[llvm] r223981 - A fix for PR21176.

Robinson, Paul Paul_Robinson at playstation.sony.com
Wed Dec 10 20:33:03 PST 2014


> -----Original Message-----
> From: Romanova, Katya
> Sent: Wednesday, December 10, 2014 8:07 PM
> To: Robinson, Paul; llvm-commits at cs.uiuc.edu
> Subject: RE: [llvm] r223981 - A fix for PR21176.
> 
> Hi Paul,
> That what my initial triaging showed too.
> 
> I was sitting and thinking what should I do now? Ask ppc developlers look
> at it? Look at it myself? Revert my change?

If it were me... I'd probably revert it, and file a bug against ppc using
this test case with the DWARF 4 part taken out.  When it's fixed, you can
put back your code change, and just add the DWARF 4 bit of the testcase.
--paulr

> 
> Katya.
> 
> -----Original Message-----
> From: Robinson, Paul
> Sent: Wednesday, December 10, 2014 8:01 PM
> To: Romanova, Katya; llvm-commits at cs.uiuc.edu
> Subject: RE: [llvm] r223981 - A fix for PR21176.
> 
> By chance, I got a bot failure notification that includes this revision.
> clang-ppc64-elf-linux2 is getting a failure because it doesn't have a
> location list at all; it resolves the variable to DW_AT_const_value (13).
> That is, it doesn't think that the value changes over the course of the
> function.  Maybe some ppc optimization is losing track of the variable?
> 
> Should be reproducible with llc -mtriple=powerpc64-unknown-linux and the
> dwarf version naturally is irrelevant.
> --paulr
> 
> > -----Original Message-----
> > From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-
> > bounces at cs.uiuc.edu] On Behalf Of Ekaterina Romanova
> > Sent: Wednesday, December 10, 2014 3:20 PM
> > To: llvm-commits at cs.uiuc.edu
> > Subject: [llvm] r223981 - A fix for PR21176.
> >
> > Author: kromanova
> > Date: Wed Dec 10 17:19:56 2014
> > New Revision: 223981
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=223981&view=rev
> > Log:
> > A fix for PR21176.
> >
> > DW_OP_const <const> doesn't describe a constant value, but a value at
> > a constant address.
> > The proper way to describe a constant value is DW_OP_constu <const>,
> > DW_OP_stack_value.
> >
> > Added DW_OP_stack_value to the stack.
> >
> > -This line, and those below, will be ignored--
> >
> > M    lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> > A    test/DebugInfo/incorrect-variable-debugloc1.ll
> >
> > Added:
> >     llvm/trunk/test/DebugInfo/incorrect-variable-debugloc1.ll
> > Modified:
> >     llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> >
> > Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> > URL: http://llvm.org/viewvc/llvm-
> > project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=223981&r1
> > =223
> > 980&r2=223981&view=diff
> > ======================================================================
> > ====
> > ====
> > --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
> > +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Wed Dec 10
> > +++ 17:19:56
> > 2014
> > @@ -1722,6 +1722,8 @@ void DwarfDebug::emitDebugLocValue(ByteS
> >        Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu");
> >        Streamer.EmitULEB128(Value.getInt());
> >      }
> > +   if (getDwarfVersion() >= 4)
> > +      Streamer.EmitInt8(dwarf::DW_OP_stack_value,
> > + "DW_OP_stack_value");
> >    } else if (Value.isLocation()) {
> >      MachineLocation Loc = Value.getLoc();
> >      DIExpression Expr = Value.getExpression();
> >
> > Added: llvm/trunk/test/DebugInfo/incorrect-variable-debugloc1.ll
> > URL: http://llvm.org/viewvc/llvm-
> > project/llvm/trunk/test/DebugInfo/incorrect-variable-
> > debugloc1.ll?rev=223981&view=auto
> > ======================================================================
> > ====
> > ====
> > --- llvm/trunk/test/DebugInfo/incorrect-variable-debugloc1.ll (added)
> > +++ llvm/trunk/test/DebugInfo/incorrect-variable-debugloc1.ll Wed Dec
> > +++ 10
> > 17:19:56 2014
> > @@ -0,0 +1,72 @@
> > +; REQUIRES: object-emission
> > +; RUN: %llc_dwarf -O2  -dwarf-version 2 -filetype=obj < %s | llvm-
> > dwarfdump - | FileCheck %s  --check-prefix=DWARF23
> > +; RUN: %llc_dwarf -O2  -dwarf-version 3 -filetype=obj < %s | llvm-
