[llvm] r239380 - [DWARF] Fix a few corner cases in expression emission
Keno Fischer
kfischer at college.harvard.edu
Mon Jun 8 18:54:00 PDT 2015
Author: kfischer
Date: Mon Jun 8 20:53:59 2015
New Revision: 239380
URL: http://llvm.org/viewvc/llvm-project?rev=239380&view=rev
Log:
[DWARF] Fix a few corner cases in expression emission
Summary: I noticed an object file with `DW_OP_reg4 DW_OP_breg4 0` as a DWARF expression,
which I traced to a missing break (and `++I`) in this code snippet.
While I was at it, I also added support for a few other corner cases
along the same lines that I could think of.
Test Plan: Hand-crafted test case to exercises these cases is included.
Reviewers: echristo, dblaikie, aprantl
Reviewed By: aprantl
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10302
Added:
llvm/trunk/test/DebugInfo/expressions.ll
Modified:
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=239380&r1=239379&r2=239380&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Mon Jun 8 20:53:59 2015
@@ -1562,6 +1562,8 @@ void DwarfDebug::emitDebugLoc() {
Asm->OutStreamer->EmitLabel(List.Label);
const DwarfCompileUnit *CU = List.CU;
for (const auto &Entry : DebugLocs.getEntries(List)) {
+ if (Entry.BeginSym == Entry.EndSym)
+ continue;
// Set up the range. This range is relative to the entry point of the
// compile unit. This is a hard coded 0 for low_pc when we're emitting
// ranges, or the DW_AT_low_pc on the compile unit otherwise.
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp?rev=239380&r1=239379&r2=239380&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp Mon Jun 8 20:53:59 2015
@@ -65,6 +65,11 @@ void DwarfExpression::AddShr(unsigned Sh
EmitOp(dwarf::DW_OP_shr);
}
+void DwarfExpression::AddOpStackValue() {
+ if (DwarfVersion >= 4)
+ EmitOp(dwarf::DW_OP_stack_value);
+}
+
bool DwarfExpression::AddMachineRegIndirect(unsigned MachineReg, int Offset) {
if (isFrameRegister(MachineReg)) {
// If variable offset is based in frame register then use fbreg.
@@ -172,16 +177,14 @@ void DwarfExpression::AddSignedConstant(
// value, so the producers and consumers started to rely on heuristics
// to disambiguate the value vs. location status of the expression.
// See PR21176 for more details.
- if (DwarfVersion >= 4)
- EmitOp(dwarf::DW_OP_stack_value);
+ AddOpStackValue();
}
void DwarfExpression::AddUnsignedConstant(unsigned Value) {
EmitOp(dwarf::DW_OP_constu);
EmitUnsigned(Value);
// cf. comment in DwarfExpression::AddSignedConstant().
- if (DwarfVersion >= 4)
- EmitOp(dwarf::DW_OP_stack_value);
+ AddOpStackValue();
}
static unsigned getOffsetOrZero(unsigned OffsetInBits,
@@ -212,15 +215,30 @@ bool DwarfExpression::AddMachineRegExpre
getOffsetOrZero(OffsetInBits, PieceOffsetInBits));
}
case dwarf::DW_OP_plus: {
- // [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].
auto N = I.getNext();
+ unsigned Offset = I->getArg(0);
+ // First combine all DW_OP_plus until we hit either a DW_OP_deref or a
+ // DW_OP_bit_piece
+ while (N != E && N->getOp() == dwarf::DW_OP_plus) {
+ Offset += N->getArg(0);
+ ++I;
+ N = I.getNext();
+ }
if (N != E && N->getOp() == dwarf::DW_OP_deref) {
- unsigned Offset = I->getArg(0);
+ // [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].
