {EmitScalarExpr(InputExpr), nullptr};
2251 InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
2252 LValue Dest = EmitLValue(InputExpr);
2253 return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr,
2254 InputExpr->getExprLoc());
2255 }
2256
2257 /// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline
2258 /// asm call instruction. The !srcloc MDNode contains a list of constant
2259 /// integers which are the source locations of the start of each line in the
2260 /// asm.
getAsmSrcLocInfo(const StringLiteral * Str,CodeGenFunction & CGF)2261 static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str,
2262 CodeGenFunction &CGF) {
2263 SmallVector<llvm::Metadata *, 8> Locs;
2264 // Add the location of the first line to the MDNode.
2265 Locs.push_back(llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
2266 CGF.Int64Ty, Str->getBeginLoc().getRawEncoding())));
2267 StringRef StrVal = Str->getString();
2268 if (!StrVal.empty()) {
2269 const SourceManager &SM = CGF.CGM.getContext().getSourceManager();
2270 const LangOptions &LangOpts = CGF.CGM.getLangOpts();
2271 unsigned StartToken = 0;
2272 unsigned ByteOffset = 0;
2273
2274 // Add the location of the start of each subsequent line of the asm to the
2275 // MDNode.
2276 for (unsigned i = 0, e = StrVal.size() - 1; i != e; ++i) {
2277 if (StrVal[i] != '\n') continue;
2278 SourceLocation LineLoc = Str->getLocationOfByte(
2279 i + 1, SM, LangOpts, CGF.getTarget(), &StartToken, &ByteOffset);
2280 Locs.push_back(llvm::ConstantAsMetadata::get(
2281 llvm::ConstantInt::get(CGF.Int64Ty, LineLoc.getRawEncoding())));
2282 }
2283 }
2284
2285 return llvm::MDNode::get(CGF.getLLVMContext(), Locs);
2286 }
2287
UpdateAsmCallInst(llvm::CallBase & Result,bool HasSideEffect,bool HasUnwindClobber,bool ReadOnly,bool ReadNone,bool NoMerge,const AsmStmt & S,const std::vector<llvm::Type * > & ResultRegTypes,const std::vector<llvm::Type * > & ArgElemTypes,CodeGenFunction & CGF,std::vector<llvm::Value * > & RegResults)2288 static void UpdateAsmCallInst(llvm::CallBase &Result, bool HasSideEffect,
2289 bool HasUnwindClobber, bool ReadOnly,
2290 bool ReadNone, bool NoMerge, const AsmStmt &S,
2291 const std::vector<llvm::Type *> &ResultRegTypes,
2292 const std::vector<llvm::Type *> &ArgElemTypes,
2293 CodeGenFunction &CGF,
2294 std::vector<llvm::Value *> &RegResults) {
2295 if (!HasUnwindClobber)
2296 Result.addFnAttr(llvm::Attribute::NoUnwind);
2297
2298 if (NoMerge)
2299 Result.addFnAttr(llvm::Attribute::NoMerge);
2300 // Attach readnone and readonly attributes.
2301 if (!HasSideEffect) {
2302 if (ReadNone)
2303 Result.setDoesNotAccessMemory();
2304 else if (ReadOnly)
2305 Result.setOnlyReadsMemory();
2306 }
2307
2308 // Add elementtype attribute for indirect constraints.
2309 for (auto Pair : llvm::enumerate(ArgElemTypes)) {
2310 if (Pair.value()) {
2311 auto Attr = llvm::Attribute::get(
2312 CGF.getLLVMContext(), llvm::Attribute::ElementType, Pair.value());
2313 Result.addParamAttr(Pair.index(), Attr);
2314 }
2315 }
2316
2317 // Slap the source location of the inline asm into a !srcloc metadata on the
2318 // call.
2319 if (const auto *gccAsmStmt = dyn_cast<GCCAsmStmt>(&S))
2320 Result.setMetadata("srcloc",
2321 getAsmSrcLocInfo(gccAsmStmt->getAsmString(), CGF));
2322 else {
2323 // At least put the line number on MS inline asm blobs.
2324 llvm::Constant *Loc =
2325 llvm::ConstantInt::get(CGF.Int64Ty, S.getAsmLoc().getRawEncoding());
2326 Result.setMetadata("srcloc",
2327 llvm::MDNode::get(CGF.getLLVMContext(),
2328 llvm::ConstantAsMetadata::get(Loc)));
2329 }
2330
2331 if (CGF.getLangOpts().assumeFunctionsAreConvergent())
2332 // Conservatively, mark all inline asm blocks in CUDA or OpenCL as
2333 // convergent (meaning, they may call an intrinsically convergent op, such
2334 // as bar.sync, and so can't have certain optimizations applied around
2335 // them).
