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Fix debug info with SafeStack. 

llvm-svn: 248933
This commit is contained in:
Evgeniy Stepanov 2015-09-30 19:55:43 +00:00
parent 57737529fe
commit f608111d1b
8 changed files with 198 additions and 17 deletions
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7
llvm/include/llvm/Transforms/Utils/Local.h
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@ -272,10 +272,11 @@ bool LowerDbgDeclare(Function &F);
DbgDeclareInst *FindAllocaDbgDeclare(Value *V);
/// \brief Replaces llvm.dbg.declare instruction when an alloca is replaced with
/// a new value. If Deref is true, tan additional DW_OP_deref is prepended to
/// the expression.
/// a new value. If Deref is true, an additional DW_OP_deref is prepended to the
/// expression. If Offset is non-zero, a constant displacement is added to the
/// expression (after the optional Deref). Offset can be negative.
bool replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
DIBuilder &Builder, bool Deref);
DIBuilder &Builder, bool Deref, int Offset = 0);
/// Replace 'BB's terminator with one that does not have an unwind successor
/// block. Rewrites `invoke` to `call`, `catchendpad unwind label %foo` to

15
llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
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@ -211,12 +211,15 @@ bool DwarfExpression::AddMachineRegExpression(const DIExpression *Expr,
return AddMachineRegPiece(MachineReg, SizeInBits,
getOffsetOrZero(OffsetInBits, PieceOffsetInBits));
}
case dwarf::DW_OP_plus: {
// [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].
case dwarf::DW_OP_plus:
case dwarf::DW_OP_minus: {
// [DW_OP_reg,Offset,DW_OP_plus, DW_OP_deref] --> [DW_OP_breg, Offset].
// [DW_OP_reg,Offset,DW_OP_minus,DW_OP_deref] --> [DW_OP_breg,-Offset].
auto N = I.getNext();
if (N != E && N->getOp() == dwarf::DW_OP_deref) {
unsigned Offset = I->getArg(0);
ValidReg = AddMachineRegIndirect(MachineReg, Offset);
ValidReg = AddMachineRegIndirect(
MachineReg, I->getOp() == dwarf::DW_OP_plus ? Offset : -Offset);
std::advance(I, 2);
break;
} else
@ -255,6 +258,12 @@ void DwarfExpression::AddExpression(DIExpression::expr_op_iterator I,
EmitOp(dwarf::DW_OP_plus_uconst);
EmitUnsigned(I->getArg(0));
break;
case dwarf::DW_OP_minus:
// There is no OP_minus_uconst.
EmitOp(dwarf::DW_OP_constu);
EmitUnsigned(I->getArg(0));
EmitOp(dwarf::DW_OP_minus);
break;
case dwarf::DW_OP_deref:
EmitOp(dwarf::DW_OP_deref);
break;

8
llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
View File

@ -4394,15 +4394,9 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
N);
return nullptr;
}
} else if (AI)
} else {
SDV = DAG.getDbgValue(Variable, Expression, N.getNode(), N.getResNo(),
true, 0, dl, SDNodeOrder);
else {
// Can't do anything with other non-AI cases yet.
DEBUG(dbgs() << "Dropping debug info for " << DI << "\n");
DEBUG(dbgs() << "non-AllocaInst issue for Address: \n\t");
DEBUG(Address->dump());
return nullptr;
}
DAG.AddDbgValue(SDV, N.getNode(), isParameter);
} else {

2
llvm/lib/IR/DebugInfoMetadata.cpp
View File

@ -496,6 +496,7 @@ unsigned DIExpression::ExprOperand::getSize() const {
case dwarf::DW_OP_bit_piece:
return 3;
case dwarf::DW_OP_plus:
case dwarf::DW_OP_minus:
return 2;
default:
return 1;
@ -516,6 +517,7 @@ bool DIExpression::isValid() const {
// Piece expressions must be at the end.
return I->get() + I->getSize() == E->get();
case dwarf::DW_OP_plus:
case dwarf::DW_OP_minus:
case dwarf::DW_OP_deref:
break;
}

2
llvm/lib/Transforms/Instrumentation/SafeStack.cpp
View File

@ -443,7 +443,7 @@ SafeStack::moveStaticAllocasToUnsafeStack(IRBuilder<> &IRB, Function &F,
cast<Instruction>(NewAI)->takeName(AI);
// Replace alloc with the new location.
replaceDbgDeclareForAlloca(AI, NewAI, DIB, /*Deref=*/true);
replaceDbgDeclareForAlloca(AI, BasePointer, DIB, /*Deref=*/true, -StaticOffset);
AI->replaceAllUsesWith(NewAI);
AI->eraseFromParent();
}

