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