[llvm] 96a1e6b - [DebugInfo] Replace debug uses in replaceUsesOutsideBlock
via llvm-commits
llvm-commits at lists.llvm.org
Thu Apr 15 08:20:47 PDT 2021
Author: OCHyams
Date: 2021-04-15T16:19:36+01:00
New Revision: 96a1e6b7cf72d9bd625903ea4b441404200383cf
URL: https://github.com/llvm/llvm-project/commit/96a1e6b7cf72d9bd625903ea4b441404200383cf
DIFF: https://github.com/llvm/llvm-project/commit/96a1e6b7cf72d9bd625903ea4b441404200383cf.diff
LOG: [DebugInfo] Replace debug uses in replaceUsesOutsideBlock
Value::replaceUsesOutsideBlock doesn't replace debug uses which leads to an
unnecessary reduction in variable location coverage. Fix this, add a unittest for
it, and add a regression test demonstrating the change through instcombine's
replacedSelectWithOperand.
Reviewed By: djtodoro
Differential Revision: https://reviews.llvm.org/D99169
Added:
llvm/test/DebugInfo/Generic/instcombine-replaced-select-with-operand.ll
Modified:
llvm/lib/IR/Value.cpp
llvm/unittests/IR/ValueTest.cpp
Removed:
################################################################################
diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index 544f4d6450e07..12c238a08cee1 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -33,6 +33,7 @@
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils/Local.h"
#include <algorithm>
using namespace llvm;
@@ -531,6 +532,17 @@ void Value::replaceNonMetadataUsesWith(Value *New) {
doRAUW(New, ReplaceMetadataUses::No);
}
+/// Replace llvm.dbg.* uses of MetadataAsValue(ValueAsMetadata(V)) outside BB
+/// with New.
+static void replaceDbgUsesOutsideBlock(Value *V, Value *New, BasicBlock *BB) {
+ SmallVector<DbgVariableIntrinsic *> DbgUsers;
+ findDbgUsers(DbgUsers, V);
+ for (auto *DVI : DbgUsers) {
+ if (DVI->getParent() != BB)
+ DVI->replaceVariableLocationOp(V, New);
+ }
+}
+
// Like replaceAllUsesWith except it does not handle constants or basic blocks.
// This routine leaves uses within BB.
void Value::replaceUsesOutsideBlock(Value *New, BasicBlock *BB) {
@@ -541,6 +553,7 @@ void Value::replaceUsesOutsideBlock(Value *New, BasicBlock *BB) {
"replaceUses of value with new value of
diff erent type!");
assert(BB && "Basic block that may contain a use of 'New' must be defined\n");
+ replaceDbgUsesOutsideBlock(this, New, BB);
replaceUsesWithIf(New, [BB](Use &U) {
auto *I = dyn_cast<Instruction>(U.getUser());
// Don't replace if it's an instruction in the BB basic block.
diff --git a/llvm/test/DebugInfo/Generic/instcombine-replaced-select-with-operand.ll b/llvm/test/DebugInfo/Generic/instcombine-replaced-select-with-operand.ll
new file mode 100644
index 0000000000000..8251d71ef6436
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/instcombine-replaced-select-with-operand.ll
@@ -0,0 +1,127 @@
+; RUN: opt -instcombine -S %s | FileCheck %s
+
+;; Ensure that debug uses of a select are replaced when the select is replaced
+;; with one of its operands in InstCombine's replacedSelectWithOperand.
+
+;; Based on IR generated from this source, compiled with -O2 -g:
+;;
+;; extern void* glob;
+;; struct Thing {
+;; void *ptr;
+;; void *get() {return ptr;}
+;; };
+;; Thing *two(void *in) {
+;; if ((long)in & 1)
+;; return nullptr;
+;; return static_cast<Thing *>(in);
+;; }
+;; void one() {
+;; if (Thing *a = two(glob))
+;; // Without the fix we lose 'this' (a) in the inlined call below.
+;; glob = a->get();
+;; }
+
+;; Look at the instruction:
+;; %retval.0.i = select i1 %tobool.not.i, %struct.Thing* %2, %struct.Thing* null
+;; Note that %2 is a bitcast of %0.
+;; InstCombine replaces the use of %retval.0.i in if.then with %0 because
+;; if.then is only branched to when retval.0.is not null. Ensure that debug use
+;; of %retval.0.i is also replaced with %0.
