[DebugInfo][OPT] Fixing a couple of DI duplication bugs of CloneModule
As demonstrated by the regression tests added in this patch, the
following cases are valid cases:
1. A Function with no DISubprogram attached, but various debug info
related to its instructions, coming, for instance, from an inlined
function, also defined somewhere else in the same module;
2. ... or coming exclusively from the functions inlined and eliminated
from the module entirely.
The ValueMap shared between CloneFunctionInto calls within CloneModule
needs to contain identity mappings for all of the DISubprogram's to
prevent them from being duplicated by MapMetadata / RemapInstruction
calls, this is achieved via DebugInfoFinder collecting all the
DISubprogram's. However, CloneFunctionInto was missing calls into
DebugInfoFinder for functions w/o DISubprogram's attached, but still
referring DISubprogram's from within (case 1). This patch fixes that.
The fix above, however, exposes another issue: if a module contains a
DISubprogram referenced only indirectly from other debug info
metadata, but not attached to any Function defined within the module
(case 2), cloning such a module causes a DICompileUnit duplication: it
will be moved in indirecty via a DISubprogram by DebugInfoFinder first
(because of the first bug fix described above), without being
self-mapped within the shared ValueMap, and then will be copied during
named metadata cloning. So this patch makes sure DebugInfoFinder
visits DICompileUnit's referenced from DISubprogram's as it goes w/o
re-processing llvm.dbg.cu list over and over again for every function
cloned, and makes sure that CloneFunctionInto self-maps
DICompileUnit's referenced from the entire function, not just its own
DISubprogram attached that may also be missing.
The most convenient way of tesing CloneModule I found is to rely on
CloneModule call from `opt -run-twice`, instead of writing tedious
unit tests. That feature has a couple of properties that makes it hard
to use for this purpose though:
1. CloneModule doesn't copy source filename, making `opt -run-twice`
report it as a difference.
2. `opt -run-twice` does the second run on the original module, not
its clone, making the result of cloning completely invisible in opt's
actual output with and without `-run-twice` both, which directly
contradicts `opt -run-twice`s own error message.
This patch fixes this as well.
Reviewed By: aprantl
Reviewers: loladiro, GorNishanov, espindola, echristo, dexonsmith
Subscribers: vsk, debug-info, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D45593
llvm-svn: 330069
2018-04-14 05:22:24 +08:00
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; RUN: opt -run-twice -verify -S -o - %s | FileCheck %s
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; The ValueMap shared between CloneFunctionInto calls within CloneModule needs
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; to contain identity mappings for all of the DISubprogram's to prevent them
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; from being duplicated by MapMetadata / RemapInstruction calls, this is
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; achieved via DebugInfoFinder collecting all the DISubprogram's. However,
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; CloneFunctionInto was missing calls into DebugInfoFinder for functions w/o
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; DISubprogram's attached, but still referring DISubprogram's from within.
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;
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; This is to make sure we don't regress on that.
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; Derived from the following C-snippet
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;
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; int inlined(int j);
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; __attribute__((nodebug)) int nodebug(int k) { return inlined(k); }
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; __attribute__((always_inline)) int inlined(int j) { return j * 2; }
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;
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; compiled with `clang -O1 -g3 -emit-llvm -S` by removing
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;
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; call void @llvm.dbg.value(metadata i32 %k, metadata !8, metadata !DIExpression()), !dbg !14
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;
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; line from @nodebug function.
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; The @llvm.dbg.value call is manually removed from @nodebug as not having
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; it there also may cause an incorrect remapping of the call in a case of a
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; regression, not just a duplication of a DISubprogram. Namely, the call's
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; metadata !8 2nd argument and the !dbg !14 debug location may get remapped
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; to reference different copies of the DISubprogram, which is verified by IR
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; Verifier, while having DISubprogram duplicates is not.
