<div dir="ltr">Looks like this might've caused:<br><br><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__lab.llvm.org-3A8011_builders_clang-2Dx86-5F64-2Dubuntu-2Dgdb-2D75_builds_22562&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=mYgvIlV-j3fFDgrYiDAsPzDdMoLWRPYzOdSO9GI1ZFU&s=d57nFIlpCHRj7XfUu8vaVWl-NvqTfgJ91nwmHs70oZk&e=">http://lab.llvm.org:8011/builders/clang-x86_64-ubuntu-gdb-75/builds/22562</a><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jun 8, 2015 at 6:54 PM, Keno Fischer <span dir="ltr"><<a href="mailto:kfischer@college.harvard.edu" target="_blank">kfischer@college.harvard.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: kfischer<br>
Date: Mon Jun 8 20:53:59 2015<br>
New Revision: 239380<br>
<br>
URL: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject-3Frev-3D239380-26view-3Drev&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=mYgvIlV-j3fFDgrYiDAsPzDdMoLWRPYzOdSO9GI1ZFU&s=NIMznrBQO6HA3Vu6V5WYi55ilZXkqVj0lhrmRhMPbP4&e=" target="_blank">http://llvm.org/viewvc/llvm-project?rev=239380&view=rev</a><br>
Log:<br>
[DWARF] Fix a few corner cases in expression emission<br>
<br>
Summary: I noticed an object file with `DW_OP_reg4 DW_OP_breg4 0` as a DWARF expression,<br>
which I traced to a missing break (and `++I`) in this code snippet.<br>
While I was at it, I also added support for a few other corner cases<br>
along the same lines that I could think of.<br>
<br>
Test Plan: Hand-crafted test case to exercises these cases is included.<br>
<br>
Reviewers: echristo, dblaikie, aprantl<br>
<br>
Reviewed By: aprantl<br>
<br>
Subscribers: llvm-commits<br>
<br>
Differential Revision: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__reviews.llvm.org_D10302&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=mYgvIlV-j3fFDgrYiDAsPzDdMoLWRPYzOdSO9GI1ZFU&s=8lc2iIFWLWKRhY8UV8-2AGMa1ZsztNUHJgQqbppHH14&e=" target="_blank">http://reviews.llvm.org/D10302</a><br>
<br>
Added:<br>
llvm/trunk/test/DebugInfo/expressions.ll<br>
Modified:<br>
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp<br>
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp<br>
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h<br>
<br>
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp<br>
URL: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_lib_CodeGen_AsmPrinter_DwarfDebug.cpp-3Frev-3D239380-26r1-3D239379-26r2-3D239380-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=mYgvIlV-j3fFDgrYiDAsPzDdMoLWRPYzOdSO9GI1ZFU&s=9RJ-wC9cZQs6sjJLaIELDx-If6gDjHffOPx_iOZUlMc&e=" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=239380&r1=239379&r2=239380&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)<br>
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Mon Jun 8 20:53:59 2015<br>
@@ -1562,6 +1562,8 @@ void DwarfDebug::emitDebugLoc() {<br>
Asm->OutStreamer->EmitLabel(List.Label);<br>
const DwarfCompileUnit *CU = List.CU;<br>
for (const auto &Entry : DebugLocs.getEntries(List)) {<br>
+ if (Entry.BeginSym == Entry.EndSym)<br>
+ continue;<br>
// Set up the range. This range is relative to the entry point of the<br>
// compile unit. This is a hard coded 0 for low_pc when we're emitting<br>
// ranges, or the DW_AT_low_pc on the compile unit otherwise.<br>
<br>
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp<br>
URL: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_lib_CodeGen_AsmPrinter_DwarfExpression.cpp-3Frev-3D239380-26r1-3D239379-26r2-3D239380-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=mYgvIlV-j3fFDgrYiDAsPzDdMoLWRPYzOdSO9GI1ZFU&s=_cVigoMzig3oiBCoRSVFec_Y7qH5IZhg45KDErwHkCg&e=" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp?rev=239380&r1=239379&r2=239380&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp (original)<br>