2336 Result.addFnAttr(llvm::Attribute::Convergent);
2337 // Extract all of the register value results from the asm.
2338 if (ResultRegTypes.size() == 1) {
2339 RegResults.push_back(&Result);
2340 } else {
2341 for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) {
2342 llvm::Value *Tmp = CGF.Builder.CreateExtractValue(&Result, i, "asmresult");
2343 RegResults.push_back(Tmp);
2344 }
2345 }
2346 }
2347
2348 static void
EmitAsmStores(CodeGenFunction & CGF,const AsmStmt & S,const llvm::ArrayRef<llvm::Value * > RegResults,const llvm::ArrayRef<llvm::Type * > ResultRegTypes,const llvm::ArrayRef<llvm::Type * > ResultTruncRegTypes,const llvm::ArrayRef<LValue> ResultRegDests,const llvm::ArrayRef<QualType> ResultRegQualTys,const llvm::BitVector & ResultTypeRequiresCast,const llvm::BitVector & ResultRegIsFlagReg)2349 EmitAsmStores(CodeGenFunction &CGF, const AsmStmt &S,
2350 const llvm::ArrayRef<llvm::Value *> RegResults,
2351 const llvm::ArrayRef<llvm::Type *> ResultRegTypes,
2352 const llvm::ArrayRef<llvm::Type *> ResultTruncRegTypes,
2353 const llvm::ArrayRef<LValue> ResultRegDests,
2354 const llvm::ArrayRef<QualType> ResultRegQualTys,
2355 const llvm::BitVector &ResultTypeRequiresCast,
2356 const llvm::BitVector &ResultRegIsFlagReg) {
2357 CGBuilderTy &Builder = CGF.Builder;
2358 CodeGenModule &CGM = CGF.CGM;
2359 llvm::LLVMContext &CTX = CGF.getLLVMContext();
2360
2361 assert(RegResults.size() == ResultRegTypes.size());
2362 assert(RegResults.size() == ResultTruncRegTypes.size());
2363 assert(RegResults.size() == ResultRegDests.size());
2364 // ResultRegDests can be also populated by addReturnRegisterOutputs() above,
2365 // in which case its size may grow.
2366 assert(ResultTypeRequiresCast.size() <= ResultRegDests.size());
2367 assert(ResultRegIsFlagReg.size() <= ResultRegDests.size());
2368
2369 for (unsigned i = 0, e = RegResults.size(); i != e; ++i) {
2370 llvm::Value *Tmp = RegResults[i];
2371 llvm::Type *TruncTy = ResultTruncRegTypes[i];
2372
2373 if ((i < ResultRegIsFlagReg.size()) && ResultRegIsFlagReg[i]) {
2374 // Target must guarantee the Value `Tmp` here is lowered to a boolean
2375 // value.
2376 llvm::Constant *Two = llvm::ConstantInt::get(Tmp->getType(), 2);
2377 llvm::Value *IsBooleanValue =
2378 Builder.CreateCmp(llvm::CmpInst::ICMP_ULT, Tmp, Two);
2379 llvm::Function *FnAssume = CGM.getIntrinsic(llvm::Intrinsic::assume);
2380 Builder.CreateCall(FnAssume, IsBooleanValue);
2381 }
2382
2383 // If the result type of the LLVM IR asm doesn't match the result type of
2384 // the expression, do the conversion.
2385 if (ResultRegTypes[i] != TruncTy) {
2386
2387 // Truncate the integer result to the right size, note that TruncTy can be
2388 // a pointer.
2389 if (TruncTy->isFloatingPointTy())
2390 Tmp = Builder.CreateFPTrunc(Tmp, TruncTy);
2391 else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) {
2392 uint64_t ResSize = CGM.getDataLayout().getTypeSizeInBits(TruncTy);
2393 Tmp = Builder.CreateTrunc(
2394 Tmp, llvm::IntegerType::get(CTX, (unsigned)ResSize));
2395 Tmp = Builder.CreateIntToPtr(Tmp, TruncTy);
2396 } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) {
2397 uint64_t TmpSize =
2398 CGM.getDataLayout().getTypeSizeInBits(Tmp->getType());
2399 Tmp = Builder.CreatePtrToInt(
2400 Tmp, llvm::IntegerType::get(CTX, (unsigned)TmpSize));
2401 Tmp = Builder.CreateTrunc(Tmp, TruncTy);
2402 } else if (Tmp->getType()->isIntegerTy() && TruncTy->isIntegerTy()) {
2403 Tmp = Builder.CreateZExtOrTrunc(Tmp, TruncTy);
2404 } else if (Tmp->getType()->isVectorTy() || TruncTy->isVectorTy()) {
2405 Tmp = Builder.CreateBitCast(Tmp, TruncTy);
2406 }
2407 }
2408
2409 LValue Dest = ResultRegDests[i];
2410 // ResultTypeRequiresCast elements correspond to the first
2411 // ResultTypeRequiresCast.size() elements of RegResults.
