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