+
+; CHECK: if.then:
+; CHECK-NEXT: call void @llvm.dbg.value(metadata i8* %0, metadata ![[THIS:[0-9]+]], metadata !DIExpression())
+; CHECK: ![[THIS]] = !DILocalVariable(name: "this",
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.Thing = type { i8* }
+
+ at glob = external dso_local local_unnamed_addr global i8*, align 8
+
+define dso_local void @_Z3onev() local_unnamed_addr !dbg !29 {
+entry:
+ %0 = load i8*, i8** @glob, align 8, !dbg !35
+ call void @llvm.dbg.value(metadata i8* %0, metadata !22, metadata !DIExpression()), !dbg !40
+ %1 = ptrtoint i8* %0 to i64, !dbg !42
+ %and.i = and i64 %1, 1, !dbg !43
+ %tobool.not.i = icmp eq i64 %and.i, 0, !dbg !42
+ %2 = bitcast i8* %0 to %struct.Thing*, !dbg !44
+ %retval.0.i = select i1 %tobool.not.i, %struct.Thing* %2, %struct.Thing* null, !dbg !44
+ call void @llvm.dbg.value(metadata %struct.Thing* %retval.0.i, metadata !33, metadata !DIExpression()), !dbg !45
+ %tobool.not = icmp eq %struct.Thing* %retval.0.i, null, !dbg !46
+ br i1 %tobool.not, label %if.end, label %if.then, !dbg !47
+
+if.then: ; preds = %entry
+ call void @llvm.dbg.value(metadata %struct.Thing* %retval.0.i, metadata !48, metadata !DIExpression()), !dbg !51
+ %ptr.i = getelementptr inbounds %struct.Thing, %struct.Thing* %retval.0.i, i64 0, i32 0, !dbg !53
+ %3 = load i8*, i8** %ptr.i, align 8, !dbg !53
+ store i8* %3, i8** @glob, align 8, !dbg !56
+ br label %if.end, !dbg !57
+
+if.end: ; preds = %if.then, %entry
+ ret void, !dbg !58
+}
+
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!14, !15, !16}
+!llvm.ident = !{!17}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 13.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "test.cpp", directory: "/")
+!2 = !{}
+!3 = !{!4, !5}
+!4 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed)
+!5 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64)
+!6 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Thing", file: !1, line: 2, size: 64, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTS5Thing")
+!7 = !{!8, !10}
+!8 = !DIDerivedType(tag: DW_TAG_member, name: "ptr", scope: !6, file: !1, line: 3, baseType: !9, size: 64)
+!9 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+!10 = !DISubprogram(name: "get", linkageName: "_ZN5Thing3getEv", scope: !6, file: !1, line: 4, type: !11, scopeLine: 4, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized)
+!11 = !DISubroutineType(types: !12)
+!12 = !{!9, !13}
+!13 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64, flags: DIFlagArtificial | DIFlagObjectPointer)
+!14 = !{i32 7, !"Dwarf Version", i32 4}
+!15 = !{i32 2, !"Debug Info Version", i32 3}
+!16 = !{i32 1, !"wchar_size", i32 4}
+!17 = !{!"clang version 13.0.0"}
+!18 = distinct !DISubprogram(name: "two", linkageName: "_Z3twoPv", scope: !1, file: !1, line: 6, type: !19, scopeLine: 6, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !21)
+!19 = !DISubroutineType(types: !20)
+!20 = !{!5, !9}
+!21 = !{!22}
+!22 = !DILocalVariable(name: "in", arg: 1, scope: !18, file: !1, line: 6, type: !9)
+!23 = !DILocation(line: 0, scope: !18)
+!24 = !DILocation(line: 7, column: 7, scope: !25)
+!25 = distinct !DILexicalBlock(scope: !18, file: !1, line: 7, column: 7)
+!26 = !DILocation(line: 7, column: 16, scope: !25)
+!27 = !DILocation(line: 7, column: 7, scope: !18)
+!28 = !DILocation(line: 10, column: 1, scope: !18)
+!29 = distinct !DISubprogram(name: "one", linkageName: "_Z3onev", scope: !1, file: !1, line: 11, type: !30, scopeLine: 11, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !32)
+!30 = !DISubroutineType(types: !31)
+!31 = !{null}
+!32 = !{!33}
+!33 = !DILocalVariable(name: "a", scope: !34, file: !1, line: 12, type: !5)
+!34 = distinct !DILexicalBlock(scope: !29, file: !1, line: 12, column: 14)
+!35 = !DILocation(line: 12, column: 22, scope: !34)
+!40 = !DILocation(line: 0, scope: !18, inlinedAt: !41)
+!41 = distinct !DILocation(line: 12, column: 18, scope: !34)
+!42 = !DILocation(line: 7, column: 7, scope: !25, inlinedAt: !41)
+!43 = !DILocation(line: 7, column: 16, scope: !25, inlinedAt: !41)
