[llvm] r322789 - [MachineOutliner] Add DISubprograms to outlined functions.
David Blaikie via llvm-commits
llvm-commits at lists.llvm.org
Wed Jan 17 18:20:25 PST 2018
Yeah +1 for not making a new CU if we can help it.
Also wondering about the name of this function - giving it the same name as
the original seems like it'd create issues for debuggers?
What exactly is outlining - it's taking a chunk of a function and pulling
it out into another function? I guess we already pick an interesting
mangled name for it to be unique and should probably use that? (maybe only
put the linkage name and not give it a non-linkage name? Since it doesn't
have a name in the source... but not sure if LLVM really supports a
nameless function (or if DWARF/debuggers are cool with that either?))
On Wed, Jan 17, 2018 at 6:06 PM Robinson, Paul <paul.robinson at sony.com>
wrote:
> Hi Jessica,
> Creating a whole new compilation unit for the outlined functions seems
> pretty extreme. For non-LTO compilations there should be only one; is
> there something keeping you from adding the functions to that CU? Or
> is that undesirable for some reason?
> Thanks,
> --paulr
>
> > -----Original Message-----
> > From: llvm-commits [mailto:llvm-commits-bounces at lists.llvm.org] On
> Behalf
> > Of Jessica Paquette via llvm-commits
> > Sent: Wednesday, January 17, 2018 4:01 PM
> > To: llvm-commits at lists.llvm.org
> > Subject: [llvm] r322789 - [MachineOutliner] Add DISubprograms to outlined
> > functions.
> >
> > Author: paquette
> > Date: Wed Jan 17 16:00:58 2018
> > New Revision: 322789
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=322789&view=rev
> > Log:
> > [MachineOutliner] Add DISubprograms to outlined functions.
> >
> > Before, it wasn't possible to get backtraces inside outlined functions.
> > This
> > commit adds DISubprograms to the IR functions created by the outliner
> > which
> > makes this possible. Also attached a test that ensures that the produced
> > debug information is correct. This is useful to users that want to debug
> > outlined code.
> >
> >
> > Added:
> > llvm/trunk/test/CodeGen/X86/machine-outliner-disubprogram.ll
> > Modified:
> > llvm/trunk/lib/CodeGen/MachineOutliner.cpp
> >
> > Modified: llvm/trunk/lib/CodeGen/MachineOutliner.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/llvm/trunk/lib/CodeGen/MachineOutliner.cpp?rev=322789&r1=322788&r2
> > =322789&view=diff
> >
> ==========================================================================
> > ====
> > --- llvm/trunk/lib/CodeGen/MachineOutliner.cpp (original)
> > +++ llvm/trunk/lib/CodeGen/MachineOutliner.cpp Wed Jan 17 16:00:58 2018
> > @@ -66,6 +66,7 @@
> > #include "llvm/CodeGen/TargetInstrInfo.h"
> > #include "llvm/CodeGen/TargetRegisterInfo.h"
> > #include "llvm/CodeGen/TargetSubtargetInfo.h"
> > +#include "llvm/IR/DIBuilder.h"
> > #include "llvm/IR/IRBuilder.h"
> > #include "llvm/Support/Allocator.h"
> > #include "llvm/Support/Debug.h"
> > @@ -776,6 +777,9 @@ struct MachineOutliner : public ModulePa
> > /// linkonceodr linkage.
> > bool OutlineFromLinkOnceODRs = false;
> >
> > + // Collection of IR functions created by the outliner.
> > + std::vector<Function *> CreatedIRFunctions;
> > +
> > StringRef getPassName() const override { return "Machine Outliner"; }
> >
> > void getAnalysisUsage(AnalysisUsage &AU) const override {
> > @@ -1210,6 +1214,9 @@ MachineOutliner::createOutlinedFunction(
> > F->setLinkage(GlobalValue::PrivateLinkage);
> > F->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
> >
> > + // Save F so that we can add debug info later if we need to.
