[llvm] r205529 - Fix for PR 19261:

Daniel Sanders Daniel.Sanders at imgtec.com
Thu Apr 3 07:03:13 PDT 2014


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 @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




More information about the llvm-commits mailing list