2412 if ((i < ResultTypeRequiresCast.size()) && ResultTypeRequiresCast[i]) {
2413 unsigned Size = CGF.getContext().getTypeSize(ResultRegQualTys[i]);
2414 Address A = Dest.getAddress(CGF).withElementType(ResultRegTypes[i]);
2415 if (CGF.getTargetHooks().isScalarizableAsmOperand(CGF, TruncTy)) {
2416 Builder.CreateStore(Tmp, A);
2417 continue;
2418 }
2419
2420 QualType Ty =
2421 CGF.getContext().getIntTypeForBitwidth(Size, /*Signed=*/false);
2422 if (Ty.isNull()) {
2423 const Expr *OutExpr = S.getOutputExpr(i);
2424 CGM.getDiags().Report(OutExpr->getExprLoc(),
2425 diag::err_store_value_to_reg);
2426 return;
2427 }
2428 Dest = CGF.MakeAddrLValue(A, Ty);
2429 }
2430 CGF.EmitStoreThroughLValue(RValue::get(Tmp), Dest);
2431 }
2432 }
2433
EmitHipStdParUnsupportedAsm(CodeGenFunction * CGF,const AsmStmt & S)2434 static void EmitHipStdParUnsupportedAsm(CodeGenFunction *CGF,
2435 const AsmStmt &S) {
2436 constexpr auto Name = "__ASM__hipstdpar_unsupported";
2437
2438 StringRef Asm;
2439 if (auto GCCAsm = dyn_cast<GCCAsmStmt>(&S))
2440 Asm = GCCAsm->getAsmString()->getString();
2441
2442 auto &Ctx = CGF->CGM.getLLVMContext();
2443
2444 auto StrTy = llvm::ConstantDataArray::getString(Ctx, Asm);
2445 auto FnTy = llvm::FunctionType::get(llvm::Type::getVoidTy(Ctx),
2446 {StrTy->getType()}, false);
2447 auto UBF = CGF->CGM.getModule().getOrInsertFunction(Name, FnTy);
2448
2449 CGF->Builder.CreateCall(UBF, {StrTy});
2450 }
2451
EmitAsmStmt(const AsmStmt & S)2452 void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
2453 // Pop all cleanup blocks at the end of the asm statement.
2454 CodeGenFunction::RunCleanupsScope Cleanups(*this);
2455
2456 // Assemble the final asm string.
2457 std::string AsmString = S.generateAsmString(getContext());
2458
2459 // Get all the output and input constraints together.
2460 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
2461 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
2462
2463 bool IsHipStdPar = getLangOpts().HIPStdPar && getLangOpts().CUDAIsDevice;
2464 bool IsValidTargetAsm = true;
2465 for (unsigned i = 0, e = S.getNumOutputs(); i != e && IsValidTargetAsm; i++) {
2466 StringRef Name;
2467 if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2468 Name = GAS->getOutputName(i);
2469 TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), Name);
2470 bool IsValid = getTarget().validateOutputConstraint(Info); (void)IsValid;
2471 if (IsHipStdPar && !IsValid)
2472 IsValidTargetAsm = false;
2473 else
2474 assert(IsValid && "Failed to parse output constraint");
2475 OutputConstraintInfos.push_back(Info);
2476 }
2477
2478 for (unsigned i = 0, e = S.getNumInputs(); i != e && IsValidTargetAsm; i++) {
2479 StringRef Name;
2480 if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2481 Name = GAS->getInputName(i);
2482 TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), Name);
2483 bool IsValid =
2484 getTarget().validateInputConstraint(OutputConstraintInfos, Info);
2485 if (IsHipStdPar && !IsValid)
2486 IsValidTargetAsm = false;
2487 else
2488 assert(IsValid && "Failed to parse input constraint");
2489 InputConstraintInfos.push_back(Info);
2490 }
2491
2492 if (!IsValidTargetAsm)
2493 return EmitHipStdParUnsupportedAsm(this, S);
2494
2495 std::string Constraints;
2496
2497 std::vector<LValue> ResultRegDests;
2498 std::vector<QualType> ResultRegQualTys;
2499 std::vector<llvm::Type *> ResultRegTypes;
2500 std::vector<llvm::Type *> ResultTruncRegTypes;
2501 std::vector<llvm::Type *> ArgTypes;
2502 std::vector<llvm::Type *> ArgElemTypes;
2503 std::vector<llvm::Value*> Args;
2504 llvm::BitVector ResultTypeRequiresCast;
2505 llvm::BitVector ResultRegIsFlagReg;
2506
2507 // Keep track of inout constraints.