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp Mon Jun 8 20:53:59 2015<br>
@@ -65,6 +65,11 @@ void DwarfExpression::AddShr(unsigned Sh<br>
EmitOp(dwarf::DW_OP_shr);<br>
}<br>
<br>
+void DwarfExpression::AddOpStackValue() {<br>
+ if (DwarfVersion >= 4)<br>
+ EmitOp(dwarf::DW_OP_stack_value);<br>
+}<br>
+<br>
bool DwarfExpression::AddMachineRegIndirect(unsigned MachineReg, int Offset) {<br>
if (isFrameRegister(MachineReg)) {<br>
// If variable offset is based in frame register then use fbreg.<br>
@@ -172,16 +177,14 @@ void DwarfExpression::AddSignedConstant(<br>
// value, so the producers and consumers started to rely on heuristics<br>
// to disambiguate the value vs. location status of the expression.<br>
// See PR21176 for more details.<br>
- if (DwarfVersion >= 4)<br>
- EmitOp(dwarf::DW_OP_stack_value);<br>
+ AddOpStackValue();<br>
}<br>
<br>
void DwarfExpression::AddUnsignedConstant(unsigned Value) {<br>
EmitOp(dwarf::DW_OP_constu);<br>
EmitUnsigned(Value);<br>
// cf. comment in DwarfExpression::AddSignedConstant().<br>
- if (DwarfVersion >= 4)<br>
- EmitOp(dwarf::DW_OP_stack_value);<br>
+ AddOpStackValue();<br>
}<br>
<br>
static unsigned getOffsetOrZero(unsigned OffsetInBits,<br>
@@ -212,15 +215,30 @@ bool DwarfExpression::AddMachineRegExpre<br>
getOffsetOrZero(OffsetInBits, PieceOffsetInBits));<br>
}<br>
case dwarf::DW_OP_plus: {<br>
- // [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].<br>
auto N = I.getNext();<br>
+ unsigned Offset = I->getArg(0);<br>
+ // First combine all DW_OP_plus until we hit either a DW_OP_deref or a<br>
+ // DW_OP_bit_piece<br>
+ while (N != E && N->getOp() == dwarf::DW_OP_plus) {<br>
+ Offset += N->getArg(0);<br>
+ ++I;<br>
+ N = I.getNext();<br>
+ }<br>
if (N != E && N->getOp() == dwarf::DW_OP_deref) {<br>
- unsigned Offset = I->getArg(0);<br>
+ // [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].<br>
ValidReg = AddMachineRegIndirect(MachineReg, Offset);<br>
std::advance(I, 2);<br>
- break;<br>
- } else<br>
- ValidReg = AddMachineRegPiece(MachineReg);<br>
+ } else {<br>
+ assert ((N == E) || (N->getOp() == dwarf::DW_OP_bit_piece));<br>
+ if (Offset == 0) {<br>
+ ValidReg = AddMachineRegPiece(MachineReg);<br>
+ } else {<br>
+ ValidReg = AddMachineRegIndirect(MachineReg, Offset);<br>
+ AddOpStackValue();<br>
+ }<br>
+ ++I;<br>
+ }<br>
+ break;<br>
}<br>
case dwarf::DW_OP_deref: {<br>
// [DW_OP_reg,DW_OP_deref] --> [DW_OP_breg].<br>
@@ -237,6 +255,7 @@ bool DwarfExpression::AddMachineRegExpre<br>
<br>
// Emit remaining elements of the expression.<br>
AddExpression(I, E, PieceOffsetInBits);<br>
+<br>
return true;<br>
}<br>
<br>
<br>
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h<br>
URL: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_lib_CodeGen_AsmPrinter_DwarfExpression.h-3Frev-3D239380-26r1-3D239379-26r2-3D239380-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=mYgvIlV-j3fFDgrYiDAsPzDdMoLWRPYzOdSO9GI1ZFU&s=8RzaJNWVC9MSD__OLNwE9vfmyRy97EPdmDjYyVbTa6o&e=" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h?rev=239380&r1=239379&r2=239380&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h (original)<br>
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h Mon Jun 8 20:53:59 2015<br>
@@ -83,6 +83,9 @@ public:<br>
bool AddMachineRegPiece(unsigned MachineReg, unsigned PieceSizeInBits = 0,<br>
unsigned PieceOffsetInBits = 0);<br>
<br>
