[llvm] r195052 - Debug info: Let LowerDbgDeclare perfom the dbg.declare -> dbg.value
Eric Christopher
echristo at gmail.com
Mon Apr 14 16:16:45 PDT 2014
How does this interact with the other dbg_declare patch? We'd be
keeping vlas dbg_declares around still?
-eric
On Mon, Nov 18, 2013 at 3:04 PM, Adrian Prantl <aprantl at apple.com> wrote:
> Author: adrian
> Date: Mon Nov 18 17:04:38 2013
> New Revision: 195052
>
> URL: http://llvm.org/viewvc/llvm-project?rev=195052&view=rev
> Log:
> Debug info: Let LowerDbgDeclare perfom the dbg.declare -> dbg.value
> lowering only for load/stores to scalar allocas. The resulting values
> confuse the backend and don't add anything because we can describe
> array-allocas with a dbg.declare intrinsic just fine.
>
> rdar://problem/15464571
>
> Added:
> llvm/trunk/test/DebugInfo/ARM/lowerbdgdeclare_vla.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=195052&r1=195051&r2=195052&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/Local.cpp Mon Nov 18 17:04:38 2013
> @@ -1045,7 +1045,11 @@ bool llvm::LowerDbgDeclare(Function &F)
> for (SmallVectorImpl<DbgDeclareInst *>::iterator I = Dbgs.begin(),
> E = Dbgs.end(); I != E; ++I) {
> DbgDeclareInst *DDI = *I;
> - if (AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress())) {
> + AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress());
> + // If this is an alloca for a scalar variable, insert a dbg.value
> + // at each load and store to the alloca and erase the dbg.declare.
> + if (AI && !AI->isArrayAllocation()) {
> +
> // We only remove the dbg.declare intrinsic if all uses are
> // converted to dbg.value intrinsics.
> bool RemoveDDI = true;
>
> Added: llvm/trunk/test/DebugInfo/ARM/lowerbdgdeclare_vla.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/ARM/lowerbdgdeclare_vla.ll?rev=195052&view=auto
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/ARM/lowerbdgdeclare_vla.ll (added)
> +++ llvm/trunk/test/DebugInfo/ARM/lowerbdgdeclare_vla.ll Mon Nov 18 17:04:38 2013
> @@ -0,0 +1,102 @@
> +; RUN: opt -instcombine %s -S | FileCheck %s
> +;
> +; Generate me from:
> +; clang -cc1 -triple thumbv7-apple-ios7.0.0 -S -target-abi apcs-gnu -gdwarf-2 -Os test.c -o test.ll -emit-llvm
> +; void run(float r)
> +; {
> +; int count = r;
> +; float vla[count];
> +; vla[0] = r;
> +; for (int i = 0; i < count; i++)
> +; vla[i] /= r;
> +; }
> +; rdar://problem/15464571
> +;
> +; ModuleID = 'test.c'
> +target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32-S32"
> +target triple = "thumbv7-apple-ios8.0.0"
> +
> +; Function Attrs: nounwind optsize readnone
> +define void @run(float %r) #0 {
> +entry:
> + tail call void @llvm.dbg.declare(metadata !{float %r}, metadata !11), !dbg !22
> + %conv = fptosi float %r to i32, !dbg !23
> + tail call void @llvm.dbg.declare(metadata !{i32 %conv}, metadata !12), !dbg !23
> + %vla = alloca float, i32 %conv, align 4, !dbg !24
> + tail call void @llvm.dbg.declare(metadata !{float* %vla}, metadata !14), !dbg !24
> +; The VLA alloca should be described by a dbg.declare:
> +; CHECK: call void @llvm.dbg.declare(metadata !{float* %vla}, metadata ![[VLA:.*]])
> +; The VLA alloca and following store into the array should not be lowered to like this:
> +; CHECK-NOT: call void @llvm.dbg.value(metadata !{float %r}, i64 0, metadata ![[VLA]])
> +; the backend interprets this as "vla has the location of %r".
