[llvm] r205529 - Fix for PR 19261:
Daniel Sanders
Daniel.Sanders at imgtec.com
Fri Apr 4 03:31:27 PDT 2014
I've just had a quick look and it appears that the prologue_end marker is appearing at the start of the prologue in this case.
# BB#0: # %entry
.loc 1 1 0 prologue_end # test.c:1:0
addiu $sp, $sp, -8
$tmp0:
I'm not familiar with the debug info code but I think the problem is that we don't set the MachineInstr::FrameSetup on any instruction in the prologue. Does that sound right to you?
> -----Original Message-----
> From: Eric Christopher [mailto:echristo at gmail.com]
> Sent: 03 April 2014 18:54
> To: Daniel Sanders
> Cc: llvm-commits at cs.uiuc.edu
> Subject: Re: [llvm] r205529 - Fix for PR 19261:
>
> I've relaxed the testcase for now and I think it works for mips (I tested it with
> -march=mips on llc by hand). I'll keep an eye out.
>
> FWIW there's something odd going on for mips here. It has two line table
> entries for address 0. Probably worth taking a look at some point.
>
> -eric
>
> On Thu, Apr 3, 2014 at 10:08 AM, Eric Christopher <echristo at gmail.com>
> wrote:
> > I can see it on a couple of the others as well. I'll take a look. I
> > think the testcase may just need to be relaxed.
> >
> > On Apr 3, 2014 7:03 AM, "Daniel Sanders" <Daniel.Sanders at imgtec.com>
> wrote:
> >>
> >> Hi Eric,
> >>
> >> I think this commit caused llvm-mips-linux buildbot to turn red and I
> >> don't think it has sent an email (I'm also on the blamelist and I
> >> haven't received one).
> >> The build is
> >> http://lab.llvm.org:8011/builders/llvm-mips-linux/builds/8028
> >>
> >> I've re-run the test on an X86 with -march=mips added to the llc
> >> command and it seems that an extra entry appears in the line
> >> information between the CHECK and the CHECK-NEXT:
> >> Address Line Column File ISA Discriminator Flags
> >> ------------------ ------ ------ ------ --- ------------- -------------
> >> 0x0000000000000000 1 0 1 0 0 is_stmt
> >> 0x0000000000000000 1 0 1 0 0 is_stmt
> >> prologue_end <--- extra line
> >> 0x0000000000000010 2 0 1 0 0 is_stmt
> >> 0x0000000000000018 4 0 1 0 0 is_stmt
> >> 0x0000000000000020 6 0 1 0 0 is_stmt
> >> 0x0000000000000034 6 0 1 0 0 is_stmt
> >> end_sequence
> >>
> >> > -----Original Message-----
> >> > From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-
> >> > bounces at cs.uiuc.edu] On Behalf Of Eric Christopher
> >> > Sent: 03 April 2014 13:12
> >> > To: llvm-commits at cs.uiuc.edu
> >> > Subject: [llvm] r205529 - Fix for PR 19261:
> >> >
> >> > Author: echristo
> >> > Date: Thu Apr 3 07:11:51 2014
> >> > New Revision: 205529
> >> >
> >> > URL: http://llvm.org/viewvc/llvm-project?rev=205529&view=rev
> >> > Log:
> >> > Fix for PR 19261:
> >> >
> >> > llc doesn't generate nodes for unconditional fall-through branches
> >> > for targets without FastISel implementation (X86 has it, but can be
> >> > disabled by
> >> > "-fast-isel=false") in SelectionDAGBuilder::visitBr().
> >> >
> >> > So for line 4 in the following testcase
> >> >
> >> > 1: void foo(int i){
> >> > 2: switch(i){
> >> > 3: default:
> >> > 4: break;
> >> > 5: }
> >> > 6: return;
> >> > 7: }
> >> >
> >> > there is no corresponding line in .debug_line section, and a
> >> > debugger cannot set a breakpoint at line 4.
> >> >
> >> > Fix this by always emitting a branch when we're not optimizing and
> >> > add a testcase to ensure that there's code on every line we'd want to
> break.
> >> >
> >> > Patch by Daniil Fukalov.
> >> >
> >> > Added:
> >> > llvm/trunk/test/DebugInfo/unconditional-branch.ll
> >> > Modified:
> >> > llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> >> >
> >> > Modified:
> >> > llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> >> > URL: http://llvm.org/viewvc/llvm-
> >> >
> project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> >> > ?re v=205529&r1=205528&r2=205529&view=diff
> >> >
> ==========================================================
> >> > ====================
> >> > --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> >> > (original)
> >> > +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> Thu
> >> > Apr
> >> > +++ 3 07:11:51 2014
> >> > @@ -1571,8 +1571,9 @@ void SelectionDAGBuilder::visitBr(const
> >> > // Update machine-CFG edges.
> >> > BrMBB->addSuccessor(Succ0MBB);
> >> >
> >> > - // If this is not a fall-through branch, emit the branch.
> >> > - if (Succ0MBB != NextBlock)
> >> > + // If this is not a fall-through branch or optimizations are
> >> > switched off,
> >> > + // emit the branch.