> > + CreatedIRFunctions.push_back(F);
> > +
> > BasicBlock *EntryBB = BasicBlock::Create(C, "entry", F);
> > IRBuilder<> Builder(EntryBB);
> > Builder.CreateRetVoid();
> > @@ -1233,12 +1240,12 @@ MachineOutliner::createOutlinedFunction(
> > NewMI->dropMemRefs();
> >
> > // Don't keep debug information for outlined instructions.
> > - // FIXME: This means outlined functions are currently undebuggable.
> > NewMI->setDebugLoc(DebugLoc());
> > MBB.insert(MBB.end(), NewMI);
> > }
> >
> > TII.insertOutlinerEpilogue(MBB, MF, OF.MInfo);
> > +
> > return &MF;
> > }
> >
> > @@ -1379,5 +1386,43 @@ bool MachineOutliner::runOnModule(Module
> > pruneOverlaps(CandidateList, FunctionList, Mapper, MaxCandidateLen,
> > *TII);
> >
> > // Outline each of the candidates and return true if something was
> > outlined.
> > - return outline(M, CandidateList, FunctionList, Mapper);
> > + bool OutlinedSomething = outline(M, CandidateList, FunctionList,
> > Mapper);
> > +
> > + // If we have a compile unit, and we've outlined something, then set
> > debug
> > + // information on the outlined function.
> > + if (M.debug_compile_units_begin() != M.debug_compile_units_end() &&
> > + OutlinedSomething) {
> > + std::unique_ptr<DIBuilder> DB = llvm::make_unique<DIBuilder>(M);
> > +
> > + // Create a compile unit for the outlined function.
> > + DICompileUnit *MCU = *M.debug_compile_units_begin();
> > + DIFile *Unit = DB->createFile(M.getName(), "/");
> > + DB->createCompileUnit(MCU->getSourceLanguage(), Unit, "machine-
> > outliner",
> > + true, "", MCU->getRuntimeVersion(),
> > StringRef(),
> > + DICompileUnit::DebugEmissionKind::NoDebug);
> > +
> > + // Walk over each IR function we created in the outliner and create
> > + // DISubprograms for each function.
> > + for (Function *F : CreatedIRFunctions) {
> > + DISubprogram *SP = DB->createFunction(
> > + Unit /* Context */, F->getName(),
> > + StringRef() /* Empty linkage name. */, Unit /* File */,
> > + 0 /* Line numbers don't matter*/,
> > + DB->createSubroutineType(DB->getOrCreateTypeArray(None)), /*
> > void */
> > + false, true, 0, /* Line in scope doesn't matter*/
> > + DINode::DIFlags::FlagArtificial /* Compiler-generated code.
> */,
> > + true /* Outlined code is optimized code by definition. */);
> > +
> > + // Don't add any new variables to the subprogram.
> > + DB->finalizeSubprogram(SP);
> > +
> > + // Attach subprogram to the function.
> > + F->setSubprogram(SP);
> > + }
> > +
> > + // We're done with the DIBuilder.
> > + DB->finalize();
> > + }
> > +
> > + return OutlinedSomething;
> > }
> >
> > Added: llvm/trunk/test/CodeGen/X86/machine-outliner-disubprogram.ll
> > URL: http://llvm.org/viewvc/llvm-
> > project/llvm/trunk/test/CodeGen/X86/machine-outliner-
> > disubprogram.ll?rev=322789&view=auto
> >
> ==========================================================================
> > ====
> > --- llvm/trunk/test/CodeGen/X86/machine-outliner-disubprogram.ll (added)
> > +++ llvm/trunk/test/CodeGen/X86/machine-outliner-disubprogram.ll Wed Jan
> > 17 16:00:58 2018
> > @@ -0,0 +1,219 @@
> > +; Ensure that we can correctly emit a compile unit for outlined
> functions
> > and
> > +; that we correctly emit DISubprograms for those functions.
> > +; Also make sure that the DISubprograms reference the generated unit.
