RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-23 03:02:36 +01:00
Code Issues Projects Releases Wiki Activity

[Utils] Salvage debug info in recursive inst deletion

Browse Source 
In stage2 -O3 builds of llc, this results in a 0.3% increase in the
number of variables with locations, and a 0.2% increase in the number of
unique source variables overall.

The size of the .debug_loc section of the llc dsym increases by 0.5%.

llvm-svn: 326621
This commit is contained in:
Vedant Kumar 2018-03-02 21:36:35 +00:00
parent c4c4aa758a
commit 50d3f5be42
2 changed files with 62 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
lib/Transforms/Utils/Local.cpp
View File

@ -431,6 +431,7 @@ llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V,
do {
I = DeadInsts.pop_back_val();
salvageDebugInfo(*I);
// Null out all of the instruction's operands to see if any operand becomes
// dead as we go.

61
unittests/Transforms/Utils/Local.cpp
View File

@ -331,3 +331,64 @@ TEST(Local, ConstantFoldTerminator) {
runWithDomTree(*M, "indirectbr_repeated", CFAllTerminators);
runWithDomTree(*M, "indirectbr_unreachable", CFAllTerminators);
}
TEST(Local, SalvageDebugValuesInRecursiveInstDeletion) {
LLVMContext C;
std::unique_ptr<Module> M = parseIR(C,
R"(
define void @f() !dbg !8 {
entry:
%x = add i32 0, 1
%y = add i32 %x, 2
call void @llvm.dbg.value(metadata i32 %x, metadata !11, metadata !DIExpression()), !dbg !13
call void @llvm.dbg.value(metadata i32 %y, metadata !11, metadata !DIExpression()), !dbg !13
ret void, !dbg !14
}
declare void @llvm.dbg.value(metadata, metadata, metadata)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "t2.c", directory: "foo")
!2 = !{}
!3 = !{i32 2, !"Dwarf Version", i32 4}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!8 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 1, type: !9, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, unit: !0, variables: !2)
!9 = !DISubroutineType(types: !10)
!10 = !{null}
!11 = !DILocalVariable(name: "x", scope: !8, file: !1, line: 2, type: !12)
!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!13 = !DILocation(line: 2, column: 7, scope: !8)
!14 = !DILocation(line: 3, column: 1, scope: !8)
)");
auto *GV = M->getNamedValue("f");
ASSERT_TRUE(GV);
auto *F = dyn_cast<Function>(GV);
ASSERT_TRUE(F);
Instruction *Inst = &F->front().front();
Inst = Inst->getNextNode();
ASSERT_TRUE(Inst);
bool Deleted = RecursivelyDeleteTriviallyDeadInstructions(Inst);
ASSERT_TRUE(Deleted);
// The debug values should have been salvaged.
bool FoundX = false;
bool FoundY = false;
uint64_t X_expr[] = {dwarf::DW_OP_plus_uconst, 1, dwarf::DW_OP_stack_value};
uint64_t Y_expr[] = {dwarf::DW_OP_plus_uconst, 1, dwarf::DW_OP_plus_uconst, 2,
dwarf::DW_OP_stack_value};
for (const Instruction &I : F->front()) {
auto DI = dyn_cast<DbgValueInst>(&I);
if (!DI)
continue;
EXPECT_EQ(DI->getVariable()->getName(), "x");
ASSERT_TRUE(cast<ConstantInt>(DI->getValue())->isZero());
ArrayRef<uint64_t> ExprElts = DI->getExpression()->getElements();
if (ExprElts.equals(X_expr))
FoundX = true;
else if (ExprElts.equals(Y_expr))
FoundY = true;
}
ASSERT_TRUE(FoundX);
ASSERT_TRUE(FoundY);
}