> >> > + if (Succ0MBB != NextBlock || TM.getOptLevel() ==
> >> > + CodeGenOpt::None)
> >> > DAG.setRoot(DAG.getNode(ISD::BR, getCurSDLoc(),
> >> > MVT::Other, getControlRoot(),
> >> > DAG.getBasicBlock(Succ0MBB)));
> >> >
> >> > Added: llvm/trunk/test/DebugInfo/unconditional-branch.ll
> >> > URL: http://llvm.org/viewvc/llvm-
> >> > project/llvm/trunk/test/DebugInfo/unconditional-
> >> > branch.ll?rev=205529&view=auto
> >> >
> ==========================================================
> >> > ====================
> >> > --- llvm/trunk/test/DebugInfo/unconditional-branch.ll (added)
> >> > +++ llvm/trunk/test/DebugInfo/unconditional-branch.ll Thu Apr 3
> >> > +++ 07:11:51 2014
> >> > @@ -0,0 +1,64 @@
> >> > +; REQUIRES: object-emission
> >> > +; PR 19261
> >> > +
> >> > +; RUN: %llc_dwarf -fast-isel=false -O0 -filetype=obj < %s > %t ; RUN:
> >> > +llvm-dwarfdump %t | FileCheck %s
> >> > +
> >> > +; CHECK: {{0x[0-9a-f]+}} 1 0 1 0 0
> >> > is_stmt
> >> > +; CHECK-NEXT: {{0x[0-9a-f]+}} 2 0 1 0 0
> >> > is_stmt
> >> > +; CHECK-NEXT: {{0x[0-9a-f]+}} 4 0 1 0 0
> >> > is_stmt
> >> > +
> >> > +; IR generated from clang -O0 -g with the following source:
> >> > +;void foo(int i){
> >> > +; switch(i){
> >> > +; default:
> >> > +; break;
> >> > +; }
> >> > +; return;
> >> > +;}
> >> > +
> >> > +; Function Attrs: nounwind
> >> > +define void @foo(i32 %i) #0 {
> >> > +entry:
> >> > + %i.addr = alloca i32, align 4
> >> > + store i32 %i, i32* %i.addr, align 4
> >> > + call void @llvm.dbg.declare(metadata !{i32* %i.addr}, metadata
> >> > +!12), !dbg !13
> >> > + %0 = load i32* %i.addr, align 4, !dbg !14
> >> > + switch i32 %0, label %sw.default [
> >> > + ], !dbg !14
> >> > +
> >> > +sw.default: ; preds = %entry
> >> > + br label %sw.epilog, !dbg !15
> >> > +
> >> > +sw.epilog: ; preds = %sw.default
> >> > + ret void, !dbg !17
> >> > +}
> >> > +
> >> > +; Function Attrs: nounwind readnone declare void
> >> > + at llvm.dbg.declare(metadata, metadata) #1
> >> > +
> >> > +attributes #0 = { nounwind "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 !{i32 786449, metadata !1, i32 12, metadata !"clang
> >> > +version 3.5.0 (204712)", i1 false, metadata !"", i32 0, metadata
> >> > +!2, metadata !2, metadata !3, metadata !2, metadata !2, metadata
> >> > +!"", i32 1} ; [ DW_TAG_compile_unit ] [D:\work\EPRs\396363/test.c]
> >> > [DW_LANG_C99]
> >> > +!1 = metadata !{metadata !"test.c", metadata
> >> > +!"D:\5Cwork\5CEPRs\5C396363"}
> >> > +!2 = metadata !{}
> >> > +!3 = metadata !{metadata !4}
> >> > +!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata
> >> > +!"foo",
> >> > metadata !"foo", metadata !"", i32 1, metadata !6, i1 false, i1
> >> > true,
> >> > i32 0, i32 0,
> >> > null, i32 256, i1 false, void (i32)* @foo, null, null, metadata !2,
> >> > i32 1} ; [ DW_TAG_subprogram ] [line 1] [def] [foo]
> >> > +!5 = metadata !{i32 786473, metadata !1} ; [ DW_TAG_file_type
> >> > ]
> >> > [D:\work\EPRs\396363/test.c]
> >> > +!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64
> >> > +0,
> >> > +i64 0, i64 0, i32 0, null, metadata !7, i32 0, null, null, null} ;
> >> > +[ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0]
> >> > +[from ]
> >> > +!7 = metadata !{null, metadata !8}
> >> > +!8 = metadata !{i32 786468, null, null, metadata !"int", i32 0,
> >> > +i64 32,
> >> > +i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0,
> >> > +size 32, align 32, offset 0, enc DW_ATE_signed]
> >> > +!9 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
> >> > +!10 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
> >> > +!11 = metadata !{metadata !"clang version 3.5.0 (204712)"}
> >> > +!12 = metadata !{i32 786689, metadata !4, metadata !"i", metadata
> >> > +!5,
> >> > +i32 16777217, metadata !8, i32 0, i32 0} ; [ DW_TAG_arg_variable ]
> >> > +[i] [line 1]
> >> > +!13 = metadata !{i32 1, i32 0, metadata !4, null}
> >> > +!14 = metadata !{i32 2, i32 0, metadata !4, null}
> >> > +!15 = metadata !{i32 4, i32 0, metadata !16, null}
> >> > +!16 = metadata !{i32 786443, metadata !1, metadata !4, i32 2, i32
> >> > +0,
> >> > +i32 0, i32 0} ; [ DW_TAG_lexical_block ]
> >> > +[D:\work\EPRs\396363/test.c]
> >> > +!17 = metadata !{i32 6, i32 0, metadata !4, null}
> >> >
> >> >
> >> > _______________________________________________
> >> > llvm-commits mailing list
> >> > llvm-commits at cs.uiuc.edu
> >> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
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