> > +; make sure that if there are two outlined functions in the program,
> > +; RUN: llc %s -enable-machine-outliner -mtriple=x86_64-apple-darwin -o
> > d.out -print-after=machine-outliner
> > +define void @f6() #0 !dbg !8 {
> > +entry:
> > + %dog = alloca i32, align 4
> > + %cat = alloca i32, align 4
> > + %pangolin = alloca i32, align 4
> > + call void @llvm.dbg.declare(metadata i32* %dog, metadata !11, metadata
> > !DIExpression()), !dbg !13
> > + store i32 16, i32* %dog, align 4, !dbg !13
> > + call void @llvm.dbg.declare(metadata i32* %cat, metadata !14, metadata
> > !DIExpression()), !dbg !15
> > + store i32 32, i32* %cat, align 4, !dbg !15
> > + call void @llvm.dbg.declare(metadata i32* %pangolin, metadata !16,
> > metadata !DIExpression()), !dbg !17
> > + store i32 48, i32* %pangolin, align 4, !dbg !17
> > + ret void, !dbg !18
> > +}
> > +
> > +declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
> > +
> > +define void @f5() #0 !dbg !19 {
> > +entry:
> > + %dog = alloca i32, align 4
> > + %cat = alloca i32, align 4
> > + %pangolin = alloca i32, align 4
> > + call void @llvm.dbg.declare(metadata i32* %dog, metadata !20, metadata
> > !DIExpression()), !dbg !21
> > + store i32 16, i32* %dog, align 4, !dbg !21
> > + call void @llvm.dbg.declare(metadata i32* %cat, metadata !22, metadata
> > !DIExpression()), !dbg !23
> > + store i32 32, i32* %cat, align 4, !dbg !23
> > + call void @llvm.dbg.declare(metadata i32* %pangolin, metadata !24,
> > metadata !DIExpression()), !dbg !25
> > + store i32 48, i32* %pangolin, align 4, !dbg !25
> > + ret void, !dbg !26
> > +}
> > +
> > +define void @f4() #0 !dbg !27 {
> > +entry:
> > + %dog = alloca i32, align 4
> > + %cat = alloca i32, align 4
> > + %pangolin = alloca i32, align 4
> > + call void @llvm.dbg.declare(metadata i32* %dog, metadata !28, metadata
> > !DIExpression()), !dbg !29
> > + store i32 16, i32* %dog, align 4, !dbg !29
> > + call void @llvm.dbg.declare(metadata i32* %cat, metadata !30, metadata
> > !DIExpression()), !dbg !31
> > + store i32 32, i32* %cat, align 4, !dbg !31
> > + call void @llvm.dbg.declare(metadata i32* %pangolin, metadata !32,
> > metadata !DIExpression()), !dbg !33
> > + store i32 48, i32* %pangolin, align 4, !dbg !33
> > + ret void, !dbg !34
> > +}
> > +
> > +define i32 @f1() #0 !dbg !35 {
> > +entry:
> > + %dog = alloca i32, align 4
> > + %cat = alloca i32, align 4
> > + %pangolin = alloca i32, align 4
> > + call void @llvm.dbg.declare(metadata i32* %dog, metadata !38, metadata
> > !DIExpression()), !dbg !39
> > + store i32 1, i32* %dog, align 4, !dbg !39
> > + call void @llvm.dbg.declare(metadata i32* %cat, metadata !40, metadata
> > !DIExpression()), !dbg !41
> > + store i32 2, i32* %cat, align 4, !dbg !41
> > + call void @llvm.dbg.declare(metadata i32* %pangolin, metadata !42,
> > metadata !DIExpression()), !dbg !43
> > + store i32 3, i32* %pangolin, align 4, !dbg !43
> > + store i32 16, i32* %dog, align 4, !dbg !44
> > + %0 = load i32, i32* %dog, align 4, !dbg !45
> > + ret i32 %0, !dbg !46
> > +}
> > +
