1 //===- MachineCheckDebugify.cpp - Check debug info ------------------------===//
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 /// \file This checks debug info after mir-debugify (+ pass-to-test). Currently
10 /// it simply checks the integrity of line info in DILocation and
11 /// DILocalVariable which mir-debugifiy generated before.
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/ADT/StringExtras.h"
15 #include "llvm/CodeGen/MachineBasicBlock.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/CodeGen/MachineModuleInfo.h"
18 #include "llvm/CodeGen/Passes.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/DebugInfoMetadata.h"
21 #include "llvm/InitializePasses.h"
22 #include "llvm/Pass.h"
23 
24 #define DEBUG_TYPE "mir-check-debugify"
25 
26 using namespace llvm;
27 
28 namespace {
29 
30 struct CheckDebugMachineModule : public ModulePass {
31   bool runOnModule(Module &M) override {
32     NamedMDNode *NMD = M.getNamedMetadata("llvm.mir.debugify");
33     if (!NMD) {
34       errs() << "WARNING: Please run mir-debugify to generate "
35                 "llvm.mir.debugify metadata first.\n";
36       return false;
37     }
38 
39     MachineModuleInfo &MMI =
40         getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
41 
42     auto getDebugifyOperand = [&](unsigned Idx) -> unsigned {
43       return mdconst::extract<ConstantInt>(NMD->getOperand(Idx)->getOperand(0))
44           ->getZExtValue();
45     };
46     assert(NMD->getNumOperands() == 2 &&
47            "llvm.mir.debugify should have exactly 2 operands!");
48     unsigned NumLines = getDebugifyOperand(0);
49     unsigned NumVars = getDebugifyOperand(1);
50     BitVector MissingLines{NumLines, true};
51     BitVector MissingVars{NumVars, true};
52 
53     for (Function &F : M.functions()) {
54       MachineFunction *MF = MMI.getMachineFunction(F);
55       if (!MF)
56         continue;
57       for (MachineBasicBlock &MBB : *MF) {
58         // Find missing lines.
59         // TODO: Avoid meta instructions other than dbg_val.
60         for (MachineInstr &MI : MBB) {
61           if (MI.isDebugValue())
62             continue;
63           const DebugLoc DL = MI.getDebugLoc();
64           if (DL && DL.getLine() != 0) {
65             MissingLines.reset(DL.getLine() - 1);
66             continue;
67           }
68 
69           if (!DL) {
70             errs() << "WARNING: Instruction with empty DebugLoc in function ";
71             errs() << F.getName() << " --";
72             MI.print(errs());
73           }
74         }
75 
76         // Find missing variables.
77         // TODO: Handle DBG_INSTR_REF which is under an experimental option now.
78         for (MachineInstr &MI : MBB) {
79           if (!MI.isDebugValue())
80             continue;
81           const DILocalVariable *LocalVar = MI.getDebugVariable();
82           unsigned Var = ~0U;
83 
84           (void)to_integer(LocalVar->getName(), Var, 10);
85           assert(Var <= NumVars && "Unexpected name for DILocalVariable");
86           MissingVars.reset(Var - 1);
87         }
88       }
89     }
90 
91     bool Fail = false;
92     for (unsigned Idx : MissingLines.set_bits()) {
93       errs() << "WARNING: Missing line " << Idx + 1 << "\n";
94       Fail = true;
95     }
96 
97     for (unsigned Idx : MissingVars.set_bits()) {
98       errs() << "WARNING: Missing variable " << Idx + 1 << "\n";
99       Fail = true;
100     }
101     errs() << "Machine IR debug info check: ";
102     errs() << (Fail ? "FAIL" : "PASS") << "\n";
103 
104     return false;
105   }
106 
107   CheckDebugMachineModule() : ModulePass(ID) {}
108 
109   void getAnalysisUsage(AnalysisUsage &AU) const override {
110     AU.addRequired<MachineModuleInfoWrapperPass>();
111     AU.setPreservesAll();
112   }
113 
114   static char ID; // Pass identification.
115 };
116 char CheckDebugMachineModule::ID = 0;
117 
118 } // end anonymous namespace
119 
120 INITIALIZE_PASS_BEGIN(CheckDebugMachineModule, DEBUG_TYPE,
121                       "Machine Check Debug Module", false, false)
122 INITIALIZE_PASS_END(CheckDebugMachineModule, DEBUG_TYPE,
123                     "Machine Check Debug Module", false, false)
124 
125 ModulePass *llvm::createCheckDebugMachineModulePass() {
126   return new CheckDebugMachineModule();
127 }
128