2508 std::string InOutConstraints;
2509 std::vector<llvm::Value*> InOutArgs;
2510 std::vector<llvm::Type*> InOutArgTypes;
2511 std::vector<llvm::Type*> InOutArgElemTypes;
2512
2513 // Keep track of out constraints for tied input operand.
2514 std::vector<std::string> OutputConstraints;
2515
2516 // Keep track of defined physregs.
2517 llvm::SmallSet<std::string, 8> PhysRegOutputs;
2518
2519 // An inline asm can be marked readonly if it meets the following conditions:
2520 // - it doesn't have any sideeffects
2521 // - it doesn't clobber memory
2522 // - it doesn't return a value by-reference
2523 // It can be marked readnone if it doesn't have any input memory constraints
2524 // in addition to meeting the conditions listed above.
2525 bool ReadOnly = true, ReadNone = true;
2526
2527 for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
2528 TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
2529
2530 // Simplify the output constraint.
2531 std::string OutputConstraint(S.getOutputConstraint(i));
2532 OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1,
2533 getTarget(), &OutputConstraintInfos);
2534
2535 const Expr *OutExpr = S.getOutputExpr(i);
2536 OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
2537
2538 std::string GCCReg;
2539 OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr,
2540 getTarget(), CGM, S,
2541 Info.earlyClobber(),
2542 &GCCReg);
2543 // Give an error on multiple outputs to same physreg.
2544 if (!GCCReg.empty() && !PhysRegOutputs.insert(GCCReg).second)
2545 CGM.Error(S.getAsmLoc(), "multiple outputs to hard register: " + GCCReg);
2546
2547 OutputConstraints.push_back(OutputConstraint);
2548 LValue Dest = EmitLValue(OutExpr);
2549 if (!Constraints.empty())
2550 Constraints += ',';
2551
2552 // If this is a register output, then make the inline asm return it
2553 // by-value. If this is a memory result, return the value by-reference.
2554 QualType QTy = OutExpr->getType();
2555 const bool IsScalarOrAggregate = hasScalarEvaluationKind(QTy) ||
2556 hasAggregateEvaluationKind(QTy);
2557 if (!Info.allowsMemory() && IsScalarOrAggregate) {
2558
2559 Constraints += "=" + OutputConstraint;
2560 ResultRegQualTys.push_back(QTy);
2561 ResultRegDests.push_back(Dest);
2562
2563 bool IsFlagReg = llvm::StringRef(OutputConstraint).starts_with("{@cc");
2564 ResultRegIsFlagReg.push_back(IsFlagReg);
2565
2566 llvm::Type *Ty = ConvertTypeForMem(QTy);
2567 const bool RequiresCast = Info.allowsRegister() &&
2568 (getTargetHooks().isScalarizableAsmOperand(*this, Ty) ||
2569 Ty->isAggregateType());
2570
2571 ResultTruncRegTypes.push_back(Ty);
2572 ResultTypeRequiresCast.push_back(RequiresCast);
2573
2574 if (RequiresCast) {
2575 unsigned Size = getContext().getTypeSize(QTy);
2576 Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2577 }
2578 ResultRegTypes.push_back(Ty);
2579 // If this output is tied to an input, and if the input is larger, then
2580 // we need to set the actual result type of the inline asm node to be the
2581 // same as the input type.
2582 if (Info.hasMatchingInput()) {
2583 unsigned InputNo;
2584 for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) {
2585 TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo];
2586 if (Input.hasTiedOperand() && Input.getTiedOperand() == i)
2587 break;
2588 }
2589 assert(InputNo != S.getNumInputs() && "Didn't find matching input!");
2590
2591 QualType InputTy = S.getInputExpr(InputNo)->getType();
2592 QualType OutputType = OutExpr->getType();
2593
2594 uint64_t InputSize = getContext().getTypeSize(InputTy);
2595 if (getContext().getTypeSize(OutputType) < InputSize) {
2596 // Form the asm to return the value as a larger integer or fp type.
2597 ResultRegTypes.back() = ConvertType(InputTy);
2598 }
2599 }
2600 if (llvm::Type* AdjTy =
2601 getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2602 ResultRegTypes.back()))
2603 ResultRegTypes.back() = AdjTy;
2604 else {
2605 CGM.getDiags().Report(S.getAsmLoc(),
2606 diag::err_asm_invalid_type_in_input)
2607 << OutExpr->getType() << OutputConstraint;
2608 }
2609
2610 // Update largest vector width for any vector types.