+ /// Emit a DW_OP_stack_value<br>
+ void AddOpStackValue();<br>
+<br>
/// Emit a signed constant.<br>
void AddSignedConstant(int Value);<br>
/// Emit an unsigned constant.<br>
<br>
Added: llvm/trunk/test/DebugInfo/expressions.ll<br>
URL: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_test_DebugInfo_expressions.ll-3Frev-3D239380-26view-3Dauto&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=mYgvIlV-j3fFDgrYiDAsPzDdMoLWRPYzOdSO9GI1ZFU&s=v48kNQsKou10zJWfRw_nRGBWyJc1jfM1oWtErtb6-0w&e=" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/expressions.ll?rev=239380&view=auto</a><br>
==============================================================================<br>
--- llvm/trunk/test/DebugInfo/expressions.ll (added)<br>
+++ llvm/trunk/test/DebugInfo/expressions.ll Mon Jun 8 20:53:59 2015<br>
@@ -0,0 +1,110 @@<br>
+; REQUIRES: object-emission<br>
+; RUN: %llc_dwarf -mtriple x86_64-apple-darwin14.0.0-elf -filetype=obj %s -o %t<br>
+; RUN: %llc_dwarf -mtriple x86_64-apple-darwin14.0.0-elf -O0 -filetype=obj %s -o %t0<br>
+; RUN: llvm-dwarfdump -debug-dump=loc %t | FileCheck %s<br>
+; RUN: llvm-dwarfdump -debug-dump=loc %t0 | FileCheck -check-prefix CHECK-O0 %s<br>
+<br>
+; CHECK: 0x00000000: Beginning address offset: 0x0000000000000000<br>
+; CHECK: Ending address offset: 0x[[END:[0-9a-f]+]]<br>
+; CHECK: Location description:<br>
+; CHECK-NOT: 75 00 55<br>
+; CHECK-SAME: 55<br>
+; CHECK: 0x00000023: Beginning address offset: 0x0000000000000000<br>
+; CHECK: Ending address offset: 0x{{.*}}[[END]]<br>
+; CHECK: Location description: 75 08 9f<br>
+; CHECK: 0x00000048: Beginning address offset: 0x0000000000000000<br>
+; CHECK: Ending address offset: 0x{{.*}}[[END]]<br>
+; CHECK: Location description: 75 10 9f<br>
+; CHECK: 0x0000006d: Beginning address offset: 0x0000000000000000<br>
+; CHECK: Ending address offset: 0x{{.*}}[[END]]<br>
+; CHECK: Location description: 75 18<br>
+<br>
+<br>
+; CHECK-O0: 0x00000000: Beginning address offset: 0x0000000000000000<br>
+; CHECK-O0: Ending address offset: 0x000000000000001b<br>
+; CHECK-O0: Location description: 55<br>
+; CHECK-O0: Beginning address offset: 0x000000000000001b<br>
+; CHECK-O0: Ending address offset: 0x0000000000000024<br>
+; CHECK-O0: Location description: 54<br>
+; CHECK-O0: Beginning address offset: 0x0000000000000024<br>
+; CHECK-O0: Ending address offset: 0x0000000000000025<br>
+; CHECK-O0: Location description: 77 78 23 00<br>
+; CHECK-O0: 0x0000004c: Beginning address offset: 0x0000000000000000<br>
+; CHECK-O0: Ending address offset: 0x000000000000001b<br>
+; CHECK-O0: Location description: 75 08 9f<br>
+; CHECK-O0: Beginning address offset: 0x000000000000001b<br>
+; CHECK-O0: Ending address offset: 0x0000000000000024<br>
+; CHECK-O0: Location description: 74 08 9f<br>
+; CHECK-O0: Beginning address offset: 0x0000000000000024<br>
+; CHECK-O0: Ending address offset: 0x0000000000000025<br>
+; CHECK-O0: Location description: 77 78 23 08<br>
+; CHECK-O0: 0x0000009c: Beginning address offset: 0x0000000000000000<br>
+; CHECK-O0: Ending address offset: 0x000000000000001b<br>
+; CHECK-O0: Location description: 75 10 9f<br>
+; CHECK-O0: Beginning address offset: 0x000000000000001b<br>
+; CHECK-O0: Ending address offset: 0x0000000000000024<br>
+; CHECK-O0: Location description: 74 10 9f<br>
+; CHECK-O0: Beginning address offset: 0x0000000000000024<br>
+; CHECK-O0: Ending address offset: 0x0000000000000025<br>
+; CHECK-O0: Location description: 77 78 23 08 23 08<br>
+; CHECK-O0: 0x000000ee: Beginning address offset: 0x0000000000000000<br>