14
llvm/lib/Transforms/Utils/Local.cpp
View File

@ -1136,7 +1136,7 @@ DbgDeclareInst *llvm::FindAllocaDbgDeclare(Value *V) {
}
bool llvm::replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
DIBuilder &Builder, bool Deref) {
DIBuilder &Builder, bool Deref, int Offset) {
DbgDeclareInst *DDI = FindAllocaDbgDeclare(AI);
if (!DDI)
return false;
@ -1145,13 +1145,21 @@ bool llvm::replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
auto *DIExpr = DDI->getExpression();
assert(DIVar && "Missing variable");
if (Deref) {
if (Deref || Offset) {
// Create a copy of the original DIDescriptor for user variable, prepending
// "deref" operation to a list of address elements, as new llvm.dbg.declare
// will take a value storing address of the memory for variable, not
// alloca itself.
SmallVector<uint64_t, 4> NewDIExpr;
NewDIExpr.push_back(dwarf::DW_OP_deref);
if (Deref)
NewDIExpr.push_back(dwarf::DW_OP_deref);
if (Offset > 0) {
NewDIExpr.push_back(dwarf::DW_OP_plus);
NewDIExpr.push_back(Offset);
} else if (Offset < 0) {
NewDIExpr.push_back(dwarf::DW_OP_minus);
NewDIExpr.push_back(-Offset);
}
if (DIExpr)
NewDIExpr.append(DIExpr->elements_begin(), DIExpr->elements_end());
DIExpr = Builder.createExpression(NewDIExpr);

84
llvm/test/DebugInfo/Generic/dw_op_minus.ll Normal file
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@ -0,0 +1,84 @@
; Test dwarf codegen of DW_OP_minus.
; RUN: llc -O0 -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck %s
; This was built by compiling the following source with SafeStack and
; simplifying the result a little.
; extern "C" {
; void Capture(int *);
; void f() {
; int buf[100];
; Capture(buf);
; }
; }
; The interesting part is !DIExpression(DW_OP_deref, DW_OP_minus, 400)
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@__safestack_unsafe_stack_ptr = external thread_local(initialexec) global i8*
define void @f() {
entry:
%unsafe_stack_ptr = load i8*, i8** @__safestack_unsafe_stack_ptr
%unsafe_stack_static_top = getelementptr i8, i8* %unsafe_stack_ptr, i32 -400
store i8* %unsafe_stack_static_top, i8** @__safestack_unsafe_stack_ptr
%0 = getelementptr i8, i8* %unsafe_stack_ptr, i32 -400
%buf = bitcast i8* %0 to [100 x i32]*
%1 = bitcast [100 x i32]* %buf to i8*, !dbg !16
call void @llvm.dbg.declare(metadata i8* %unsafe_stack_ptr, metadata !8, metadata !17), !dbg !18
%arraydecay = getelementptr inbounds [100 x i32], [100 x i32]* %buf, i64 0, i64 0, !dbg !19
call void @Capture(i32* %arraydecay), !dbg !20
store i8* %unsafe_stack_ptr, i8** @__safestack_unsafe_stack_ptr, !dbg !21
ret void, !dbg !21
}
; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata, metadata) nounwind readnone
declare void @Capture(i32*)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!13, !14}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 248518) (llvm/trunk 248512)", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
!1 = !DIFile(filename: "1.cc", directory: "/tmp")
!2 = !{}
!3 = !{!4}
!4 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 4, type: !5, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: true, function: void ()* @f, variables: !7)
!5 = !DISubroutineType(types: !6)
!6 = !{null}
!7 = !{!8}
!8 = !DILocalVariable(name: "buf", scope: !4, file: !1, line: 5, type: !9)
!9 = !DICompositeType(tag: DW_TAG_array_type, baseType: !10, size: 3200, align: 32, elements: !11)
!10 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!11 = !{!12}
!12 = !DISubrange(count: 100)
!13 = !{i32 2, !"Dwarf Version", i32 4}
!14 = !{i32 2, !"Debug Info Version", i32 3}
!15 = !{!"clang version 3.8.0 (trunk 248518) (llvm/trunk 248512)"}
!16 = !DILocation(line: 5, column: 3, scope: !4)
!17 = !DIExpression(DW_OP_deref, DW_OP_minus, 400)
!18 = !DILocation(line: 5, column: 7, scope: !4)
!19 = !DILocation(line: 6, column: 11, scope: !4)
!20 = !DILocation(line: 6, column: 3, scope: !4)
!21 = !DILocation(line: 7, column: 1, scope: !4)
; RCX - 400
; CHECK: .short 6 # Loc expr size
; CHECK-NEXT: .byte 114 # DW_OP_breg2
; CHECK-NEXT: .byte 0 # 0
; CHECK-NEXT: .byte 16 # DW_OP_constu
; CHECK-NEXT: .byte 144 # 400
; CHECK-NEXT: .byte 3 # DW_OP_minus
; CHECK-NEXT: .byte 28
; RCX is clobbered in call @Capture, but there is a spilled copy.
; *(RSP + 8) - 400
; CHECK: .short 7 # Loc expr size
; CHECK-NEXT: .byte 119 # DW_OP_breg7
; CHECK-NEXT: .byte 8 # 8
; CHECK-NEXT: .byte 6 # DW_OP_deref
; CHECK-NEXT: .byte 16 # DW_OP_constu
; CHECK-NEXT: .byte 144 # 400
; CHECK-NEXT: .byte 3 # DW_OP_minus
; CHECK-NEXT: .byte 28

