llvm-6502/test/DebugInfo/X86/debug-loc-asan.ll

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Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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; RUN: llc -O0 -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck %s
; Verify that we have correct debug info for local variables in code
; instrumented with AddressSanitizer.
; Generated from the source file test.cc:
; int bar(int y) {
; return y + 2;
; }
; with "clang++ -S -emit-llvm -fsanitize=address -O0 -g test.cc"
; First, argument variable "y" resides in %rdi:
; CHECK: DEBUG_VALUE: bar:y <- RDI
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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; Then its address is stored in a location on a stack:
; CHECK: movq %rdi, [[OFFSET:[0-9]+]](%rsp)
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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; CHECK-NEXT: [[START_LABEL:.Ltmp[0-9]+]]
; CHECK-NEXT: DEBUG_VALUE: bar:y <- [RSP+[[OFFSET]]]
; This location should be valid until the end of the function.
; CHECK: .Ldebug_loc{{[0-9]+}}:
; We expect two location ranges for the variable.
; First, it is stored in %rdx:
; CHECK: .quad .Lfunc_begin0-.Lfunc_begin0
; CHECK-NEXT: .quad [[START_LABEL]]-.Lfunc_begin0
; CHECK: DW_OP_reg5
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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; Then it's addressed via %rsp:
; CHECK: .quad [[START_LABEL]]-.Lfunc_begin0
; CHECK-NEXT: .Lfunc_end0-.Lfunc_begin0
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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; CHECK: DW_OP_breg7
; CHECK-NEXT: [[OFFSET]]
; CHECK: DW_OP_deref
; ModuleID = 'test.cc'
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32, void ()* } { i32 1, void ()* @asan.module_ctor }]
@__asan_option_detect_stack_use_after_return = external global i32
@__asan_gen_ = private unnamed_addr constant [16 x i8] c"1 32 4 6 y.addr\00", align 1
; Function Attrs: nounwind sanitize_address uwtable
define i32 @_Z3bari(i32 %y) #0 {
entry:
%MyAlloca = alloca [64 x i8], align 32
%0 = ptrtoint [64 x i8]* %MyAlloca to i64
%1 = load i32* @__asan_option_detect_stack_use_after_return
%2 = icmp ne i32 %1, 0
br i1 %2, label %3, label %5
; <label>:3 ; preds = %entry
%4 = call i64 @__asan_stack_malloc_0(i64 64, i64 %0)
br label %5
; <label>:5 ; preds = %entry, %3
%6 = phi i64 [ %0, %entry ], [ %4, %3 ]
%7 = add i64 %6, 32
%8 = inttoptr i64 %7 to i32*
%9 = inttoptr i64 %6 to i64*
store i64 1102416563, i64* %9
%10 = add i64 %6, 8
%11 = inttoptr i64 %10 to i64*
store i64 ptrtoint ([16 x i8]* @__asan_gen_ to i64), i64* %11
%12 = add i64 %6, 16
%13 = inttoptr i64 %12 to i64*
store i64 ptrtoint (i32 (i32)* @_Z3bari to i64), i64* %13
%14 = lshr i64 %6, 3
%15 = add i64 %14, 2147450880
%16 = add i64 %15, 0
%17 = inttoptr i64 %16 to i64*
store i64 -868083100587789839, i64* %17
%18 = ptrtoint i32* %8 to i64
%19 = lshr i64 %18, 3
%20 = add i64 %19, 2147450880
%21 = inttoptr i64 %20 to i8*
%22 = load i8* %21
%23 = icmp ne i8 %22, 0
Move the complex address expression out of DIVariable and into an extra argument of the llvm.dbg.declare/llvm.dbg.value intrinsics. Previously, DIVariable was a variable-length field that has an optional reference to a Metadata array consisting of a variable number of complex address expressions. In the case of OpPiece expressions this is wasting a lot of storage in IR, because when an aggregate type is, e.g., SROA'd into all of its n individual members, the IR will contain n copies of the DIVariable, all alike, only differing in the complex address reference at the end. By making the complex address into an extra argument of the dbg.value/dbg.declare intrinsics, all of the pieces can reference the same variable and the complex address expressions can be uniqued across the CU, too. Down the road, this will allow us to move other flags, such as "indirection" out of the DIVariable, too. The new intrinsics look like this: declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr) declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr) This patch adds a new LLVM-local tag to DIExpressions, so we can detect and pretty-print DIExpression metadata nodes. What this patch doesn't do: This patch does not touch the "Indirect" field in DIVariable; but moving that into the expression would be a natural next step. http://reviews.llvm.org/D4919 rdar://problem/17994491 Thanks to dblaikie and dexonsmith for reviewing this patch! Note: I accidentally committed a bogus older version of this patch previously. