[llvm] r316525 - Implement salavageDebugInfo functionality for SelectionDAG.
Adrian Prantl via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 24 15:55:12 PDT 2017
Author: adrian
Date: Tue Oct 24 15:55:12 2017
New Revision: 316525
URL: http://llvm.org/viewvc/llvm-project?rev=316525&view=rev
Log:
Implement salavageDebugInfo functionality for SelectionDAG.
Similar to how llvm::salvagDebugInfo hooks into InstCombine, this adds
a hook that can be invoked before an SDNode that is associated with an
SDDbgValue is erased to capture the effect of the deleted node in a
DIExpression.
The motivating example is an SDDebugValue attached to an ADD operation
that gets folded into a LOAD+OFFSET operation.
rdar://problem/32121503
Added:
llvm/trunk/test/DebugInfo/X86/sdag-salvage-add.ll
Modified:
llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAG.h?rev=316525&r1=316524&r2=316525&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAG.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAG.h Tue Oct 24 15:55:12 2017
@@ -1286,6 +1286,10 @@ public:
return DbgInfo->ByvalParmDbgEnd();
}
+ /// To be invoked on an SDNode that is slated to be erased. This
+ /// function mirrors \c llvm::salvageDebugInfo.
+ void salvageDebugInfo(SDNode &N);
+
void dump() const;
/// Create a stack temporary, suitable for holding the specified value type.
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=316525&r1=316524&r2=316525&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Tue Oct 24 15:55:12 2017
@@ -6978,6 +6978,40 @@ SDDbgValue *SelectionDAG::getFrameIndexD
return new (DbgInfo->getAlloc()) SDDbgValue(Var, Expr, FI, DL, O);
}
+void SelectionDAG::salvageDebugInfo(SDNode &N) {
+ if (!N.getHasDebugValue())
+ return;
+ for (auto DV : GetDbgValues(&N)) {
+ if (DV->isInvalidated())
+ continue;
+ switch (N.getOpcode()) {
+ default:
+ break;
+ case ISD::ADD:
+ SDValue N0 = N.getOperand(0);
+ SDValue N1 = N.getOperand(1);
+ if (!isConstantIntBuildVectorOrConstantInt(N0) &&
+ isConstantIntBuildVectorOrConstantInt(N1)) {
+ uint64_t Offset = N.getConstantOperandVal(1);
+ // Rewrite an ADD constant node into a DIExpression. Since we are
+ // performing arithmetic to compute the variable's *value* in the
+ // DIExpression, we need to mark the expression with a
+ // DW_OP_stack_value.
+ auto *DIExpr = DV->getExpression();
+ DIExpr = DIExpression::prepend(DIExpr, DIExpression::NoDeref, Offset,
+ DIExpression::WithStackValue);
+ SDDbgValue *Clone =
+ getDbgValue(DV->getVariable(), DIExpr, N0.getNode(), N0.getResNo(),
+ DV->isIndirect(), DV->getDebugLoc(), DV->getOrder());
+ DV->setIsInvalidated();
+ AddDbgValue(Clone, N0.getNode(), false);
+ DEBUG(dbgs() << "SALVAGE: Rewriting"; N0.getNode()->dumprFull(this);
+ dbgs() << " into " << *DIExpr << '\n');
+ }
+ }
+ }
+}
+
namespace {
/// RAUWUpdateListener - Helper for ReplaceAllUsesWith - When the node
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp?rev=316525&r1=316524&r2=316525&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Tue Oct 24 15:55:12 2017
@@ -3550,6 +3550,7 @@ void SelectionDAGISel::SelectCodeCommon(
"NodeToMatch was removed partway through selection");
SelectionDAG::DAGNodeDeletedListener NDL(*CurDAG, [&](SDNode *N,
SDNode *E) {
+ CurDAG->salvageDebugInfo(*N);
auto &Chain = ChainNodesMatched;
assert((!E || !is_contained(Chain, N)) &&
"Chain node replaced during MorphNode");
Added: llvm/trunk/test/DebugInfo/X86/sdag-salvage-add.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/sdag-salvage-add.ll?rev=316525&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/sdag-salvage-add.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/sdag-salvage-add.ll Tue Oct 24 15:55:12 2017
@@ -0,0 +1,110 @@
+; RUN: llc -mtriple=x86_64-unknown-unknown -stop-before livedebugvalues %s -o - \
+; RUN: | FileCheck %s
+;
+; Generated at -O1 from:
+; typedef struct {
+; unsigned long long c;
+; } S1;
+; struct S3 {
+; unsigned long long packed;
+; };
+; struct S6 {
+; struct S0 *b;
+; };
+; void f(struct S3 *a3)
+; {
+; struct S4 *s4 = (struct S4 *)(a3->packed + 0x1000UL);
+; struct S6 *myVar = (struct S6 *)s4;
+; struct S0 *b = myVar->b;
+; use(b);
+; }
+;
+; The debug info is attached to the ADD 4096 operation, which doesn't survive
+; instruction selection as it is folded into the load.