83
llvm/test/Transforms/SafeStack/debug-loc.ll Normal file
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@ -0,0 +1,83 @@
; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
; Test debug location for the local variables moved onto the unsafe stack.
; CHECK: define void @f
; CHECK: %[[USP:.*]] = load i8*, i8** @__safestack_unsafe_stack_ptr
; dbg.declare for %buf is gone; replaced with dbg.declare based off the unsafe stack pointer
; CHECK-NOT: @llvm.dbg.declare.*%buf
; CHECK: call void @llvm.dbg.declare(metadata i8* %[[USP]], metadata ![[VAR:.*]], metadata ![[EXPR:.*]])
; dbg.declare appears before the first use of %buf
; CHECK: getelementptr{{.*}}%buf
; CHECK: call{{.*}}@Capture
; CHECK: ret void
; dbg.declare describes "buf"...
; CHECK: ![[VAR]] = !DILocalVariable(name: "buf"
; ... as an offset from the unsafe stack pointer
; CHECK: ![[EXPR]] = !DIExpression(DW_OP_deref, DW_OP_minus, 400)
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: safestack uwtable
define void @f() #0 {
entry:
%buf = alloca [100 x i32], align 16
%0 = bitcast [100 x i32]* %buf to i8*, !dbg !16
call void @llvm.lifetime.start(i64 400, i8* %0) #4, !dbg !16
tail call void @llvm.dbg.declare(metadata [100 x i32]* %buf, metadata !8, metadata !17), !dbg !18
%arraydecay = getelementptr inbounds [100 x i32], [100 x i32]* %buf, i64 0, i64 0, !dbg !19
call void @Capture(i32* %arraydecay), !dbg !20
call void @llvm.lifetime.end(i64 400, i8* %0) #4, !dbg !21
ret void, !dbg !21
}
; Function Attrs: nounwind argmemonly
declare void @llvm.lifetime.start(i64, i8* nocapture) #1
; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata, metadata) #2
declare void @Capture(i32*) #3
; Function Attrs: nounwind argmemonly
declare void @llvm.lifetime.end(i64, i8* nocapture) #1
attributes #0 = { safestack uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { nounwind argmemonly }
attributes #2 = { nounwind readnone }
attributes #3 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #4 = { nounwind }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!13, !14}
!llvm.ident = !{!15}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 248518) (llvm/trunk 248512)", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
!1 = !DIFile(filename: "1.cc", directory: "/tmp")
!2 = !{}
!3 = !{!4}
!4 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 4, type: !5, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: true, function: void ()* @f, variables: !7)
!5 = !DISubroutineType(types: !6)
!6 = !{null}
!7 = !{!8}
!8 = !DILocalVariable(name: "buf", scope: !4, file: !1, line: 5, type: !9)
!9 = !DICompositeType(tag: DW_TAG_array_type, baseType: !10, size: 3200, align: 32, elements: !11)
!10 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!11 = !{!12}
!12 = !DISubrange(count: 100)
!13 = !{i32 2, !"Dwarf Version", i32 4}
!14 = !{i32 2, !"Debug Info Version", i32 3}
!15 = !{!"clang version 3.8.0 (trunk 248518) (llvm/trunk 248512)"}
!16 = !DILocation(line: 5, column: 3, scope: !4)
!17 = !DIExpression()
!18 = !DILocation(line: 5, column: 7, scope: !4)
!19 = !DILocation(line: 6, column: 11, scope: !4)
!20 = !DILocation(line: 6, column: 3, scope: !4)
!21 = !DILocation(line: 7, column: 1, scope: !4)