> > dwarfdump - | FileCheck %s  --check-prefix=DWARF23
> > +; RUN: %llc_dwarf -O2  -dwarf-version 4 -filetype=obj < %s | llvm-
> > dwarfdump - | FileCheck %s  --check-prefix=DWARF4
> > +
> > +; This is a test for PR21176.
> > +; DW_OP_const <const> doesn't describe a constant value, but a value
> > +at a
> > constant address.
> > +; The proper way to describe a constant value is DW_OP_constu
> > +<const>,
> > DW_OP_stack_value.
> > +
> > +; Generated with clang -S -emit-llvm -g -O2 test.cpp
> > +
> > +; extern int func();
> > +;
> > +; int main()
> > +; {
> > +;   volatile int c = 13;
> > +;   c = func();
> > +;   return c;
> > +; }
> > +
> > +; DWARF23: Location description: 10 0d {{$}} ; DWARF4: Location
> > +description: 10 0d 9f
> > +
> > +; Function Attrs: uwtable
> > +define i32 @main() #0 {
> > +entry:
> > +  %c = alloca i32, align 4
> > +  tail call void @llvm.dbg.value(metadata !15, i64 0, metadata !10,
> > metadata !16), !dbg !17
> > +  store volatile i32 13, i32* %c, align 4, !dbg !18  %call = tail
> > + call i32 @_Z4funcv(), !dbg !19  tail call void
> > + @llvm.dbg.value(metadata !{i32 %call}, i64 0, metadata
> > !10, metadata !16), !dbg !17
> > +  store volatile i32 %call, i32* %c, align 4, !dbg !19  tail call
> > + void @llvm.dbg.value(metadata !{i32* %c}, i64 0, metadata
> > !10, metadata !16), !dbg !17
> > +  %c.0.c.0. = load volatile i32* %c, align 4, !dbg !20
> > +  ret i32 %c.0.c.0., !dbg !20
> > +}
> > +
> > +declare i32 @_Z4funcv() #1
> > +
> > +; Function Attrs: nounwind readnone
> > +declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #2
> > +
> > +attributes #0 = { uwtable "less-precise-fpmad"="false"
> > +"no-frame-pointer-
> > elim"="false" "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 = { "less-precise-fpmad"="false" "no-frame-pointer-
> > elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false"
> > "stack- protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-
> > float"="false" }
> > +attributes #2 = { nounwind readnone }
> > +
> > +!llvm.dbg.cu = !{!0}
> > +!llvm.module.flags = !{!12, !13}
> > +!llvm.ident = !{!14}
> > +
> > +!0 = metadata !{metadata !"0x11\004\00clang version 3.6.0 (trunk
> > 223522)\001\00\000\00\001", metadata !1, metadata !2, metadata !2,
> > metadata !3, metadata !2, metadata !2} ; [ DW_TAG_compile_unit ]
> > [/home/kromanova/ngh/ToT_latest/llvm/test/DebugInfo/test.cpp]
> > [DW_LANG_C_plus_plus]
> > +!1 = metadata !{metadata !"test.cpp", metadata
> > !"/home/kromanova/ngh/ToT_latest/llvm/test/DebugInfo"}
> > +!2 = metadata !{}
> > +!3 = metadata !{metadata !4}
> > +!4 = metadata !{metadata
> > !"0x2e\00main\00main\00\003\000\001\000\000\00256\001\004", metadata
> > !1, metadata !5, metadata !6, null, i32 ()* @main, null, null,
> > metadata !9} ; [ DW_TAG_subprogram ] [line 3] [def] [scope 4] [main]
> > +!5 = metadata !{metadata !"0x29", metadata !1}    ; [ DW_TAG_file_type
> ]
> > [/home/kromanova/ngh/ToT_latest/llvm/test/DebugInfo/test.cpp]
> > +!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 !{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]
> > +!9 = metadata !{metadata !10}
> > +!10 = metadata !{metadata !"0x100\00c\005\000", metadata !4, metadata
> > +!5,
> > metadata !11} ; [ DW_TAG_auto_variable ] [c] [line 5]
> > +!11 = metadata !{metadata !"0x35\00\000\000\000\000\000", null, null,
> > metadata !8} ; [ DW_TAG_volatile_type ] [line 0, size 0, align 0,
> > offset 0] [from int]
> > +!12 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
> > +!13 = metadata !{i32 2, metadata !"Debug Info Version", i32 2}
> > +!14 = metadata !{metadata !"clang version 3.6.0 (trunk 223522)"}
> > +!15 = metadata !{i32 13}
> > +!16 = metadata !{metadata !"0x102"}               ; [ DW_TAG_expression
> ]
> > +!17 = metadata !{i32 5, i32 16, metadata !4, null}
> > +!18 = metadata !{i32 5, i32 3, metadata !4, null}
> > +!19 = metadata !{i32 6, i32 7, metadata !4, null}
> > +!20 = metadata !{i32 7, i32 3, metadata !4, null}
> > +
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits




More information about the llvm-commits mailing list