xref: /llvm-project/llvm/lib/CodeGen/MachineDebugify.cpp (revision 1adeeabb79afbe966a45050f07e0bd6f446f8aa6)
1 //===- MachineDebugify.cpp - Attach synthetic debug info to everything ----===//
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 pass attaches synthetic debug info to everything. It can be used
10 /// to create targeted tests for debug info preservation.
11 ///
12 /// This isn't intended to have feature parity with Debugify.
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/CodeGen/MachineFunctionPass.h"
16 #include "llvm/CodeGen/MachineModuleInfo.h"
17 #include "llvm/CodeGen/Passes.h"
18 #include "llvm/IR/DIBuilder.h"
19 #include "llvm/IR/DebugInfo.h"
20 #include "llvm/InitializePasses.h"
21 #include "llvm/Transforms/Utils/Debugify.h"
22 
23 #define DEBUG_TYPE "mir-debugify"
24 
25 using namespace llvm;
26 
27 namespace {
28 bool applyDebugifyMetadataToMachineFunction(MachineModuleInfo &MMI,
29                                             DIBuilder &DIB, Function &F) {
30   MachineFunction &MF = MMI.getOrCreateMachineFunction(F);
31 
32   DISubprogram *SP = F.getSubprogram();
33   assert(SP && "IR Debugify just created it?");
34 
35   LLVMContext &Ctx = F.getParent()->getContext();
36   unsigned NextLine = SP->getLine();
37 
38   for (MachineBasicBlock &MBB : MF) {
39     for (MachineInstr &MI : MBB) {
40       // This will likely emit line numbers beyond the end of the imagined
41       // source function and into subsequent ones. We don't do anything about
42       // that as it doesn't really matter to the compiler where the line is in
43       // the imaginary source code.
44       MI.setDebugLoc(DILocation::get(Ctx, NextLine++, 1, SP));
45     }
46   }
47 
48   return true;
49 }
50 
51 /// ModulePass for attaching synthetic debug info to everything, used with the
52 /// legacy module pass manager.
53 struct DebugifyMachineModule : public ModulePass {
54   bool runOnModule(Module &M) override {
55     MachineModuleInfo &MMI =
56         getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
57     return applyDebugifyMetadata(
58         M, M.functions(),
59         "ModuleDebugify: ", [&](DIBuilder &DIB, Function &F) -> bool {
60           return applyDebugifyMetadataToMachineFunction(MMI, DIB, F);
61         });
62   }
63 
64   DebugifyMachineModule() : ModulePass(ID) {}
65 
66   void getAnalysisUsage(AnalysisUsage &AU) const override {
67     AU.addRequired<MachineModuleInfoWrapperPass>();
68     AU.addPreserved<MachineModuleInfoWrapperPass>();
69   }
70 
71   static char ID; // Pass identification.
72 };
73 char DebugifyMachineModule::ID = 0;
74 
75 } // end anonymous namespace
76 
77 INITIALIZE_PASS_BEGIN(DebugifyMachineModule, DEBUG_TYPE,
78                       "Machine Debugify Module", false, false)
79 INITIALIZE_PASS_END(DebugifyMachineModule, DEBUG_TYPE,
80                     "Machine Debugify Module", false, false)
81 
82 ModulePass *createDebugifyMachineModulePass() {
83   return new DebugifyMachineModule();
84 }
85