2611 if (auto *VT = dyn_cast<llvm::VectorType>(ResultRegTypes.back()))
2612 LargestVectorWidth =
2613 std::max((uint64_t)LargestVectorWidth,
2614 VT->getPrimitiveSizeInBits().getKnownMinValue());
2615 } else {
2616 Address DestAddr = Dest.getAddress(*this);
2617 // Matrix types in memory are represented by arrays, but accessed through
2618 // vector pointers, with the alignment specified on the access operation.
2619 // For inline assembly, update pointer arguments to use vector pointers.
2620 // Otherwise there will be a mis-match if the matrix is also an
2621 // input-argument which is represented as vector.
2622 if (isa<MatrixType>(OutExpr->getType().getCanonicalType()))
2623 DestAddr = DestAddr.withElementType(ConvertType(OutExpr->getType()));
2624
2625 ArgTypes.push_back(DestAddr.getType());
2626 ArgElemTypes.push_back(DestAddr.getElementType());
2627 Args.push_back(DestAddr.getPointer());
2628 Constraints += "=*";
2629 Constraints += OutputConstraint;
2630 ReadOnly = ReadNone = false;
2631 }
2632
2633 if (Info.isReadWrite()) {
2634 InOutConstraints += ',';
2635
2636 const Expr *InputExpr = S.getOutputExpr(i);
2637 llvm::Value *Arg;
2638 llvm::Type *ArgElemType;
2639 std::tie(Arg, ArgElemType) = EmitAsmInputLValue(
2640 Info, Dest, InputExpr->getType(), InOutConstraints,
2641 InputExpr->getExprLoc());
2642
2643 if (llvm::Type* AdjTy =
2644 getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2645 Arg->getType()))
2646 Arg = Builder.CreateBitCast(Arg, AdjTy);
2647
2648 // Update largest vector width for any vector types.
2649 if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2650 LargestVectorWidth =
2651 std::max((uint64_t)LargestVectorWidth,
2652 VT->getPrimitiveSizeInBits().getKnownMinValue());
2653 // Only tie earlyclobber physregs.
2654 if (Info.allowsRegister() && (GCCReg.empty() || Info.earlyClobber()))
2655 InOutConstraints += llvm::utostr(i);
2656 else
2657 InOutConstraints += OutputConstraint;
2658
2659 InOutArgTypes.push_back(Arg->getType());
2660 InOutArgElemTypes.push_back(ArgElemType);
2661 InOutArgs.push_back(Arg);
2662 }
2663 }
2664
2665 // If this is a Microsoft-style asm blob, store the return registers (EAX:EDX)
2666 // to the return value slot. Only do this when returning in registers.
2667 if (isa<MSAsmStmt>(&S)) {
2668 const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo();
2669 if (RetAI.isDirect() || RetAI.isExtend()) {
2670 // Make a fake lvalue for the return value slot.
2671 LValue ReturnSlot = MakeAddrLValueWithoutTBAA(ReturnValue, FnRetTy);
2672 CGM.getTargetCodeGenInfo().addReturnRegisterOutputs(
2673 *this, ReturnSlot, Constraints, ResultRegTypes, ResultTruncRegTypes,
2674 ResultRegDests, AsmString, S.getNumOutputs());
2675 SawAsmBlock = true;
2676 }
2677 }
2678
2679 for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
2680 const Expr *InputExpr = S.getInputExpr(i);
2681
2682 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
2683
2684 if (Info.allowsMemory())
2685 ReadNone = false;
2686
2687 if (!Constraints.empty())
2688 Constraints += ',';
2689
2690 // Simplify the input constraint.
2691 std::string InputConstraint(S.getInputConstraint(i));
2692 InputConstraint = SimplifyConstraint(InputConstraint.c_str(), getTarget(),
2693 &OutputConstraintInfos);
2694
2695 InputConstraint = AddVariableConstraints(
2696 InputConstraint, *InputExpr->IgnoreParenNoopCasts(getContext()),
2697 getTarget(), CGM, S, false /* No EarlyClobber */);
2698
2699 std::string ReplaceConstraint (InputConstraint);
2700 llvm::Value *Arg;
2701 llvm::Type *ArgElemType;
2702 std::tie(Arg, ArgElemType) = EmitAsmInput(Info, InputExpr, Constraints);
2703
2704 // If this input argument is tied to a larger output result, extend the
2705 // input to be the same size as the output. The LLVM backend wants to see
2706 // the input and output of a matching constraint be the same size. Note
2707 // that GCC does not define what the top bits are here. We use zext because
2708 // that is usually cheaper, but LLVM IR should really get an anyext someday.
2709 if (Info.hasTiedOperand()) {
2710 unsigned Output = Info.getTiedOperand();
2711 QualType OutputType = S.getOutputExpr(Output)->getType();
2712 QualType InputTy = InputExpr->getType();
2713
2714 if (getContext().getTypeSize(OutputType) >
2715 getContext().getTypeSize(InputTy)) {
2716 // Use ptrtoint as appropriate so that we can do our extension.