+; CHECK-O0: Ending address offset: 0x000000000000001b<br>
+; CHECK-O0: Location description: 75 18<br>
+; CHECK-O0: Beginning address offset: 0x000000000000001b<br>
+; CHECK-O0: Ending address offset: 0x0000000000000024<br>
+; CHECK-O0: Location description: 74 18<br>
+; CHECK-O0: Beginning address offset: 0x0000000000000024<br>
+; CHECK-O0: Ending address offset: 0x0000000000000025<br>
+; CHECK-O0: Location description: 77 78 23 10 23 08 06<br>
+<br>
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #0<br>
+<br>
+define float @foo(float* %args, float *%args2)<br>
+{<br>
+ call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !11, metadata !12), !dbg !19<br>
+ call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !13, metadata !14), !dbg !19<br>
+ call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !15, metadata !16), !dbg !19<br>
+ call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !17, metadata !18), !dbg !19<br>
+ %a = load float, float* %args, !dbg !19<br>
+ %bptr = getelementptr float, float* %args, i32 1, !dbg !19<br>
+ %b = load float, float* %bptr, !dbg !19<br>
+ %cptr = getelementptr float, float* %args, i32 2, !dbg !19<br>
+ %c = load float, float* %cptr, !dbg !19<br>
+ %dptr = getelementptr float, float* %args, i32 3, !dbg !19<br>
+ %d = load float, float* %dptr, !dbg !19<br>
+ %ret1 = fadd float %a, %b, !dbg !19<br>
+ %ret2 = fadd float %c, %d, !dbg !19<br>
+ call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !11, metadata !12), !dbg !19<br>
+ call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !13, metadata !14), !dbg !19<br>
+ call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !15, metadata !16), !dbg !19<br>
+ call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !17, metadata !18), !dbg !19<br>
+ %ret = fsub float %ret1, %ret2, !dbg !19<br>
+ ret float %ret, !dbg !19<br>
+}<br>
+<br>
+attributes #0 = { nounwind readnone }<br>
+<br>
+!llvm.module.flags = !{!0, !1}<br>
+!<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.dbg.cu&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=mYgvIlV-j3fFDgrYiDAsPzDdMoLWRPYzOdSO9GI1ZFU&s=lIzV-D1biw3Mzp4QCqigi5wdGXUI6LM2D9QAii8YhUs&e=" target="_blank">llvm.dbg.cu</a> = !{!2}<br>
+<br>
+!0 = !{i32 2, !"Dwarf Version", i32 4}<br>
+!1 = !{i32 1, !"Debug Info Version", i32 3}<br>
+<br>
+!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)<br>
+!3 = !DIFile(filename: "expressions", directory: ".")<br>
+!4 = !{}<br>
+!5 = !{!6}<br>
+!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)<br>
+!7 = !DISubroutineType(types: !8)<br>
+!8 = !{!10, !10}<br>
+!9 = !DIBasicType(name: "float", size: 4, align: 4, encoding: DW_ATE_float)<br>
+!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64, align: 64)<br>
+!11 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "a", arg: 1, scope: !6, file: !3, line: 1, type: !10)<br>
+!12 = !DIExpression(DW_OP_plus, 0)<br>
+!13 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "b", arg: 2, scope: !6, file: !3, line: 1, type: !10)<br>
+!14 = !DIExpression(DW_OP_plus, 8)<br>
+!15 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "c", arg: 3, scope: !6, file: !3, line: 1, type: !10)<br>
+!16 = !DIExpression(DW_OP_plus, 8, DW_OP_plus, 8)<br>
+!17 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "d", arg: 4, scope: !6, file: !3, line: 1, type: !9)<br>
+!18 = !DIExpression(DW_OP_plus, 16, DW_OP_plus, 8, DW_OP_deref)<br>
+!19 = !DILocation(line: 1, scope: !6)<br>
<br>
<br>
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</blockquote></div><br></div>