> > +define i32 @f2() #0 !dbg !47 {
> > +entry:
> > + %dog = alloca i32, align 4
> > + %cat = alloca i32, align 4
> > + %pangolin = alloca i32, align 4
> > + call void @llvm.dbg.declare(metadata i32* %dog, metadata !48, metadata
> > !DIExpression()), !dbg !49
> > + store i32 1, i32* %dog, align 4, !dbg !49
> > + call void @llvm.dbg.declare(metadata i32* %cat, metadata !50, metadata
> > !DIExpression()), !dbg !51
> > + store i32 2, i32* %cat, align 4, !dbg !51
> > + call void @llvm.dbg.declare(metadata i32* %pangolin, metadata !52,
> > metadata !DIExpression()), !dbg !53
> > + store i32 3, i32* %pangolin, align 4, !dbg !53
> > + store i32 16, i32* %dog, align 4, !dbg !54
> > + %0 = load i32, i32* %dog, align 4, !dbg !55
> > + ret i32 %0, !dbg !56
> > +}
> > +
> > +define i32 @f3() #0 !dbg !57 {
> > +entry:
> > + %dog = alloca i32, align 4
> > + %cat = alloca i32, align 4
> > + %pangolin = alloca i32, align 4
> > + call void @llvm.dbg.declare(metadata i32* %dog, metadata !58, metadata
> > !DIExpression()), !dbg !59
> > + store i32 1, i32* %dog, align 4, !dbg !59
> > + call void @llvm.dbg.declare(metadata i32* %cat, metadata !60, metadata
> > !DIExpression()), !dbg !61
> > + store i32 2, i32* %cat, align 4, !dbg !61
> > + call void @llvm.dbg.declare(metadata i32* %pangolin, metadata !62,
> > metadata !DIExpression()), !dbg !63
> > + store i32 3, i32* %pangolin, align 4, !dbg !63
> > + store i32 16, i32* %dog, align 4, !dbg !64
> > + %0 = load i32, i32* %dog, align 4, !dbg !65
> > + ret i32 %0, !dbg !66
> > +}
> > +
> > +define i32 @main() #0 !dbg !67 {
> > +entry:
> > + %retval = alloca i32, align 4
> > + %a = alloca i32, align 4
> > + store i32 0, i32* %retval, align 4
> > + call void @llvm.dbg.declare(metadata i32* %a, metadata !68, metadata
> > !DIExpression()), !dbg !69
> > + store i32 4, i32* %a, align 4, !dbg !69
> > + %call = call i32 @f1() #2, !dbg !70
> > + %call1 = call i32 @f2() #2, !dbg !71
> > + %call2 = call i32 @f3() #2, !dbg !72
> > + ret i32 0, !dbg !73
> > +}
> > +
> > +; CHECK [[UNIT:![0-9]+]] = distinct !DICompileUnit
> > +; CHECK-SAME: file: [[FILE:![0-9]+]],
> > +; CHECK-SAME: producer: "machine-outliner",
> > +; CHECK-SAME: isOptimized: true, runtimeVersion: 0, emissionKind:
> NoDebug
> > +
> > +; CHECK: distinct !DISubprogram(name: "OUTLINED_FUNCTION_1",
> > +; CHECK-SAME: scope: [[FILE]],
> > +; CHECK-SAME: file: [[FILE]],
> > +; CHECK-SAME: type: [[TYPE:![0-9]+]],
> > +; CHECK-SAME: isLocal: false,
> > +; CHECK-SAME: isDefinition: true,
> > +; CHECK-SAME: flags: DIFlagArtificial,
> > +; CHECK-SAME: isOptimized: true,
> > +; CHECK-SAME: unit: [[UNIT]],
> > +; CHECK-SAME: variables: [[VARS:![0-9]+]]
> > +
> > +; CHECK: distinct !DISubprogram(name: "OUTLINED_FUNCTION_1",
> > +; CHECK-SAME: scope: [[FILE]],
> > +; CHECK-SAME: file: [[FILE]],
> > +; CHECK-SAME: type: [[TYPE]],
> > +; CHECK-SAME: isLocal: false,
> > +; CHECK-SAME: isDefinition: true,
> > +; CHECK-SAME: flags: DIFlagArtificial,
> > +; CHECK-SAME: isOptimized: true,
> > +; CHECK-SAME: unit: [[UNIT]],