2717 if (isa<llvm::PointerType>(Arg->getType()))
2718 Arg = Builder.CreatePtrToInt(Arg, IntPtrTy);
2719 llvm::Type *OutputTy = ConvertType(OutputType);
2720 if (isa<llvm::IntegerType>(OutputTy))
2721 Arg = Builder.CreateZExt(Arg, OutputTy);
2722 else if (isa<llvm::PointerType>(OutputTy))
2723 Arg = Builder.CreateZExt(Arg, IntPtrTy);
2724 else if (OutputTy->isFloatingPointTy())
2725 Arg = Builder.CreateFPExt(Arg, OutputTy);
2726 }
2727 // Deal with the tied operands' constraint code in adjustInlineAsmType.
2728 ReplaceConstraint = OutputConstraints[Output];
2729 }
2730 if (llvm::Type* AdjTy =
2731 getTargetHooks().adjustInlineAsmType(*this, ReplaceConstraint,
2732 Arg->getType()))
2733 Arg = Builder.CreateBitCast(Arg, AdjTy);
2734 else
2735 CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input)
2736 << InputExpr->getType() << InputConstraint;
2737
2738 // Update largest vector width for any vector types.
2739 if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2740 LargestVectorWidth =
2741 std::max((uint64_t)LargestVectorWidth,
2742 VT->getPrimitiveSizeInBits().getKnownMinValue());
2743
2744 ArgTypes.push_back(Arg->getType());
2745 ArgElemTypes.push_back(ArgElemType);
2746 Args.push_back(Arg);
2747 Constraints += InputConstraint;
2748 }
2749
2750 // Append the "input" part of inout constraints.
2751 for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
2752 ArgTypes.push_back(InOutArgTypes[i]);
2753 ArgElemTypes.push_back(InOutArgElemTypes[i]);
2754 Args.push_back(InOutArgs[i]);
2755 }
2756 Constraints += InOutConstraints;
2757
2758 // Labels
2759 SmallVector<llvm::BasicBlock *, 16> Transfer;
2760 llvm::BasicBlock *Fallthrough = nullptr;
2761 bool IsGCCAsmGoto = false;
2762 if (const auto *GS = dyn_cast<GCCAsmStmt>(&S)) {
2763 IsGCCAsmGoto = GS->isAsmGoto();
2764 if (IsGCCAsmGoto) {
2765 for (const auto *E : GS->labels()) {
2766 JumpDest Dest = getJumpDestForLabel(E->getLabel());
2767 Transfer.push_back(Dest.getBlock());
2768 if (!Constraints.empty())
2769 Constraints += ',';
2770 Constraints += "!i";
2771 }
2772 Fallthrough = createBasicBlock("asm.fallthrough");
2773 }
2774 }
2775
2776 bool HasUnwindClobber = false;
2777
2778 // Clobbers
2779 for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) {
2780 StringRef Clobber = S.getClobber(i);
2781
2782 if (Clobber == "memory")
2783 ReadOnly = ReadNone = false;
2784 else if (Clobber == "unwind") {
2785 HasUnwindClobber = true;
2786 continue;
2787 } else if (Clobber != "cc") {
2788 Clobber = getTarget().getNormalizedGCCRegisterName(Clobber);
2789 if (CGM.getCodeGenOpts().StackClashProtector &&
2790 getTarget().isSPRegName(Clobber)) {
2791 CGM.getDiags().Report(S.getAsmLoc(),
2792 diag::warn_stack_clash_protection_inline_asm);
2793 }
2794 }
2795
2796 if (isa<MSAsmStmt>(&S)) {
2797 if (Clobber == "eax" || Clobber == "edx") {
2798 if (Constraints.find("=&A") != std::string::npos)
2799 continue;
2800 std::string::size_type position1 =
2801 Constraints.find("={" + Clobber.str() + "}");
2802 if (position1 != std::string::npos) {
2803 Constraints.insert(position1 + 1, "&");
2804 continue;
2805 }
2806 std::string::size_type position2 = Constraints.find("=A");
2807 if (position2 != std::string::npos) {
2808 Constraints.insert(position2 + 1, "&");
2809 continue;
2810 }
2811 }
2812 }
2813 if (!Constraints.empty())
2814 Constraints += ',';
2815
2816 Constraints += "~{";
2817 Constraints += Clobber;
2818 Constraints += '}';
2819 }
2820
2821 assert(!(HasUnwindClobber && IsGCCAsmGoto) &&
2822 "unwind clobber can't be used with asm goto");
2823
2824 // Add machine specific clobbers
2825 std::string_view MachineClobbers = getTarget().getClobbers();
2826 if (!MachineClobbers.empty()) {
2827 if (!Constraints.empty())
2828 Constraints += ',';
2829 Constraints += MachineClobbers;
2830 }
2831
2832 llvm::Type *ResultType;
2833 if (ResultRegTypes.empty())
2834 ResultType = VoidTy;
2835 else if (ResultRegTypes.size() == 1)
2836 ResultType = ResultRegTypes[0];
2837 else
2838 ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes);
2839
2840 llvm::FunctionType *FTy =
2841 llvm::FunctionType::get(ResultType, ArgTypes, false);
2842
2843 bool HasSideEffect = S.isVolatile() || S.getNumOutputs() == 0;
2844
2845 llvm::InlineAsm::AsmDialect GnuAsmDialect =
2846 CGM.getCodeGenOpts().getInlineAsmDialect() == CodeGenOptions::IAD_ATT
2847 ? llvm::InlineAsm::AD_ATT
2848 : llvm::InlineAsm::AD_Intel;
2849 llvm::InlineAsm::AsmDialect AsmDialect = isa<MSAsmStmt>(&S) ?
