[llvm] r223799 - Correctly handle complex locations expressions in replaceDbgDeclareForAlloca()
Alexey Samsonov
vonosmas at gmail.com
Tue Dec 9 12:02:45 PST 2014
Thanks for the fix!
On Tue, Dec 9, 2014 at 10:27 AM, Frédéric Riss <friss at apple.com> wrote:
>
> On Dec 9, 2014, at 10:11 AM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
>
> On Tue, Dec 9, 2014 at 9:55 AM, Frederic Riss <friss at apple.com> wrote:
>
>> Author: friss
>> Date: Tue Dec 9 11:55:48 2014
>> New Revision: 223799
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=223799&view=rev
>> Log:
>> Correctly handle complex locations expressions in
>> replaceDbgDeclareForAlloca()
>>
>> replaceDbgDeclareForAlloca() replaces an alloca by a value storing the
>> address of what was the alloca. If there is a dbg.declare corresponding
>> to that alloca, we need to lower it to a dbg.value describing the
>> additional
>> dereference operation to be performed to get to the underlying variable.
>> This is done by adding a DW_OP_deref to the complex location part of the
>> location description. This deref was added to the end of the operation
>> list,
>> which is wrong. The expression applies to what is described by the
>> dbg.{declare,value}, and as we are changing this, we need to apply the
>> DW_OP_deref as the first operation in the list.
>>
>> Part of the fix for rdar://19162268.
>>
>> Added:
>> llvm/trunk/test/DebugInfo/block-asan.ll
>> Modified:
>> llvm/trunk/lib/Transforms/Utils/Local.cpp
>>
>> Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=223799&r1=223798&r2=223799&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
>> +++ llvm/trunk/lib/Transforms/Utils/Local.cpp Tue Dec 9 11:55:48 2014
>> @@ -1111,7 +1111,7 @@ bool llvm::replaceDbgDeclareForAlloca(Al
>> if (!DIVar)
>> return false;
>>
>> - // Create a copy of the original DIDescriptor for user variable,
>> appending
>> + // 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.
>> @@ -1121,7 +1121,7 @@ bool llvm::replaceDbgDeclareForAlloca(Al
>> NewDIExpr.push_back(DIExpr.getElement(i));
>> }
>> }
>> - NewDIExpr.push_back(dwarf::DW_OP_deref);
>> + NewDIExpr.insert(NewDIExpr.begin(), dwarf::DW_OP_deref);
>>
>
> Could we move this to before the loop, so we don't have to shift
> everything up in the vector to make space for this new first element?
>
>
> Sure, I didn’t even notice that we copied the expression, I thought we
> were just reusing the one we replace! Thanks for the catch.
> I’ll retest before committing, but this will go in shortly.
>
> Fred
>
>
>> // Insert llvm.dbg.declare in the same basic block as the original
>> alloca,
>> // and remove old llvm.dbg.declare.
>>
>> Added: llvm/trunk/test/DebugInfo/block-asan.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/block-asan.ll?rev=223799&view=auto
>>
>> ==============================================================================
>> --- llvm/trunk/test/DebugInfo/block-asan.ll (added)
>> +++ llvm/trunk/test/DebugInfo/block-asan.ll Tue Dec 9 11:55:48 2014
>> @@ -0,0 +1,87 @@
>> +; RUN: opt -S -asan %s | FileCheck %s
>> +
>> +; The IR of this testcase is generated from the following C code:
>> +; void bar (int);
>> +;
>> +; void foo() {
>> +; __block int x;
>> +; bar(x);
>> +; }
>> +; by compiling it with 'clang -emit-llvm -g -S' and then by manually
>> +; adding the sanitize_address attribute to the @foo() function (so
>> +; that ASAN accepts to instrument the function in the above opt run).
>> +
>> +; Check that the location of the ASAN instrumented __block variable is
>> +; correct.