> > +; CHECK-SAME: variables: [[VARS]]
> > +
> > +attributes #0 = { noinline noredzone nounwind optnone ssp uwtable "no-
> > frame-pointer-elim"="true" }
> > +attributes #1 = { nounwind readnone speculatable }
> > +attributes #2 = { noredzone }
> > +
> > +!llvm.dbg.cu = !{!0}
> > +!llvm.module.flags = !{!3, !4, !5, !6}
> > +!llvm.ident = !{!7}
> > +
> > +!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer:
> > "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug,
> > enums: !2)
> > +!1 = !DIFile(filename: "test.c", directory: "/")
> > +!2 = !{}
> > +!3 = !{i32 2, !"Dwarf Version", i32 4}
> > +!4 = !{i32 2, !"Debug Info Version", i32 3}
> > +!5 = !{i32 1, !"wchar_size", i32 4}
> > +!6 = !{i32 7, !"PIC Level", i32 2}
> > +!7 = !{!"clang"}
> > +!8 = distinct !DISubprogram(name: "f6", scope: !1, file: !1, line: 3,
> > type: !9, isLocal: false, isDefinition: true, scopeLine: 3, isOptimized:
> > false, unit: !0, variables: !2)
> > +!9 = !DISubroutineType(types: !10)
> > +!10 = !{null}
> > +!11 = !DILocalVariable(name: "dog", scope: !8, file: !1, line: 4, type:
> > !12)
> > +!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
> > +!13 = !DILocation(line: 4, column: 16, scope: !8)
> > +!14 = !DILocalVariable(name: "cat", scope: !8, file: !1, line: 5, type:
> > !12)
> > +!15 = !DILocation(line: 5, column: 16, scope: !8)
> > +!16 = !DILocalVariable(name: "pangolin", scope: !8, file: !1, line: 6,
> > type: !12)
> > +!17 = !DILocation(line: 6, column: 16, scope: !8)
> > +!18 = !DILocation(line: 7, column: 1, scope: !8)
> > +!19 = distinct !DISubprogram(name: "f5", scope: !1, file: !1, line: 9,
> > type: !9, isLocal: false, isDefinition: true, scopeLine: 9, isOptimized:
> > false, unit: !0, variables: !2)
> > +!20 = !DILocalVariable(name: "dog", scope: !19, file: !1, line: 10,
> type:
> > !12)
> > +!21 = !DILocation(line: 10, column: 16, scope: !19)
> > +!22 = !DILocalVariable(name: "cat", scope: !19, file: !1, line: 11,
> type:
> > !12)
> > +!23 = !DILocation(line: 11, column: 16, scope: !19)
> > +!24 = !DILocalVariable(name: "pangolin", scope: !19, file: !1, line: 12,
> > type: !12)
> > +!25 = !DILocation(line: 12, column: 16, scope: !19)
> > +!26 = !DILocation(line: 13, column: 1, scope: !19)
> > +!27 = distinct !DISubprogram(name: "f4", scope: !1, file: !1, line: 15,
> > type: !9, isLocal: false, isDefinition: true, scopeLine: 15, isOptimized:
> > false, unit: !0, variables: !2)
> > +!28 = !DILocalVariable(name: "dog", scope: !27, file: !1, line: 16,
> type:
> > !12)
> > +!29 = !DILocation(line: 16, column: 16, scope: !27)
> > +!30 = !DILocalVariable(name: "cat", scope: !27, file: !1, line: 17,
> type:
> > !12)
> > +!31 = !DILocation(line: 17, column: 16, scope: !27)
> > +!32 = !DILocalVariable(name: "pangolin", scope: !27, file: !1, line: 18,
> > type: !12)
> > +!33 = !DILocation(line: 18, column: 16, scope: !27)
> > +!34 = !DILocation(line: 19, column: 1, scope: !27)
> > +!35 = distinct !DISubprogram(name: "f1", scope: !1, file: !1, line: 21,
> > type: !36, isLocal: false, isDefinition: true, scopeLine: 21,