+;
+; CHECK: ![[S4:.*]] = !DILocalVariable(name: "s4",
+; CHECK: ![[MYVAR:.*]] = !DILocalVariable(name: "myVar",
+; CHECK: DBG_VALUE debug-use %rax, debug-use _, ![[MYVAR]],
+; CHECK-SAME: !DIExpression(DW_OP_plus_uconst, 4096, DW_OP_stack_value)
+; CHECK-NEXT: DBG_VALUE debug-use %rax, debug-use _, ![[S4]],
+; CHECK-SAME: !DIExpression(DW_OP_plus_uconst, 4096, DW_OP_stack_value)
+; CHECK-NEXT: %rdi = MOV64rm killed %rax, 1, _, 4096, _,
+
+source_filename = "test.c"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.13.0"
+
+%struct.S3 = type { i64 }
+%struct.S4 = type opaque
+%struct.S0 = type opaque
+
+; Function Attrs: noinline nounwind ssp uwtable
+define void @f(%struct.S3* nocapture readonly %a3) local_unnamed_addr #0 !dbg !6 {
+entry:
+ tail call void @llvm.dbg.value(metadata %struct.S3* %a3, metadata !15, metadata !DIExpression()), !dbg !30
+ %packed = getelementptr inbounds %struct.S3, %struct.S3* %a3, i64 0, i32 0, !dbg !31
+ %0 = load i64, i64* %packed, align 8, !dbg !31
+ %add = add i64 %0, 4096, !dbg !37
+ %1 = inttoptr i64 %add to %struct.S4*, !dbg !38
+ tail call void @llvm.dbg.value(metadata %struct.S4* %1, metadata !16, metadata !DIExpression()), !dbg !39
+ tail call void @llvm.dbg.value(metadata %struct.S4* %1, metadata !17, metadata !DIExpression()), !dbg !40
+ %b1 = bitcast %struct.S4* %1 to %struct.S0**, !dbg !41
+ %2 = load %struct.S0*, %struct.S0** %b1, align 8, !dbg !41
+ tail call void @llvm.dbg.value(metadata %struct.S0* %2, metadata !24, metadata !DIExpression()), !dbg !45
+ %call = tail call i32 (%struct.S0*, ...) bitcast (i32 (...)* @use to i32 (%struct.S0*, ...)*)(%struct.S0* %2) #3, !dbg !46
+ ret void, !dbg !47
+}
+
+declare i32 @use(...) local_unnamed_addr
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #2
+
+attributes #0 = { noinline nounwind ssp uwtable }
+attributes #2 = { nounwind readnone speculatable }
+attributes #3 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!25, !26, !27, !28}
+!llvm.ident = !{!29}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 (trunk 316467) (llvm/trunk 316466)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3)
+!1 = !DIFile(filename: "test.c", directory: "/")
+!2 = !{}
+!3 = !{!4, !18}
+!4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !5, size: 64)
+!5 = !DICompositeType(tag: DW_TAG_structure_type, name: "S4", scope: !6, file: !1, line: 20, flags: DIFlagFwdDecl)
+!6 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 18, type: !7, isLocal: false, isDefinition: true, scopeLine: 19, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !14)
+!7 = !DISubroutineType(types: !8)
+!8 = !{null, !9}
+!9 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !10, size: 64)
+!10 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S3", file: !1, line: 5, size: 64, elements: !11)
+!11 = !{!12}
+!12 = !DIDerivedType(tag: DW_TAG_member, name: "packed", scope: !10, file: !1, line: 6, baseType: !13, size: 64)
+!13 = !DIBasicType(name: "long long unsigned int", size: 64, encoding: DW_ATE_unsigned)
+!14 = !{!15, !16, !17, !24}
+!15 = !DILocalVariable(name: "a3", arg: 1, scope: !6, file: !1, line: 18, type: !9)
+!16 = !DILocalVariable(name: "s4", scope: !6, file: !1, line: 20, type: !4)
+!17 = !DILocalVariable(name: "myVar", scope: !6, file: !1, line: 21, type: !18)
+!18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !19, size: 64)
+!19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S6", file: !1, line: 8, size: 64, elements: !20)
+!20 = !{!21}
+!21 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !19, file: !1, line: 9, baseType: !22, size: 64)
+!22 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !23, size: 64)
+!23 = !DICompositeType(tag: DW_TAG_structure_type, name: "S0", file: !1, line: 4, flags: DIFlagFwdDecl)
+!24 = !DILocalVariable(name: "b", scope: !6, file: !1, line: 22, type: !22)
+!25 = !{i32 2, !"Dwarf Version", i32 4}
+!26 = !{i32 2, !"Debug Info Version", i32 3}
+!27 = !{i32 1, !"wchar_size", i32 4}
+!28 = !{i32 7, !"PIC Level", i32 2}
+!29 = !{!"clang version 6.0.0 (trunk 316467) (llvm/trunk 316466)"}
+!30 = !DILocation(line: 18, column: 14, scope: !6)
+!31 = !DILocation(line: 20, column: 37, scope: !6)
+!37 = !DILocation(line: 20, column: 44, scope: !6)
+!38 = !DILocation(line: 20, column: 19, scope: !6)
+!39 = !DILocation(line: 20, column: 14, scope: !6)
+!40 = !DILocation(line: 21, column: 14, scope: !6)
+!41 = !DILocation(line: 22, column: 25, scope: !6)
+!45 = !DILocation(line: 22, column: 14, scope: !6)
+!46 = !DILocation(line: 23, column: 3, scope: !6)
+!47 = !DILocation(line: 24, column: 1, scope: !6)
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