2850 llvm::InlineAsm::AD_Intel : GnuAsmDialect;
2851
2852 llvm::InlineAsm *IA = llvm::InlineAsm::get(
2853 FTy, AsmString, Constraints, HasSideEffect,
2854 /* IsAlignStack */ false, AsmDialect, HasUnwindClobber);
2855 std::vector<llvm::Value*> RegResults;
2856 llvm::CallBrInst *CBR;
2857 llvm::DenseMap<llvm::BasicBlock *, SmallVector<llvm::Value *, 4>>
2858 CBRRegResults;
2859 if (IsGCCAsmGoto) {
2860 CBR = Builder.CreateCallBr(IA, Fallthrough, Transfer, Args);
2861 EmitBlock(Fallthrough);
2862 UpdateAsmCallInst(*CBR, HasSideEffect, false, ReadOnly, ReadNone,
2863 InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
2864 *this, RegResults);
2865 // Because we are emitting code top to bottom, we don't have enough
2866 // information at this point to know precisely whether we have a critical
2867 // edge. If we have outputs, split all indirect destinations.
2868 if (!RegResults.empty()) {
2869 unsigned i = 0;
2870 for (llvm::BasicBlock *Dest : CBR->getIndirectDests()) {
2871 llvm::Twine SynthName = Dest->getName() + ".split";
2872 llvm::BasicBlock *SynthBB = createBasicBlock(SynthName);
2873 llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
2874 Builder.SetInsertPoint(SynthBB);
2875
2876 if (ResultRegTypes.size() == 1) {
2877 CBRRegResults[SynthBB].push_back(CBR);
2878 } else {
2879 for (unsigned j = 0, e = ResultRegTypes.size(); j != e; ++j) {
2880 llvm::Value *Tmp = Builder.CreateExtractValue(CBR, j, "asmresult");
2881 CBRRegResults[SynthBB].push_back(Tmp);
2882 }
2883 }
2884
2885 EmitBranch(Dest);
2886 EmitBlock(SynthBB);
2887 CBR->setIndirectDest(i++, SynthBB);
2888 }
2889 }
2890 } else if (HasUnwindClobber) {
2891 llvm::CallBase *Result = EmitCallOrInvoke(IA, Args, "");
2892 UpdateAsmCallInst(*Result, HasSideEffect, true, ReadOnly, ReadNone,
2893 InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
2894 *this, RegResults);
2895 } else {
2896 llvm::CallInst *Result =
2897 Builder.CreateCall(IA, Args, getBundlesForFunclet(IA));
2898 UpdateAsmCallInst(*Result, HasSideEffect, false, ReadOnly, ReadNone,
2899 InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
2900 *this, RegResults);
2901 }
2902
2903 EmitAsmStores(*this, S, RegResults, ResultRegTypes, ResultTruncRegTypes,
2904 ResultRegDests, ResultRegQualTys, ResultTypeRequiresCast,
2905 ResultRegIsFlagReg);
2906
2907 // If this is an asm goto with outputs, repeat EmitAsmStores, but with a
2908 // different insertion point; one for each indirect destination and with
2909 // CBRRegResults rather than RegResults.
2910 if (IsGCCAsmGoto && !CBRRegResults.empty()) {
2911 for (llvm::BasicBlock *Succ : CBR->getIndirectDests()) {
2912 llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
2913 Builder.SetInsertPoint(Succ, --(Succ->end()));
2914 EmitAsmStores(*this, S, CBRRegResults[Succ], ResultRegTypes,
2915 ResultTruncRegTypes, ResultRegDests, ResultRegQualTys,
2916 ResultTypeRequiresCast, ResultRegIsFlagReg);
2917 }
2918 }
2919 }
2920
InitCapturedStruct(const CapturedStmt & S)2921 LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) {
2922 const RecordDecl *RD = S.getCapturedRecordDecl();
2923 QualType RecordTy = getContext().getRecordType(RD);
2924
2925 // Initialize the captured struct.