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218787 91177308-0d34-0410-b5e6-96231b3b80d8
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call void @llvm.dbg.declare(metadata !{i32* %8}, metadata !12, metadata !14)
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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br i1 %23, label %24, label %30
; <label>:24 ; preds = %5
%25 = and i64 %18, 7
%26 = add i64 %25, 3
%27 = trunc i64 %26 to i8
%28 = icmp sge i8 %27, %22
br i1 %28, label %29, label %30
; <label>:29 ; preds = %24
call void @__asan_report_store4(i64 %18)
call void asm sideeffect "", ""()
unreachable
; <label>:30 ; preds = %24, %5
store i32 %y, i32* %8, align 4
%31 = ptrtoint i32* %8 to i64, !dbg !13
%32 = lshr i64 %31, 3, !dbg !13
%33 = add i64 %32, 2147450880, !dbg !13
%34 = inttoptr i64 %33 to i8*, !dbg !13
%35 = load i8* %34, !dbg !13
%36 = icmp ne i8 %35, 0, !dbg !13
br i1 %36, label %37, label %43, !dbg !13
; <label>:37 ; preds = %30
%38 = and i64 %31, 7, !dbg !13
%39 = add i64 %38, 3, !dbg !13
%40 = trunc i64 %39 to i8, !dbg !13
%41 = icmp sge i8 %40, %35, !dbg !13
br i1 %41, label %42, label %43
; <label>:42 ; preds = %37
call void @__asan_report_load4(i64 %31), !dbg !13
call void asm sideeffect "", ""()
unreachable
; <label>:43 ; preds = %37, %30
%44 = load i32* %8, align 4, !dbg !13
%add = add nsw i32 %44, 2, !dbg !13
store i64 1172321806, i64* %9, !dbg !13
%45 = icmp ne i64 %6, %0, !dbg !13
br i1 %45, label %46, label %53, !dbg !13
; <label>:46 ; preds = %43
%47 = add i64 %15, 0, !dbg !13
%48 = inttoptr i64 %47 to i64*, !dbg !13
store i64 -723401728380766731, i64* %48, !dbg !13
%49 = add i64 %6, 56, !dbg !13
%50 = inttoptr i64 %49 to i64*, !dbg !13
%51 = load i64* %50, !dbg !13
%52 = inttoptr i64 %51 to i8*, !dbg !13
store i8 0, i8* %52, !dbg !13
br label %56, !dbg !13
; <label>:53 ; preds = %43
%54 = add i64 %15, 0, !dbg !13
%55 = inttoptr i64 %54 to i64*, !dbg !13
store i64 0, i64* %55, !dbg !13
br label %56, !dbg !13
; <label>:56 ; preds = %53, %46
ret i32 %add, !dbg !13
}
; Function Attrs: nounwind readnone
Move the complex address expression out of DIVariable and into an extra argument of the llvm.dbg.declare/llvm.dbg.value intrinsics. Previously, DIVariable was a variable-length field that has an optional reference to a Metadata array consisting of a variable number of complex address expressions. In the case of OpPiece expressions this is wasting a lot of storage in IR, because when an aggregate type is, e.g., SROA'd into all of its n individual members, the IR will contain n copies of the DIVariable, all alike, only differing in the complex address reference at the end. By making the complex address into an extra argument of the dbg.value/dbg.declare intrinsics, all of the pieces can reference the same variable and the complex address expressions can be uniqued across the CU, too. Down the road, this will allow us to move other flags, such as "indirection" out of the DIVariable, too. The new intrinsics look like this: declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr) declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr) This patch adds a new LLVM-local tag to DIExpressions, so we can detect and pretty-print DIExpression metadata nodes. What this patch doesn't do: This patch does not touch the "Indirect" field in DIVariable; but moving that into the expression would be a natural next step. http://reviews.llvm.org/D4919 rdar://problem/17994491 Thanks to dblaikie and dexonsmith for reviewing this patch! Note: I accidentally committed a bogus older version of this patch previously. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218787 91177308-0d34-0410-b5e6-96231b3b80d8
