1; RUN: llc < %s | FileCheck %s --check-prefix=ASM 2; RUN: llc -filetype=obj < %s | llvm-readobj --codeview | FileCheck %s --check-prefix=OBJ 3 4; PR38857 5 6; When stack realignment is required by dynamic allocas are not used, the 7; compiler will address locals with the ESP register. However, if call argument 8; set up uses PUSH instructions, ESP may vary over the course of the function. 9; This means it's not useful as a base register for describing the locations of 10; variables. Instead, our CodeView output prefers to use the VFRAME virtual 11; register, which is defined in the FPO data as $T0. Make sure we define it. 12 13; Original C++ test case, which uses __thiscall to encourage PUSH conversion: 14; struct Foo { 15; int x = 42; 16; int __declspec(noinline) foo(); 17; void __declspec(noinline) bar(int *a, int *b, double *c); 18; }; 19; int Foo::foo() { 20; int a = 1; 21; int b = 2; 22; double __declspec(align(8)) force_alignment = 0.42; 23; bar(&a, &b, &force_alignment); 24; x += (int)force_alignment; 25; return x; 26; } 27; void Foo::bar(int *a, int *b, double *c) { 28; __debugbreak(); 29; *c += *a + *b; 30; } 31; int main() { 32; Foo o; 33; o.foo(); 34; } 35; This stops the debugger in bar, and locals in Foo::foo would be corrupt. 36 37; More reduced C code to generate this IR: 38; int getval(void); 39; void usevals(int *, int *, double *); 40; int realign_with_csrs(int x) { 41; int a = getval(); 42; double __declspec(align(8)) force_alignment = 0.42; 43; usevals(&a, &x, &force_alignment); 44; return x; 45; } 46 47; Match the prologue for the .cv_fpo* directives. 48; ASM-LABEL: _realign_with_csrs: 49; ASM: .cv_fpo_proc _realign_with_csrs 4 50; ASM: # %bb.0: # %entry 51; ASM: pushl %ebp 52; ASM: .cv_fpo_pushreg %ebp 53; ASM: movl %esp, %ebp 54; ASM: .cv_fpo_setframe %ebp 55; ASM: andl $-8, %esp 56; ASM: .cv_fpo_stackalign 8 57; ASM: subl $16, %esp 58; ASM: .cv_fpo_stackalloc 16 59; ASM: .cv_fpo_endprologue 60 61; 'x' should be EBP-relative, 'a' and 'force_alignment' ESP relative. 62; ASM: calll _getval 63; ASM-DAG: leal 8(%esp), %[[LEA_DBL:[^ ]*]] 64; ASM-DAG: leal 8(%ebp), %[[LEA_X:[^ ]*]] 65; ASM-DAG: leal 4(%esp), %[[LEA_A:[^ ]*]] 66; ASM: pushl %[[LEA_DBL]] 67; ASM: pushl %[[LEA_X]] 68; ASM: pushl %[[LEA_A]] 69; ASM: calll _usevals 70; ASM: addl $12, %esp 71 72; OBJ: Subsection [ 73; OBJ: SubSectionType: Symbols (0xF1) 74; OBJ: ] 75; OBJ: Subsection [ 76; OBJ: SubSectionType: FrameData (0xF5) 77; Really, the only important FrameFunc is the last one. 78; OBJ: FrameData { 79; OBJ: } 80; OBJ: FrameData { 81; OBJ: } 82; OBJ: FrameData { 83; OBJ: } 84; OBJ: FrameData { 85; OBJ: FrameFunc [ 86; OBJ-NEXT: $T1 $ebp 4 + = 87; OBJ-NEXT: $T0 $T1 4 - 8 @ = 88; OBJ-NEXT: $eip $T1 ^ = 89; OBJ-NEXT: $esp $T1 4 + = 90; OBJ-NEXT: $ebp $T1 4 - ^ = 91; OBJ-NEXT: ] 92; OBJ: } 93; OBJ: ] 94; OBJ: Subsection [ 95; OBJ: SubSectionType: Symbols (0xF1) 96; OBJ: GlobalProcIdSym { 97; OBJ: Kind: S_GPROC32_ID (0x1147) 98; OBJ: DisplayName: realign_with_csrs 99; OBJ: LinkageName: _realign_with_csrs 100; OBJ: } 101; The frame register for locals should be VFRAME, and EBP for parameters. 102; OBJ: FrameProcSym { 103; OBJ: Kind: S_FRAMEPROC (0x1012) 104; OBJ: TotalFrameBytes: 0x14 105; OBJ: LocalFramePtrReg: VFRAME (0x7536) 106; OBJ: ParamFramePtrReg: EBP (0x16) 107; OBJ: } 108; As seen in ASM, offset of x is 8. 109; OBJ: LocalSym { 110; OBJ: Kind: S_LOCAL (0x113E) 111; OBJ: Type: int (0x74) 112; OBJ: Flags [ (0x1) 113; OBJ: IsParameter (0x1) 114; OBJ: ] 115; OBJ: VarName: x 116; OBJ: } 117; OBJ: DefRangeFramePointerRelSym { 118; OBJ: Kind: S_DEFRANGE_FRAMEPOINTER_REL (0x1142) 119; OBJ: Offset: 8 120; OBJ: } 121; ESP is VFRAME - 16, ESP offset of 'a' is 4, so -12. 122; OBJ: LocalSym { 123; OBJ: Kind: S_LOCAL (0x113E) 124; OBJ: Type: int (0x74) 125; OBJ: Flags [ (0x0) 126; OBJ: ] 127; OBJ: VarName: a 128; OBJ: } 129; OBJ: DefRangeFramePointerRelSym { 130; OBJ: Kind: S_DEFRANGE_FRAMEPOINTER_REL (0x1142) 131; OBJ: Offset: -12 132; OBJ: } 133; ESP is VFRAME - 16, ESP offset of 'force_alignment' is 8, so -8. 