ffc498dfcc
Summary: This patch is part of 3 patches that together form a single patch, but must be introduced in stages in order not to break things. The way that LLVM interprets DW_OP_plus in DIExpression nodes is basically that of the DW_OP_plus_uconst operator since LLVM expects an unsigned constant operand. This unnecessarily restricts the DW_OP_plus operator, preventing it from being used to describe the evaluation of runtime values on the expression stack. These patches try to align the semantics of DW_OP_plus and DW_OP_minus with that of the DWARF definition, which pops two elements off the expression stack, performs the operation and pushes the result back on the stack. This is done in three stages: • The first patch (LLVM) adds support for DW_OP_plus_uconst. • The second patch (Clang) contains changes all its uses from DW_OP_plus to DW_OP_plus_uconst. • The third patch (LLVM) changes the semantics of DW_OP_plus and DW_OP_minus to be in line with its DWARF meaning. This patch includes the bitcode upgrade from legacy DIExpressions. Patch by Sander de Smalen. Reviewers: echristo, pcc, aprantl Reviewed By: aprantl Subscribers: fhahn, javed.absar, aprantl, llvm-commits Differential Revision: https://reviews.llvm.org/D33894 llvm-svn: 305386
99 lines
4.9 KiB
LLVM
99 lines
4.9 KiB
LLVM
; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
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; Test llvm.dbg.value for the local variables moved onto the unsafe stack.
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; SafeStack rewrites them relative to the unsafe stack pointer (base address of
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; the unsafe stack frame).
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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; Function Attrs: noinline safestack uwtable
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define void @f() #0 !dbg !6 {
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entry:
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; CHECK: %[[USP:.*]] = load i8*, i8** @__safestack_unsafe_stack_ptr
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%x1 = alloca i32, align 4
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%x2 = alloca i32, align 4
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%0 = bitcast i32* %x1 to i8*, !dbg !13
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%1 = bitcast i32* %x2 to i8*, !dbg !14
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; Unhandled dbg.value: expression does not start with OP_DW_deref
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; CHECK: call void @llvm.dbg.value(metadata ![[EMPTY:.*]], i64 0, metadata !{{.*}}, metadata !{{.*}})
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tail call void @llvm.dbg.value(metadata i32* %x1, i64 0, metadata !10, metadata !23), !dbg !16
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; Unhandled dbg.value: expression does not start with OP_DW_deref
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; CHECK: call void @llvm.dbg.value(metadata ![[EMPTY]], i64 0, metadata !{{.*}}, metadata !{{.*}})
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tail call void @llvm.dbg.value(metadata i32* %x1, i64 0, metadata !10, metadata !24), !dbg !16
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; Supported dbg.value: rewritted based on the [[USP]] value.
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; CHECK: call void @llvm.dbg.value(metadata i8* %[[USP]], i64 0, metadata ![[X1:.*]], metadata ![[X1_EXPR:.*]])
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tail call void @llvm.dbg.value(metadata i32* %x1, i64 0, metadata !10, metadata !15), !dbg !16
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call void @capture(i32* nonnull %x1), !dbg !17
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; An extra non-dbg.value metadata use of %x2. Replaced with an empty metadata.
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; CHECK: call void @llvm.random.metadata.use(metadata ![[EMPTY]])
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call void @llvm.random.metadata.use(metadata i32* %x2)
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; CHECK: call void @llvm.dbg.value(metadata i8* %[[USP]], i64 0, metadata ![[X2:.*]], metadata ![[X2_EXPR:.*]])
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call void @llvm.dbg.value(metadata i32* %x2, i64 0, metadata !12, metadata !15), !dbg !18
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call void @capture(i32* nonnull %x2), !dbg !19
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ret void, !dbg !20
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}
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; Function Attrs: argmemonly nounwind
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declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #1
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declare void @capture(i32*) #2
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; Function Attrs: argmemonly nounwind
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declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
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; Function Attrs: nounwind readnone
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declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #3
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declare void @llvm.random.metadata.use(metadata)
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attributes #0 = { noinline safestack uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #1 = { argmemonly nounwind }
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attributes #2 = { "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"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #3 = { nounwind readnone }
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attributes #4 = { nounwind }
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4}
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!llvm.ident = !{!5}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 271022) (llvm/trunk 271027)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
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!1 = !DIFile(filename: "../llvm/2.cc", directory: "/code/build-llvm")
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; CHECK-DAG: ![[EMPTY]] = !{}
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!2 = !{}
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{!"clang version 3.9.0 (trunk 271022) (llvm/trunk 271027)"}
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!6 = distinct !DISubprogram(name: "f", linkageName: "_Z1fv", scope: !1, file: !1, line: 4, type: !7, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !9)
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!7 = !DISubroutineType(types: !8)
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!8 = !{null}
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!9 = !{!10, !12}
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; CHECK-DAG: ![[X1]] = !DILocalVariable(name: "x1",
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!10 = !DILocalVariable(name: "x1", scope: !6, file: !1, line: 5, type: !11)
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!11 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
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; CHECK-DAG: ![[X2]] = !DILocalVariable(name: "x2",
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!12 = !DILocalVariable(name: "x2", scope: !6, file: !1, line: 6, type: !11)
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!13 = !DILocation(line: 5, column: 3, scope: !6)
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!14 = !DILocation(line: 6, column: 3, scope: !6)
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; CHECK-DAG: ![[X1_EXPR]] = !DIExpression(DW_OP_deref, DW_OP_constu, 4, DW_OP_minus)
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; CHECK-DAG: ![[X2_EXPR]] = !DIExpression(DW_OP_deref, DW_OP_constu, 8, DW_OP_minus)
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!15 = !DIExpression(DW_OP_deref)
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!16 = !DILocation(line: 5, column: 7, scope: !6)
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!17 = !DILocation(line: 8, column: 3, scope: !6)
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!18 = !DILocation(line: 6, column: 7, scope: !6)
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!19 = !DILocation(line: 9, column: 3, scope: !6)
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!20 = !DILocation(line: 10, column: 1, scope: !6)
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!21 = !DILocation(line: 10, column: 1, scope: !22)
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!22 = !DILexicalBlockFile(scope: !6, file: !1, discriminator: 1)
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!23 = !DIExpression()
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!24 = !DIExpression(DW_OP_constu, 42, DW_OP_minus)
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