2926 LValue SlotLV =
2927 MakeAddrLValue(CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
2928
2929 RecordDecl::field_iterator CurField = RD->field_begin();
2930 for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(),
2931 E = S.capture_init_end();
2932 I != E; ++I, ++CurField) {
2933 LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
2934 if (CurField->hasCapturedVLAType()) {
2935 EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
2936 } else {
2937 EmitInitializerForField(*CurField, LV, *I);
2938 }
2939 }
2940
2941 return SlotLV;
2942 }
2943
2944 /// Generate an outlined function for the body of a CapturedStmt, store any
2945 /// captured variables into the captured struct, and call the outlined function.
2946 llvm::Function *
EmitCapturedStmt(const CapturedStmt & S,CapturedRegionKind K)2947 CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) {
2948 LValue CapStruct = InitCapturedStruct(S);
2949
2950 // Emit the CapturedDecl
2951 CodeGenFunction CGF(CGM, true);
2952 CGCapturedStmtRAII CapInfoRAII(CGF, new CGCapturedStmtInfo(S, K));
2953 llvm::Function *F = CGF.GenerateCapturedStmtFunction(S);
2954 delete CGF.CapturedStmtInfo;
2955
2956 // Emit call to the helper function.
2957 EmitCallOrInvoke(F, CapStruct.getPointer(*this));
2958
2959 return F;
2960 }
2961
GenerateCapturedStmtArgument(const CapturedStmt & S)2962 Address CodeGenFunction::GenerateCapturedStmtArgument(const CapturedStmt &S) {
2963 LValue CapStruct = InitCapturedStruct(S);
2964 return CapStruct.getAddress(*this);
2965 }
2966
2967 /// Creates the outlined function for a CapturedStmt.
2968 llvm::Function *
GenerateCapturedStmtFunction(const CapturedStmt & S)2969 CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
2970 assert(CapturedStmtInfo &&
2971 "CapturedStmtInfo should be set when generating the captured function");
2972 const CapturedDecl *CD = S.getCapturedDecl();
2973 const RecordDecl *RD = S.getCapturedRecordDecl();
2974 SourceLocation Loc = S.getBeginLoc();
2975 assert(CD->hasBody() && "missing CapturedDecl body");
2976
2977 // Build the argument list.
2978 ASTContext &Ctx = CGM.getContext();
2979 FunctionArgList Args;
2980 Args.append(CD->param_begin(), CD->param_end());
2981
2982 // Create the function declaration.
2983 const CGFunctionInfo &FuncInfo =
2984 CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args);
2985 llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
2986
2987 llvm::Function *F =
2988 llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage,
2989 CapturedStmtInfo->getHelperName(), &CGM.getModule());
2990 CGM.SetInternalFunctionAttributes(CD, F, FuncInfo);
2991 if (CD->isNothrow())
2992 F->addFnAttr(llvm::Attribute::NoUnwind);
2993
2994 // Generate the function.
2995 StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args, CD->getLocation(),
2996 CD->getBody()->getBeginLoc());
2997 // Set the context parameter in CapturedStmtInfo.
2998 Address DeclPtr = GetAddrOfLocalVar(CD->getContextParam());
2999 CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr));
3000
3001 // Initialize variable-length arrays.
3002 LValue Base = MakeNaturalAlignAddrLValue(CapturedStmtInfo->getContextValue(),
3003 Ctx.getTagDeclType(RD));
3004 for (auto *FD : RD->fields()) {
3005 if (FD->hasCapturedVLAType()) {
3006 auto *ExprArg =
3007 EmitLoadOfLValue(EmitLValueForField(Base, FD), S.getBeginLoc())
3008 .getScalarVal();
3009 auto VAT = FD->getCapturedVLAType();
3010 VLASizeMap[VAT->getSizeExpr()] = ExprArg;
3011 }
3012 }
3013
3014 // If 'this' is captured, load it into CXXThisValue.
3015 if (CapturedStmtInfo->isCXXThisExprCaptured()) {
3016 FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl();
3017 LValue ThisLValue = EmitLValueForField(Base, FD);
3018 CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal();
3019 }
3020
3021 PGO.assignRegionCounters(GlobalDecl(CD), F);
3022 CapturedStmtInfo->EmitBody(*this, CD->getBody());
3023 FinishFunction(CD->getBodyRBrace());
3024
3025 return F;
3026 }
3027