[PATCH] D110332: [DebugInfo] Limit the size of DIExpressions that we will salvage up to
Stephen Tozer via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 15 09:36:00 PDT 2021
This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGf5ed223b0fd0: [DebugInfo] Limit the size of DIExpressions that we will salvage up to (authored by StephenTozer).
Changed prior to commit:
https://reviews.llvm.org/D110332?vs=379481&id=380040#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D110332/new/
https://reviews.llvm.org/D110332
Files:
llvm/lib/Transforms/Utils/Local.cpp
llvm/test/DebugInfo/salvage-limit-expr-size.ll
Index: llvm/test/DebugInfo/salvage-limit-expr-size.ll
===================================================================
--- /dev/null
+++ llvm/test/DebugInfo/salvage-limit-expr-size.ll
@@ -0,0 +1,47 @@
+; RUN: opt %s -dce -S | FileCheck %s
+
+;; Tests that a DIExpression will only be salvaged up to a certain length, and
+;; will produce an undef value if an expression would need to exceed that length.
+
+define i32 @"?multiply@@YAHHH at Z"(i32 %a, i32 %b) !dbg !8 {
+entry:
+ %add.1 = add nsw i32 %a, 5, !dbg !14
+ %add.2 = add nsw i32 %a, %b, !dbg !14
+ ;; These expressions should salvage successfully, up to exactly 128 elements.
+ ; CHECK: call void @llvm.dbg.value(metadata i32 %a, metadata ![[VAR_C:[0-9]+]]
+ ; CHECK-NEXT: call void @llvm.dbg.value(metadata !DIArgList(i32 %a, i32 %b), metadata ![[VAR_C]]
+ call void @llvm.dbg.value(metadata i32 %add.1, metadata !12, metadata !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_stack_value)), !dbg !13
+ call void @llvm.dbg.value(metadata i32 %add.2, metadata !12, metadata !DIExpression(DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_stack_value)), !dbg !13
+ ;; These expressions should be set undef, as they would salvage up to exactly 129 elements.
+ ; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 undef, metadata ![[VAR_C]]
+ ; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 undef, metadata ![[VAR_C]]
+ call void @llvm.dbg.value(metadata i32 %add.1, metadata !12, metadata !DIExpression(DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_stack_value)), !dbg !13
+ call void @llvm.dbg.value(metadata i32 %add.2, metadata !12, metadata !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_plus_uconst, 1, DW_OP_stack_value)), !dbg !13
+ %mul = mul nsw i32 %a, %b, !dbg !15
+ ret i32 %mul, !dbg !15
+}
+
+; CHECK: ![[VAR_C]] = !DILocalVariable(name: "c"
+
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 11.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "test.cpp", directory: "/")
+!2 = !{}
+!3 = !{i32 2, !"CodeView", i32 1}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 2}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!7 = !{!"clang version 11.0.0"}
+!8 = distinct !DISubprogram(name: "multiply", linkageName: "?multiply@@YAHHH at Z", scope: !1, file: !1, line: 1, type: !9, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!9 = !DISubroutineType(types: !10)
+!10 = !{!11, !11, !11}
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !DILocalVariable(name: "c", scope: !8, file: !1, line: 2, type: !11)
+!13 = !DILocation(line: 0, scope: !8)
+!14 = !DILocation(line: 2, scope: !8)
+!15 = !DILocation(line: 3, scope: !8)
Index: llvm/lib/Transforms/Utils/Local.cpp
===================================================================
--- llvm/lib/Transforms/Utils/Local.cpp
+++ llvm/lib/Transforms/Utils/Local.cpp
@@ -1733,9 +1733,11 @@
void llvm::salvageDebugInfoForDbgValues(
Instruction &I, ArrayRef<DbgVariableIntrinsic *> DbgUsers) {
- // This is an arbitrary chosen limit on the maximum number of values we can
- // salvage up to in a DIArgList, used for performance reasons.
+ // These are arbitrary chosen limits on the maximum number of values and the
+ // maximum size of a debug expression we can salvage up to, used for
+ // performance reasons.
const unsigned MaxDebugArgs = 16;
+ const unsigned MaxExpressionSize = 128;
bool Salvaged = false;
for (auto *DII : DbgUsers) {
@@ -1772,9 +1774,10 @@
break;
DII->replaceVariableLocationOp(&I, Op0);
- if (AdditionalValues.empty()) {
+ bool IsValidSalvageExpr = SalvagedExpr->getNumElements() <= MaxExpressionSize;
+ if (AdditionalValues.empty() && IsValidSalvageExpr) {
DII->setExpression(SalvagedExpr);
- } else if (isa<DbgValueInst>(DII) &&
+ } else if (isa<DbgValueInst>(DII) && IsValidSalvageExpr &&
DII->getNumVariableLocationOps() + AdditionalValues.size() <=
MaxDebugArgs) {
DII->addVariableLocationOps(AdditionalValues, SalvagedExpr);
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