> + store float %r, float* %vla, align 4, !dbg !25, !tbaa !26
> + tail call void @llvm.dbg.value(metadata !2, i64 0, metadata !18), !dbg !30
> + %cmp8 = icmp sgt i32 %conv, 0, !dbg !30
> + br i1 %cmp8, label %for.body, label %for.end, !dbg !30
> +
> +for.body: ; preds = %entry, %for.body.for.body_crit_edge
> + %0 = phi float [ %.pre, %for.body.for.body_crit_edge ], [ %r, %entry ]
> + %i.09 = phi i32 [ %inc, %for.body.for.body_crit_edge ], [ 0, %entry ]
> + %arrayidx2 = getelementptr inbounds float* %vla, i32 %i.09, !dbg !31
> + %div = fdiv float %0, %r, !dbg !31
> + store float %div, float* %arrayidx2, align 4, !dbg !31, !tbaa !26
> + %inc = add nsw i32 %i.09, 1, !dbg !30
> + tail call void @llvm.dbg.value(metadata !{i32 %inc}, i64 0, metadata !18), !dbg !30
> + %exitcond = icmp eq i32 %inc, %conv, !dbg !30
> + br i1 %exitcond, label %for.end, label %for.body.for.body_crit_edge, !dbg !30
> +
> +for.body.for.body_crit_edge: ; preds = %for.body
> + %arrayidx2.phi.trans.insert = getelementptr inbounds float* %vla, i32 %inc
> + %.pre = load float* %arrayidx2.phi.trans.insert, align 4, !dbg !31, !tbaa !26
> + br label %for.body, !dbg !30
> +
> +for.end: ; preds = %for.body, %entry
> + ret void, !dbg !32
> +}
> +
> +; Function Attrs: nounwind readnone
> +declare void @llvm.dbg.declare(metadata, metadata) #1
> +
> +; Function Attrs: nounwind readnone
> +declare void @llvm.dbg.value(metadata, i64, metadata) #1
> +
> +attributes #0 = { nounwind optsize readnone "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
> +attributes #1 = { nounwind readnone }
> +
> +!llvm.dbg.cu = !{!0}
> +!llvm.module.flags = !{!20}
> +!llvm.ident = !{!21}
> +
> +!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.4 ", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [/Volumes/Data/radar/15464571/<unknown>] [DW_LANG_C99]
> +!1 = metadata !{metadata !"<unknown>", metadata !"/Volumes/Data/radar/15464571"}
> +!2 = metadata !{i32 0}
> +!3 = metadata !{metadata !4}
> +!4 = metadata !{i32 786478, metadata !5, metadata !6, metadata !"run", metadata !"run", metadata !"", i32 1, metadata !7, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void (float)* @run, null, null, metadata !10, i32 2} ; [ DW_TAG_subprogram ] [line 1] [def] [scope 2] [run]
> +!5 = metadata !{metadata !"test.c", metadata !"/Volumes/Data/radar/15464571"}
> +!6 = metadata !{i32 786473, metadata !5} ; [ DW_TAG_file_type ] [/Volumes/Data/radar/15464571/test.c]
> +!7 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !8, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
> +!8 = metadata !{null, metadata !9}
> +!9 = metadata !{i32 786468, null, null, metadata !"float", i32 0, i64 32, i64 32, i64 0, i32 0, i32 4} ; [ DW_TAG_base_type ] [float] [line 0, size 32, align 32, offset 0, enc DW_ATE_float]
> +!10 = metadata !{metadata !11, metadata !12, metadata !14, metadata !18}
> +!11 = metadata !{i32 786689, metadata !4, metadata !"r", metadata !6, i32 16777217, metadata !9, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [r] [line 1]
> +!12 = metadata !{i32 786688, metadata !4, metadata !"count", metadata !6, i32 3, metadata !13, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [count] [line 3]
> +!13 = 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]
> +!14 = metadata !{i32 786688, metadata !4, metadata !"vla", metadata !6, i32 4, metadata !15, i32 8192, i32 0} ; [ DW_TAG_auto_variable ] [vla] [line 4]
> +!15 = metadata !{i32 786433, null, null, metadata !"", i32 0, i64 0, i64 32, i32 0, i32 0, metadata !9, metadata !16, i32 0, null, null, null} ; [ DW_TAG_array_type ] [line 0, size 0, align 32, offset 0] [from float]
> +!16 = metadata !{metadata !17}
> +!17 = metadata !{i32 786465, i64 0, i64 -1} ; [ DW_TAG_subrange_type ] [unbounded]
> +!18 = metadata !{i32 786688, metadata !19, metadata !"i", metadata !6, i32 6, metadata !13, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [i] [line 6]
> +!19 = metadata !{i32 786443, metadata !5, metadata !4, i32 6, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [/Volumes/Data/radar/15464571/test.c]
> +!20 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
> +!21 = metadata !{metadata !"clang version 3.4 "}
> +!22 = metadata !{i32 1, i32 0, metadata !4, null}
> +!23 = metadata !{i32 3, i32 0, metadata !4, null}
> +!24 = metadata !{i32 4, i32 0, metadata !4, null}
> +!25 = metadata !{i32 5, i32 0, metadata !4, null}
> +!26 = metadata !{metadata !27, metadata !27, i64 0}
> +!27 = metadata !{metadata !"float", metadata !28, i64 0}
> +!28 = metadata !{metadata !"omnipotent char", metadata !29, i64 0}
> +!29 = metadata !{metadata !"Simple C/C++ TBAA"}
> +!30 = metadata !{i32 6, i32 0, metadata !19, null}
> +!31 = metadata !{i32 7, i32 0, metadata !19, null}
> +!32 = metadata !{i32 8, i32 0, metadata !4, null} ; [ DW_TAG_imported_declaration ]
>
>
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