>> +; CHECK: [ DW_TAG_expression ] [DW_OP_deref] [DW_OP_plus 8]
>> [DW_OP_deref] [DW_OP_plus 24]
>> +
>> +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
>> +
>> +%struct.__block_byref_x = type { i8*, %struct.__block_byref_x*, i32,
>> i32, i32 }
>> +
>> +; Function Attrs: nounwind ssp uwtable
>> +define void @foo() #0 {
>> +entry:
>> + %x = alloca %struct.__block_byref_x, align 8
>> + call void @llvm.dbg.declare(metadata !{%struct.__block_byref_x* %x},
>> metadata !12, metadata !22), !dbg !23
>> + %byref.isa = getelementptr inbounds %struct.__block_byref_x* %x, i32
>> 0, i32 0, !dbg !24
>> + store i8* null, i8** %byref.isa, !dbg !24
>> + %byref.forwarding = getelementptr inbounds %struct.__block_byref_x*
>> %x, i32 0, i32 1, !dbg !24
>> + store %struct.__block_byref_x* %x, %struct.__block_byref_x**
>> %byref.forwarding, !dbg !24
>> + %byref.flags = getelementptr inbounds %struct.__block_byref_x* %x, i32
>> 0, i32 2, !dbg !24
>> + store i32 0, i32* %byref.flags, !dbg !24
>> + %byref.size = getelementptr inbounds %struct.__block_byref_x* %x, i32
>> 0, i32 3, !dbg !24
>> + store i32 32, i32* %byref.size, !dbg !24
>> + %forwarding = getelementptr inbounds %struct.__block_byref_x* %x, i32
>> 0, i32 1, !dbg !25
>> + %0 = load %struct.__block_byref_x** %forwarding, !dbg !25
>> + %x1 = getelementptr inbounds %struct.__block_byref_x* %0, i32 0, i32
>> 4, !dbg !25
>> + %1 = load i32* %x1, align 4, !dbg !25
>> + call void @bar(i32 %1), !dbg !25
>> + %2 = bitcast %struct.__block_byref_x* %x to i8*, !dbg !26
>> + call void @_Block_object_dispose(i8* %2, i32 8) #3, !dbg !26
>> + ret void, !dbg !26
>> +}
>> +
>> +; Function Attrs: nounwind readnone
>> +declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
>> +
>> +declare void @bar(i32) #2
>> +
>> +declare void @_Block_object_dispose(i8*, i32)
>> +
>> +attributes #0 = { nounwind ssp uwtable sanitize_address
>> "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 }
>> +attributes #2 = { "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 #3 = { nounwind }
>> +
>> +!llvm.dbg.cu = !{!0}
>> +!llvm.module.flags = !{!8, !9, !10}
>> +!llvm.ident = !{!11}
>> +
>> +!0 = metadata !{metadata !"0x11\0012\00clang version 3.6.0 (trunk
>> 223120) (llvm/trunk 223119)\000\00\000\00\001", metadata !1, metadata !2,
>> metadata !2, metadata !3, metadata !2, metadata !2} ; [ DW_TAG_compile_unit
>> ] [/tmp/block.c] [DW_LANG_C99]
>> +!1 = metadata !{metadata !"block.c", metadata !"/tmp"}
>> +!2 = metadata !{}
>> +!3 = metadata !{metadata !4}
>> +!4 = metadata !{metadata
>> !"0x2e\00foo\00foo\00\003\000\001\000\000\000\000\003", metadata !1,
>> metadata !5, metadata !6, null, void ()* @foo, null, null, metadata !2} ; [
>> DW_TAG_subprogram ] [line 3] [def] [foo]
>> +!5 = metadata !{metadata !"0x29", metadata !1} ; [ DW_TAG_file_type ]
>> [/tmp/block.c]
>> +!6 = metadata !{metadata !"0x15\00\000\000\000\000\000\000", null, null,
>> null, metadata !7, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0,
>> size 0, align 0, offset 0] [from ]
>> +!7 = metadata !{null}
>> +!8 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
>> +!9 = metadata !{i32 2, metadata !"Debug Info Version", i32 2}
>> +!10 = metadata !{i32 1, metadata !"PIC Level", i32 2}
>> +!11 = metadata !{metadata !"clang version 3.6.0 (trunk 223120)
>> (llvm/trunk 223119)"}
>> +!12 = metadata !{metadata !"0x100\00x\004\000", metadata !4, metadata
>> !5, metadata !13} ; [ DW_TAG_auto_variable ] [x] [line 4]
>> +!13 = metadata !{metadata !"0x13\00\000\00224\000\000\0016\000",
>> metadata !1, metadata !5, null, metadata !14, null, null, null} ; [
>> DW_TAG_structure_type ] [line 0, size 224, align 0, offset 0] [def] [from ]
>> +!14 = metadata !{metadata !15, metadata !17, metadata !18, metadata !20,
>> metadata !21}
>> +!15 = metadata !{metadata !"0xd\00__isa\000\0064\0064\000\000", metadata
>> !1, metadata !5, metadata !16} ; [ DW_TAG_member ] [__isa] [line 0, size
>> 64, align 64, offset 0] [from ]
>> +!16 = metadata !{metadata !"0xf\00\000\0064\0064\000\000", null, null,
>> null} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from
>> ]
>> +!17 = metadata !{metadata !"0xd\00__forwarding\000\0064\0064\0064\000",
>> metadata !1, metadata !5, metadata !16} ; [ DW_TAG_member ] [__forwarding]
>> [line 0, size 64, align 64, offset 64] [from ]
>> +!18 = metadata !{metadata !"0xd\00__flags\000\0032\0032\00128\000",
>> metadata !1, metadata !5, metadata !19} ; [ DW_TAG_member ] [__flags] [line
>> 0, size 32, align 32, offset 128] [from int]
>> +!19 = 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]
>> +!20 = metadata !{metadata !"0xd\00__size\000\0032\0032\00160\000",
>> metadata !1, metadata !5, metadata !19} ; [ DW_TAG_member ] [__size] [line
>> 0, size 32, align 32, offset 160] [from int]
>> +!21 = metadata !{metadata !"0xd\00x\000\0032\0032\00192\000", metadata
>> !1, metadata !5, metadata !19} ; [ DW_TAG_member ] [x] [line 0, size 32,
>> align 32, offset 192] [from int]
>> +!22 = metadata !{metadata !"0x102\0034\008\006\0034\0024"} ; [
>> DW_TAG_expression ] [DW_OP_plus 8] [DW_OP_deref] [DW_OP_plus 24]
>> +!23 = metadata !{i32 4, i32 15, metadata !4, null}
>> +!24 = metadata !{i32 4, i32 3, metadata !4, null}
>> +!25 = metadata !{i32 5, i32 3, metadata !4, null}
>> +!26 = metadata !{i32 6, i32 1, metadata !4, null}
>>
>>
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--
Alexey Samsonov
vonosmas at gmail.com
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