+!44 = !DILocation(line: 7, column: 7, scope: !18, inlinedAt: !41)
+!45 = !DILocation(line: 0, scope: !34)
+!46 = !DILocation(line: 12, column: 14, scope: !34)
+!47 = !DILocation(line: 12, column: 14, scope: !29)
+!48 = !DILocalVariable(name: "this", arg: 1, scope: !49, type: !5, flags: DIFlagArtificial | DIFlagObjectPointer)
+!49 = distinct !DISubprogram(name: "get", linkageName: "_ZN5Thing3getEv", scope: !6, file: !1, line: 4, type: !11, scopeLine: 4, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, declaration: !10, retainedNodes: !50)
+!50 = !{!48}
+!51 = !DILocation(line: 0, scope: !49, inlinedAt: !52)
+!52 = distinct !DILocation(line: 14, column: 15, scope: !34)
+!53 = !DILocation(line: 4, column: 23, scope: !49, inlinedAt: !52)
+!56 = !DILocation(line: 14, column: 10, scope: !34)
+!57 = !DILocation(line: 14, column: 5, scope: !34)
+!58 = !DILocation(line: 15, column: 1, scope: !29)
+!59 = !DILocation(line: 0, scope: !49)
+!60 = !DILocation(line: 4, column: 23, scope: !49)
+!61 = !DILocation(line: 4, column: 16, scope: !49)
diff --git a/llvm/unittests/IR/ValueTest.cpp b/llvm/unittests/IR/ValueTest.cpp
index 0c42e4632e87f..f94eec89ad617 100644
--- a/llvm/unittests/IR/ValueTest.cpp
+++ b/llvm/unittests/IR/ValueTest.cpp
@@ -9,6 +9,7 @@
#include "llvm/IR/Value.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/Function.h"
+#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ModuleSlotTracker.h"
@@ -247,4 +248,68 @@ TEST(ValueTest, getLocalSlotDeath) {
}
#endif
+TEST(ValueTest, replaceUsesOutsideBlock) {
+ // Check that Value::replaceUsesOutsideBlock(New, BB) replaces uses outside
+ // BB, including dbg.* uses of MetadataAsValue(ValueAsMetadata(this)).
+ const auto *IR = R"(
+ define i32 @f() !dbg !6 {
+ entry:
+ %a = add i32 0, 1, !dbg !15
+ %b = add i32 0, 2, !dbg !15
+ %c = add i32 %a, 2, !dbg !15
+ call void @llvm.dbg.value(metadata i32 %a, metadata !9, metadata !DIExpression()), !dbg !15
+ br label %exit, !dbg !15
+
+ exit:
+ call void @llvm.dbg.value(metadata i32 %a, metadata !11, metadata !DIExpression()), !dbg !16
+ ret i32 %a, !dbg !16
+ }
+
+ declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+ !llvm.dbg.cu = !{!0}
+ !llvm.module.flags = !{!5}
+
+ !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+ !1 = !DIFile(filename: "test.ll", directory: "/")
+ !2 = !{}
+ !5 = !{i32 2, !"Debug Info Version", i32 3}
+ !6 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !1, line: 1, type: !7, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, retainedNodes: !8)
+ !7 = !DISubroutineType(types: !2)
+ !8 = !{!9, !11}
+ !9 = !DILocalVariable(name: "1", scope: !6, file: !1, line: 1, type: !10)
+ !10 = !DIBasicType(name: "ty32", size: 32, encoding: DW_ATE_signed)
+ !11 = !DILocalVariable(name: "2", scope: !6, file: !1, line: 2, type: !12)
+ !12 = !DIBasicType(name: "ty64", size: 64, encoding: DW_ATE_signed)
+ !15 = !DILocation(line: 1, column: 1, scope: !6)
+ !16 = !DILocation(line: 5, column: 1, scope: !6)
+ )";
+ LLVMContext Ctx;
+ SMDiagnostic Err;
+ std::unique_ptr<Module> M = parseAssemblyString(IR, Err, Ctx);
+ if (!M)
+ Err.print("ValueTest", errs());
+
+ auto GetNext = [](auto *I) { return &*++I->getIterator(); };
+
+ Function *F = M->getFunction("f");
+ // Entry.
+ BasicBlock *Entry = &F->front();
+ Instruction *A = &Entry->front();
+ Instruction *B = GetNext(A);
+ Instruction *C = GetNext(B);
+ auto *EntryDbg = cast<DbgValueInst>(GetNext(C));
+ // Exit.
+ BasicBlock *Exit = GetNext(Entry);
+ auto *ExitDbg = cast<DbgValueInst>(&Exit->front());
+ Instruction *Ret = GetNext(ExitDbg);
+
+ A->replaceUsesOutsideBlock(B, Entry);
+ // These users are in Entry so shouldn't be changed.
+ ASSERT_TRUE(C->getOperand(0) == cast<Value>(A));
+ ASSERT_TRUE(EntryDbg->getValue(0) == cast<Value>(A));
+ // These users are outside Entry so should be changed.
+ ASSERT_TRUE(ExitDbg->getValue(0) == cast<Value>(B));
+ ASSERT_TRUE(Ret->getOperand(0) == cast<Value>(B));
+}
} // end anonymous namespace
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