ValidReg = AddMachineRegIndirect(MachineReg, Offset);
std::advance(I, 2);
- break;
- } else
- ValidReg = AddMachineRegPiece(MachineReg);
+ } else {
+ assert ((N == E) || (N->getOp() == dwarf::DW_OP_bit_piece));
+ if (Offset == 0) {
+ ValidReg = AddMachineRegPiece(MachineReg);
+ } else {
+ ValidReg = AddMachineRegIndirect(MachineReg, Offset);
+ AddOpStackValue();
+ }
+ ++I;
+ }
+ break;
}
case dwarf::DW_OP_deref: {
// [DW_OP_reg,DW_OP_deref] --> [DW_OP_breg].
@@ -237,6 +255,7 @@ bool DwarfExpression::AddMachineRegExpre
// Emit remaining elements of the expression.
AddExpression(I, E, PieceOffsetInBits);
+
return true;
}
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h?rev=239380&r1=239379&r2=239380&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h Mon Jun 8 20:53:59 2015
@@ -83,6 +83,9 @@ public:
bool AddMachineRegPiece(unsigned MachineReg, unsigned PieceSizeInBits = 0,
unsigned PieceOffsetInBits = 0);
+ /// Emit a DW_OP_stack_value
+ void AddOpStackValue();
+
/// Emit a signed constant.
void AddSignedConstant(int Value);
/// Emit an unsigned constant.
Added: llvm/trunk/test/DebugInfo/expressions.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/expressions.ll?rev=239380&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/expressions.ll (added)
+++ llvm/trunk/test/DebugInfo/expressions.ll Mon Jun 8 20:53:59 2015
@@ -0,0 +1,110 @@
+; REQUIRES: object-emission
+; RUN: %llc_dwarf -mtriple x86_64-apple-darwin14.0.0-elf -filetype=obj %s -o %t
+; RUN: %llc_dwarf -mtriple x86_64-apple-darwin14.0.0-elf -O0 -filetype=obj %s -o %t0
+; RUN: llvm-dwarfdump -debug-dump=loc %t | FileCheck %s
+; RUN: llvm-dwarfdump -debug-dump=loc %t0 | FileCheck -check-prefix CHECK-O0 %s
+
+; CHECK: 0x00000000: Beginning address offset: 0x0000000000000000
+; CHECK: Ending address offset: 0x[[END:[0-9a-f]+]]
+; CHECK: Location description:
+; CHECK-NOT: 75 00 55
+; CHECK-SAME: 55
+; CHECK: 0x00000023: Beginning address offset: 0x0000000000000000
+; CHECK: Ending address offset: 0x{{.*}}[[END]]
+; CHECK: Location description: 75 08 9f
+; CHECK: 0x00000048: Beginning address offset: 0x0000000000000000
+; CHECK: Ending address offset: 0x{{.*}}[[END]]
+; CHECK: Location description: 75 10 9f
+; CHECK: 0x0000006d: Beginning address offset: 0x0000000000000000
+; CHECK: Ending address offset: 0x{{.*}}[[END]]
+; CHECK: Location description: 75 18
+
+
+; CHECK-O0: 0x00000000: Beginning address offset: 0x0000000000000000
+; CHECK-O0: Ending address offset: 0x000000000000001b
+; CHECK-O0: Location description: 55
+; CHECK-O0: Beginning address offset: 0x000000000000001b
+; CHECK-O0: Ending address offset: 0x0000000000000024
+; CHECK-O0: Location description: 54
+; CHECK-O0: Beginning address offset: 0x0000000000000024
+; CHECK-O0: Ending address offset: 0x0000000000000025
+; CHECK-O0: Location description: 77 78 23 00
+; CHECK-O0: 0x0000004c: Beginning address offset: 0x0000000000000000
+; CHECK-O0: Ending address offset: 0x000000000000001b
+; CHECK-O0: Location description: 75 08 9f
+; CHECK-O0: Beginning address offset: 0x000000000000001b
+; CHECK-O0: Ending address offset: 0x0000000000000024
+; CHECK-O0: Location description: 74 08 9f
+; CHECK-O0: Beginning address offset: 0x0000000000000024
+; CHECK-O0: Ending address offset: 0x0000000000000025
+; CHECK-O0: Location description: 77 78 23 08
+; CHECK-O0: 0x0000009c: Beginning address offset: 0x0000000000000000
+; CHECK-O0: Ending address offset: 0x000000000000001b
+; CHECK-O0: Location description: 75 10 9f
+; CHECK-O0: Beginning address offset: 0x000000000000001b
+; CHECK-O0: Ending address offset: 0x0000000000000024