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declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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define internal void @asan.module_ctor() {
call void @__asan_init_v3()
ret void
}
declare void @__asan_init_v3()
declare void @__asan_report_load4(i64)
declare void @__asan_report_store4(i64)
declare i64 @__asan_stack_malloc_0(i64, i64)
attributes #0 = { nounwind sanitize_address uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { nounwind readnone }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!9, !10}
!llvm.ident = !{!11}
!0 = metadata !{metadata !"0x11\004\00clang version 3.5.0 (209308)\000\00\000\00\001", metadata !1, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2} ; [ DW_TAG_compile_unit ] [/llvm_cmake_gcc/test.cc] [DW_LANG_C_plus_plus]
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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!1 = metadata !{metadata !"test.cc", metadata !"/llvm_cmake_gcc"}
!2 = metadata !{}
!3 = metadata !{metadata !4}
!4 = metadata !{metadata !"0x2e\00bar\00bar\00_Z3bari\001\000\001\000\006\00256\000\001", metadata !1, metadata !5, metadata !6, null, i32 (i32)* @_Z3bari, null, null, metadata !2} ; [ DW_TAG_subprogram ] [line 1] [def] [bar]
!5 = metadata !{metadata !"0x29", metadata !1} ; [ DW_TAG_file_type ] [/llvm_cmake_gcc/test.cc]
!6 = metadata !{metadata !"0x15\00\000\000\000\000\000\000", i32 0, null, null, metadata !7, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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!7 = metadata !{metadata !8, metadata !8}
!8 = metadata !{metadata !"0x24\00int\000\0032\0032\000\000\005", null, null} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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!9 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
!10 = metadata !{i32 2, metadata !"Debug Info Version", i32 2}
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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!11 = metadata !{metadata !"clang version 3.5.0 (209308)"}
!12 = metadata !{metadata !"0x101\00y\0016777217\000", metadata !4, metadata !5, metadata !8} ; [ DW_TAG_arg_variable ] [y] [line 1]
Generate better location ranges for some register-described variables. Don't terminate location ranges for register-described variables at the end of machine basic block if this register is never modified in the function body, except for the prologue and epilogue. Prologue location is guessed by FrameSetup flags on MachineInstructions, while epilogue location is deduced from debug locations of instructions in the basic blocks ending with return instructions. This patch is mostly targeted to fix non-trivial debug locations for variables addressed via stack and frame pointers. It is not really a generic fix. We can still produce poor debug info for register-described variables if this register *is* modified somewhere in the function, but in unrelated places. This might be the case for the debug info in optimized binaries (e.g. for local variables in inlined functions). LiveDebugVariables pass in CodeGen attempts to fix this problem by adjusting DBG_VALUE instructions, but this pass is tied to greedy register allocator, which is used in optimized builds only. Proper fix would likely involve generalizing LiveDebugVariables to all register allocators. See more discussion in http://reviews.llvm.org/D3933 review thread. I'm proceeding with this patch to fix immediate severe problems and important cases, e.g. fix completely broken debug info with AddressSanitizer and fix PR19307 (missing debug info for by-value std::string arguments). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210492 91177308-0d34-0410-b5e6-96231b3b80d8
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!13 = metadata !{i32 2, i32 0, metadata !4, null}
!14 = metadata !{metadata !"0x102\006"} ; [ DW_TAG_expression ] [DW_OP_deref]