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[DWARF] Fix a few corner cases in expression emission

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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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239380 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Keno Fischer 2015-06-09 01:53:59 +00:00
parent cfd8f11d48
commit b4863a99c9
4 changed files with 143 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lib/CodeGen/AsmPrinter/DwarfDebug.cpp
View File

@ -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.

37
lib/CodeGen/AsmPrinter/DwarfExpression.cpp
View File

@ -65,6 +65,11 @@ void DwarfExpression::AddShr(unsigned ShiftBy) {
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(int Value) {
// 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::AddMachineRegExpression(const DIExpression *Expr,
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::AddMachineRegExpression(const DIExpression *Expr,
// Emit remaining elements of the expression.
AddExpression(I, E, PieceOffsetInBits);
return true;
}

3
lib/CodeGen/AsmPrinter/DwarfExpression.h
View File

@ -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.

110
test/DebugInfo/expressions.ll Normal file
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@ -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)