+; CHECK-O0: Location description: 74 10 9f
+; CHECK-O0: Beginning address offset: 0x0000000000000024
+; CHECK-O0: Ending address offset: 0x0000000000000025
+; CHECK-O0: Location description: 77 78 23 08 23 08
+; CHECK-O0: 0x000000ee: Beginning address offset: 0x0000000000000000
+; CHECK-O0: Ending address offset: 0x000000000000001b
+; CHECK-O0: Location description: 75 18
+; CHECK-O0: Beginning address offset: 0x000000000000001b
+; CHECK-O0: Ending address offset: 0x0000000000000024
+; CHECK-O0: Location description: 74 18
+; CHECK-O0: Beginning address offset: 0x0000000000000024
+; CHECK-O0: Ending address offset: 0x0000000000000025
+; CHECK-O0: Location description: 77 78 23 10 23 08 06
+
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #0
+
+define float @foo(float* %args, float *%args2)
+{
+ call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !11, metadata !12), !dbg !19
+ call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !13, metadata !14), !dbg !19
+ call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !15, metadata !16), !dbg !19
+ call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !17, metadata !18), !dbg !19
+ %a = load float, float* %args, !dbg !19
+ %bptr = getelementptr float, float* %args, i32 1, !dbg !19
+ %b = load float, float* %bptr, !dbg !19
+ %cptr = getelementptr float, float* %args, i32 2, !dbg !19
+ %c = load float, float* %cptr, !dbg !19
+ %dptr = getelementptr float, float* %args, i32 3, !dbg !19
+ %d = load float, float* %dptr, !dbg !19
+ %ret1 = fadd float %a, %b, !dbg !19
+ %ret2 = fadd float %c, %d, !dbg !19
+ call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !11, metadata !12), !dbg !19
+ call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !13, metadata !14), !dbg !19
+ call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !15, metadata !16), !dbg !19
+ call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !17, metadata !18), !dbg !19
+ %ret = fsub float %ret1, %ret2, !dbg !19
+ ret float %ret, !dbg !19
+}
+
+attributes #0 = { nounwind readnone }
+
+!llvm.module.flags = !{!0, !1}
+!llvm.dbg.cu = !{!2}
+
+!0 = !{i32 2, !"Dwarf Version", i32 4}
+!1 = !{i32 1, !"Debug Info Version", i32 3}
+
+!2 = !DICompileUnit(language: DW_LANG_C89, file: !3, producer: "byHand", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !4, retainedTypes: !4, subprograms: !5, globals: !4, imports: !4)
+!3 = !DIFile(filename: "expressions", directory: ".")
+!4 = !{}
+!5 = !{!6}
+!6 = !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !3, type: !7, isLocal: false, isDefinition: true, isOptimized: true, function: float (float*, float*)* @foo, variables: !4)
+!7 = !DISubroutineType(types: !8)
+!8 = !{!10, !10}
+!9 = !DIBasicType(name: "float", size: 4, align: 4, encoding: DW_ATE_float)
+!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64, align: 64)
+!11 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "a", arg: 1, scope: !6, file: !3, line: 1, type: !10)
+!12 = !DIExpression(DW_OP_plus, 0)
+!13 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "b", arg: 2, scope: !6, file: !3, line: 1, type: !10)
+!14 = !DIExpression(DW_OP_plus, 8)
+!15 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "c", arg: 3, scope: !6, file: !3, line: 1, type: !10)
+!16 = !DIExpression(DW_OP_plus, 8, DW_OP_plus, 8)
+!17 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "d", arg: 4, scope: !6, file: !3, line: 1, type: !9)
+!18 = !DIExpression(DW_OP_plus, 16, DW_OP_plus, 8, DW_OP_deref)
+!19 = !DILocation(line: 1, scope: !6)
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