134; OBJ: LocalSym { 135; OBJ: Kind: S_LOCAL (0x113E) 136; OBJ: Type: double (0x41) 137; OBJ: Flags [ (0x0) 138; OBJ: ] 139; OBJ: VarName: force_alignment 140; OBJ: } 141; OBJ: DefRangeFramePointerRelSym { 142; OBJ: Kind: S_DEFRANGE_FRAMEPOINTER_REL (0x1142) 143; OBJ: Offset: -8 144; OBJ: } 145; OBJ: ProcEnd { 146; OBJ: Kind: S_PROC_ID_END (0x114F) 147; OBJ: } 148; OBJ: ] 149 150; ModuleID = 't.c' 151source_filename = "t.c" 152target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32" 153target triple = "i386-pc-windows-msvc19.14.26433" 154 155; Function Attrs: nounwind 156define dso_local i32 @realign_with_csrs(i32 %x) local_unnamed_addr #0 !dbg !8 { 157entry: 158 %x.addr = alloca i32, align 4 159 %a = alloca i32, align 4 160 %force_alignment = alloca double, align 8 161 store i32 %x, i32* %x.addr, align 4, !tbaa !17 162 call void @llvm.dbg.declare(metadata i32* %x.addr, metadata !13, metadata !DIExpression()), !dbg !21 163 %0 = bitcast i32* %a to i8*, !dbg !22 164 call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %0) #4, !dbg !22 165 call void @llvm.dbg.declare(metadata i32* %a, metadata !14, metadata !DIExpression()), !dbg !22 166 %call = tail call i32 @getval() #4, !dbg !22 167 store i32 %call, i32* %a, align 4, !dbg !22, !tbaa !17 168 %1 = bitcast double* %force_alignment to i8*, !dbg !23 169 call void @llvm.lifetime.start.p0i8(i64 8, i8* nonnull %1) #4, !dbg !23 170 call void @llvm.dbg.declare(metadata double* %force_alignment, metadata !15, metadata !DIExpression()), !dbg !23 171 store double 4.200000e-01, double* %force_alignment, align 8, !dbg !23, !tbaa !24 172 call void @usevals(i32* nonnull %a, i32* nonnull %x.addr, double* nonnull %force_alignment) #4, !dbg !26 173 %2 = load i32, i32* %x.addr, align 4, !dbg !27, !tbaa !17 174 call void @llvm.lifetime.end.p0i8(i64 8, i8* nonnull %1) #4, !dbg !28 175 call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %0) #4, !dbg !28 176 ret i32 %2, !dbg !27 177} 178 179; Function Attrs: nounwind readnone speculatable 180declare void @llvm.dbg.declare(metadata, metadata, metadata) #1 181 182; Function Attrs: argmemonly nounwind 183declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #2 184 185declare dso_local i32 @getval() local_unnamed_addr #3 186 187declare dso_local void @usevals(i32*, i32*, double*) local_unnamed_addr #3 188 189; Function Attrs: argmemonly nounwind 190declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #2 191 192attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="pentium4" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" } 193attributes #1 = { nounwind readnone speculatable } 194attributes #2 = { argmemonly nounwind } 195attributes #3 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="pentium4" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" } 196attributes #4 = { nounwind } 197 198!llvm.dbg.cu = !{!0} 199!llvm.module.flags = !{!3, !4, !5, !6} 200!llvm.ident = !{!7} 201 202!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 8.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None) 203!1 = !DIFile(filename: "t.c", directory: "C:\5Csrc\5Cllvm-project\5Cbuild", checksumkind: CSK_MD5, checksum: "a646950309d5d01d8087fc10fea33941") 204!2 = !{} 205!3 = !{i32 1, !"NumRegisterParameters", i32 0} 206!4 = !{i32 2, !"CodeView", i32 1} 207!5 = !{i32 2, !"Debug Info Version", i32 3} 208!6 = !{i32 1, !"wchar_size", i32 2} 209!7 = !{!"clang version 8.0.0 "} 210!8 = distinct !DISubprogram(name: "realign_with_csrs", scope: !1, file: !1, line: 3, type: !9, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !12) 211!9 = !DISubroutineType(types: !10) 212!10 = !{!11, !11} 213!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) 214!12 = !{!13, !14, !15} 215!13 = !DILocalVariable(name: "x", arg: 1, scope: !8, file: !1, line: 3, type: !11) 216!14 = !DILocalVariable(name: "a", scope: !8, file: !1, line: 4, type: !11) 217!15 = !DILocalVariable(name: "force_alignment", scope: !8, file: !1, line: 5, type: !16, align: 64) 218!16 = !DIBasicType(name: "double", size: 64, encoding: DW_ATE_float) 219!17 = !{!18, !18, i64 0} 220!18 = !{!"int", !19, i64 0} 221!19 = !{!"omnipotent char", !20, i64 0} 222!20 = !{!"Simple C/C++ TBAA"} 223!21 = !DILocation(line: 3, scope: !8) 224!22 = !DILocation(line: 4, scope: !8) 225!23 = !DILocation(line: 5, scope: !8) 226!24 = !{!25, !25, i64 0} 227!25 = !{!"double", !19, i64 0} 228!26 = !DILocation(line: 6, scope: !8) 229!27 = !DILocation(line: 7, scope: !8) 230!28 = !DILocation(line: 8, scope: !8) 231