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; CHECK: DISubprogram
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; CHECK-NOT: DISubprogram
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source_filename = "clone-module.c"
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx"
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; Function Attrs: nounwind readnone ssp uwtable
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define i32 @nodebug(i32 %k) local_unnamed_addr #0 {
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entry:
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%mul.i = shl nsw i32 %k, 1, !dbg !15
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ret i32 %mul.i
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}
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; Function Attrs: alwaysinline nounwind readnone ssp uwtable
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define i32 @inlined(i32 %j) local_unnamed_addr #1 !dbg !9 {
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entry:
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call void @llvm.dbg.value(metadata i32 %j, metadata !8, metadata !DIExpression()), !dbg !14
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%mul = shl nsw i32 %j, 1, !dbg !15
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ret i32 %mul, !dbg !16
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}
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; Function Attrs: nounwind readnone speculatable
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declare void @llvm.dbg.value(metadata, metadata, metadata) #2
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attributes #0 = { nounwind readnone ssp uwtable }
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attributes #1 = { alwaysinline nounwind readnone ssp uwtable }
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attributes #2 = { nounwind readnone speculatable }
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4, !5, !6}
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!llvm.ident = !{!7}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 7.0.0 (https://git.llvm.org/git/clang.git/ 195459d046e795f5952f7d2121e505eeb59c5574) (https://git.llvm.org/git/llvm.git/ 69ec7d5667e9928db8435bfbee0da151c85a91c9)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
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!1 = !DIFile(filename: "clone-module.c", directory: "/somewhere")
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!2 = !{}
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{i32 1, !"wchar_size", i32 4}
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!6 = !{i32 7, !"PIC Level", i32 2}
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!7 = !{!"clang version 7.0.0 (https://git.llvm.org/git/clang.git/ 195459d046e795f5952f7d2121e505eeb59c5574) (https://git.llvm.org/git/llvm.git/ 69ec7d5667e9928db8435bfbee0da151c85a91c9)"}
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!8 = !DILocalVariable(name: "j", arg: 1, scope: !9, file: !1, line: 3, type: !12)
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[DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label.
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
2018-05-09 10:40:45 +08:00
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!9 = distinct !DISubprogram(name: "inlined", scope: !1, file: !1, line: 3, type: !10, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !13)
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[DebugInfo][OPT] Fixing a couple of DI duplication bugs of CloneModule
As demonstrated by the regression tests added in this patch, the
following cases are valid cases:
1. A Function with no DISubprogram attached, but various debug info
related to its instructions, coming, for instance, from an inlined
function, also defined somewhere else in the same module;
2. ... or coming exclusively from the functions inlined and eliminated
from the module entirely.
The ValueMap shared between CloneFunctionInto calls within CloneModule
needs to contain identity mappings for all of the DISubprogram's to
prevent them from being duplicated by MapMetadata / RemapInstruction
calls, this is achieved via DebugInfoFinder collecting all the
DISubprogram's. However, CloneFunctionInto was missing calls into
DebugInfoFinder for functions w/o DISubprogram's attached, but still
referring DISubprogram's from within (case 1). This patch fixes that.
The fix above, however, exposes another issue: if a module contains a
DISubprogram referenced only indirectly from other debug info
metadata, but not attached to any Function defined within the module
(case 2), cloning such a module causes a DICompileUnit duplication: it
will be moved in indirecty via a DISubprogram by DebugInfoFinder first
(because of the first bug fix described above), without being
self-mapped within the shared ValueMap, and then will be copied during
named metadata cloning. So this patch makes sure DebugInfoFinder
visits DICompileUnit's referenced from DISubprogram's as it goes w/o
re-processing llvm.dbg.cu list over and over again for every function
cloned, and makes sure that CloneFunctionInto self-maps
DICompileUnit's referenced from the entire function, not just its own
DISubprogram attached that may also be missing.
The most convenient way of tesing CloneModule I found is to rely on
CloneModule call from `opt -run-twice`, instead of writing tedious
unit tests. That feature has a couple of properties that makes it hard
to use for this purpose though:
1. CloneModule doesn't copy source filename, making `opt -run-twice`
report it as a difference.
2. `opt -run-twice` does the second run on the original module, not
its clone, making the result of cloning completely invisible in opt's
actual output with and without `-run-twice` both, which directly
contradicts `opt -run-twice`s own error message.
This patch fixes this as well.
Reviewed By: aprantl
Reviewers: loladiro, GorNishanov, espindola, echristo, dexonsmith
Subscribers: vsk, debug-info, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D45593
llvm-svn: 330069
2018-04-14 05:22:24 +08:00
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!10 = !DISubroutineType(types: !11)
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!11 = !{!12, !12}
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!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!13 = !{!8}
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!14 = !DILocation(line: 3, column: 48, scope: !9)
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!15 = !DILocation(line: 3, column: 62, scope: !9)
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!16 = !DILocation(line: 3, column: 53, scope: !9)
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