[llvm] r227827 - Debug Info: Relax assertion in isUnsignedDIType() to allow floats to be
Adrian Prantl
aprantl at apple.com
Mon Feb 2 11:24:02 PST 2015
> On Feb 2, 2015, at 10:39 AM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
>
> On Mon, Feb 2, 2015 at 10:31 AM, Adrian Prantl <aprantl at apple.com <mailto:aprantl at apple.com>> wrote:
> Author: adrian
> Date: Mon Feb 2 12:31:58 2015
> New Revision: 227827
>
> URL: http://llvm.org/viewvc/llvm-project?rev=227827&view=rev <http://llvm.org/viewvc/llvm-project?rev=227827&view=rev>
> Log:
> Debug Info: Relax assertion in isUnsignedDIType() to allow floats to be
> described by integer constants. This is a bit ugly, but if the source
> language allows arbitrary type casting, the debug info must follow suit.
>
> For example:
> void foo() {
> float a;
> *(int *)&a = 0;
> }
> For the curious: SROA replaces the float alloca with an i32 alloca, which
> is then optimized away and described via dbg.value(i32 0, ...).
>
> Not sure this is the right answer - even if the IR looks like that, it may be that we need to convert the constant back to the appropriate type before emitting the debug info?
Sounds reasonable, but if I understand the code in DwarfUnit correctly, there would not be any difference in the output:
} else if (DVInsn->getOperand(0).isFPImm())
addConstantFPValue(*VariableDie, DVInsn->getOperand(0));
->
/// addConstantFPValue - Add constant value entry in variable DIE.
void DwarfUnit::addConstantFPValue(DIE &Die, const ConstantFP *CFP) {
// Pass this down to addConstantValue as an unsigned bag of bits.
addConstantValue(Die, CFP->getValueAPF().bitcastToAPInt(), true);
}
->
void DwarfUnit::addConstantValue(DIE &Die, const APInt &Val, bool Unsigned) {
->
void DwarfUnit::addConstantValue(DIE &Die, const APInt &Val, DIType Ty) {
addConstantValue(Die, Val, isUnsignedDIType(DD, Ty));
}
-- adrian
>
> - David
>
>
> Added:
> llvm/trunk/test/DebugInfo/X86/float_const.ll
> Modified:
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=227827&r1=227826&r2=227827&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=227827&r1=227826&r2=227827&view=diff>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp Mon Feb 2 12:31:58 2015
> @@ -606,6 +606,7 @@ static bool isUnsignedDIType(DwarfDebug
> Encoding == dwarf::DW_ATE_unsigned_char ||
> Encoding == dwarf::DW_ATE_signed ||
> Encoding == dwarf::DW_ATE_signed_char ||
> + Encoding == dwarf::DW_ATE_float ||
> Encoding == dwarf::DW_ATE_UTF || Encoding == dwarf::DW_ATE_boolean ||
> (Ty.getTag() == dwarf::DW_TAG_unspecified_type &&
> Ty.getName() == "decltype(nullptr)")) &&
>
> Added: llvm/trunk/test/DebugInfo/X86/float_const.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/float_const.ll?rev=227827&view=auto <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/float_const.ll?rev=227827&view=auto>
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/X86/float_const.ll (added)
> +++ llvm/trunk/test/DebugInfo/X86/float_const.ll Mon Feb 2 12:31:58 2015
> @@ -0,0 +1,55 @@
> +; RUN: llc < %s -filetype=obj | llvm-dwarfdump -debug-dump=info - | FileCheck %s
> +; from (at -Os):
> +; void foo() {
> +; float a = 3.14;
> +; *(int *)&a = 0;
> +; }
> +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
> +target triple = "x86_64-apple-macosx10.10.0"
> +
> +; Function Attrs: nounwind optsize readnone uwtable
> +define void @foo() #0 {
> +entry:
> + tail call void @llvm.dbg.declare(metadata float* undef, metadata !13, metadata !19), !dbg !20
> + tail call void @llvm.dbg.value(metadata i32 1078523331, i64 0, metadata !13, metadata !19), !dbg !20
> + tail call void @llvm.dbg.value(metadata i32 0, i64 0, metadata !13, metadata !19), !dbg !20
> +; CHECK: DW_AT_const_value [DW_FORM_sdata] (0)
> +; CHECK-NEXT: DW_AT_name {{.*}}"a"
> + ret void, !dbg !21
> +}
> +
> +; Function Attrs: nounwind readnone
> +declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
> +
> +; Function Attrs: nounwind readnone
> +declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
> +
> +attributes #0 = { nounwind optsize readnone uwtable }
> +attributes #1 = { nounwind readnone }
> +
> +!llvm.dbg.cu <http://llvm.dbg.cu/> = !{!0}
> +!llvm.module.flags = !{!15, !16, !17}
> +!llvm.ident = !{!18}
> +
> +!0 = !{!"0x11\0012\00clang version 3.7.0 (trunk 227686)\001\00\000\00\001", !1, !2, !3, !6, !2, !2} ; [ DW_TAG_compile_unit ] [foo.c] [DW_LANG_C99]
> +!1 = !{!"foo.c", !""}
> +!2 = !{}
> +!3 = !{!4}
> +!4 = !{!"0xf\00\000\0064\0064\000\000", null, null, !5} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from int]
> +!5 = !{!"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]
> +!6 = !{!7}
> +!7 = !{!"0x2e\00foo\00foo\00\001\000\001\000\000\000\001\001", !8, !9, !10, null, void ()* @foo, null, null, !12} ; [ DW_TAG_subprogram ] [line 1] [def] [foo]
> +!8 = !{!"foo.c", !""}
> +!9 = !{!"0x29", !8} ; [ DW_TAG_file_type ]
> +!10 = !{!"0x15\00\000\000\000\000\000\000", null, null, null, !11, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
> +!11 = !{null}
> +!12 = !{!13}
> +!13 = !{!"0x100\00a\002\000", !7, !9, !14} ; [ DW_TAG_auto_variable ] [a] [line 2]
> +!14 = !{!"0x24\00float\000\0032\0032\000\000\004", null, null} ; [ DW_TAG_base_type ] [float] [line 0, size 32, align 32, offset 0, enc DW_ATE_float]
> +!15 = !{i32 2, !"Dwarf Version", i32 2}
> +!16 = !{i32 2, !"Debug Info Version", i32 2}
> +!17 = !{i32 1, !"PIC Level", i32 2}
> +!18 = !{!"clang version 3.7.0 (trunk 227686)"}
> +!19 = !{!"0x102"} ; [ DW_TAG_expression ]
> +!20 = !MDLocation(line: 2, column: 9, scope: !7)
> +!21 = !MDLocation(line: 4, column: 1, scope: !7)
>
>
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