> isOptimized:
> > false, unit: !0, variables: !2)
> > +!36 = !DISubroutineType(types: !37)
> > +!37 = !{!12}
> > +!38 = !DILocalVariable(name: "dog", scope: !35, file: !1, line: 22,
> type:
> > !12)
> > +!39 = !DILocation(line: 22, column: 16, scope: !35)
> > +!40 = !DILocalVariable(name: "cat", scope: !35, file: !1, line: 23,
> type:
> > !12)
> > +!41 = !DILocation(line: 23, column: 16, scope: !35)
> > +!42 = !DILocalVariable(name: "pangolin", scope: !35, file: !1, line: 24,
> > type: !12)
> > +!43 = !DILocation(line: 24, column: 16, scope: !35)
> > +!44 = !DILocation(line: 25, column: 7, scope: !35)
> > +!45 = !DILocation(line: 26, column: 10, scope: !35)
> > +!46 = !DILocation(line: 26, column: 3, scope: !35)
> > +!47 = distinct !DISubprogram(name: "f2", scope: !1, file: !1, line: 29,
> > type: !36, isLocal: false, isDefinition: true, scopeLine: 29,
> isOptimized:
> > false, unit: !0, variables: !2)
> > +!48 = !DILocalVariable(name: "dog", scope: !47, file: !1, line: 30,
> type:
> > !12)
> > +!49 = !DILocation(line: 30, column: 16, scope: !47)
> > +!50 = !DILocalVariable(name: "cat", scope: !47, file: !1, line: 31,
> type:
> > !12)
> > +!51 = !DILocation(line: 31, column: 16, scope: !47)
> > +!52 = !DILocalVariable(name: "pangolin", scope: !47, file: !1, line: 32,
> > type: !12)
> > +!53 = !DILocation(line: 32, column: 16, scope: !47)
> > +!54 = !DILocation(line: 33, column: 7, scope: !47)
> > +!55 = !DILocation(line: 34, column: 10, scope: !47)
> > +!56 = !DILocation(line: 34, column: 3, scope: !47)
> > +!57 = distinct !DISubprogram(name: "f3", scope: !1, file: !1, line: 37,
> > type: !36, isLocal: false, isDefinition: true, scopeLine: 37,
> isOptimized:
> > false, unit: !0, variables: !2)
> > +!58 = !DILocalVariable(name: "dog", scope: !57, file: !1, line: 38,
> type:
> > !12)
> > +!59 = !DILocation(line: 38, column: 16, scope: !57)
> > +!60 = !DILocalVariable(name: "cat", scope: !57, file: !1, line: 39,
> type:
> > !12)
> > +!61 = !DILocation(line: 39, column: 16, scope: !57)
> > +!62 = !DILocalVariable(name: "pangolin", scope: !57, file: !1, line: 40,
> > type: !12)
> > +!63 = !DILocation(line: 40, column: 16, scope: !57)
> > +!64 = !DILocation(line: 41, column: 7, scope: !57)
> > +!65 = !DILocation(line: 42, column: 10, scope: !57)
> > +!66 = !DILocation(line: 42, column: 3, scope: !57)
> > +!67 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line:
> 45,
> > type: !36, isLocal: false, isDefinition: true, scopeLine: 45, flags:
> > DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
> > +!68 = !DILocalVariable(name: "a", scope: !67, file: !1, line: 46, type:
> > !12)
> > +!69 = !DILocation(line: 46, column: 16, scope: !67)
> > +!70 = !DILocation(line: 47, column: 3, scope: !67)
> > +!71 = !DILocation(line: 48, column: 3, scope: !67)
> > +!72 = !DILocation(line: 49, column: 3, scope: !67)
> > +!73 = !DILocation(line: 51, column: 3, scope: !67)
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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