[llvm] r224739 - Debug info: Teach SROA how to update debug info for fragmented variables.
Adrian Prantl
aprantl at apple.com
Mon Dec 22 14:26:00 PST 2014
Author: adrian
Date: Mon Dec 22 16:26:00 2014
New Revision: 224739
URL: http://llvm.org/viewvc/llvm-project?rev=224739&view=rev
Log:
Debug info: Teach SROA how to update debug info for fragmented variables.
This allows us to generate debug info for extremely advanced code such as
typedef struct { long int a; int b;} S;
int foo(S s) {
return s.b;
}
which at -O1 on x86_64 is codegen'd into
define i32 @foo(i64 %s.coerce0, i32 %s.coerce1) #0 {
ret i32 %s.coerce1, !dbg !24
}
with this patch we emit the following debug info for this
TAG_formal_parameter [3]
AT_location( 0x00000000
0x0000000000000000 - 0x0000000000000006: rdi, piece 0x00000008, rsi, piece 0x00000004
0x0000000000000006 - 0x0000000000000008: rdi, piece 0x00000008, rax, piece 0x00000004 )
AT_name( "s" )
AT_decl_file( "/Volumes/Data/llvm/_build.ninja.release/test.c" )
Thanks to chandlerc, dblaikie, and echristo for their feedback on all
previous iterations of this patch!
Added:
llvm/trunk/test/DebugInfo/X86/sroasplit-1.ll
llvm/trunk/test/DebugInfo/X86/sroasplit-2.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/SROA.cpp
llvm/trunk/test/DebugInfo/X86/array2.ll
Modified: llvm/trunk/lib/Transforms/Scalar/SROA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SROA.cpp?rev=224739&r1=224738&r2=224739&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SROA.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SROA.cpp Mon Dec 22 16:26:00 2014
@@ -953,6 +953,10 @@ class SROA : public FunctionPass {
/// currently in the promotable queue.
SetVector<SelectInst *, SmallVector<SelectInst *, 2>> SpeculatableSelects;
+ /// Debug intrinsics do not show up as regular uses in the
+ /// IR. This side-table holds the missing use edges.
+ DenseMap<AllocaInst *, DbgDeclareInst *> DbgDeclares;
+
public:
SROA(bool RequiresDomTree = true)
: FunctionPass(ID), RequiresDomTree(RequiresDomTree), C(nullptr),
@@ -3230,6 +3234,27 @@ bool SROA::rewritePartition(AllocaInst &
new AllocaInst(SliceTy, nullptr, Alignment,
AI.getName() + ".sroa." + Twine(B - AS.begin()), &AI);
++NumNewAllocas;
+
+ // Migrate debug information from the old alloca to the new alloca
+ // and the individial slices.
+ if (DbgDeclareInst *DbgDecl = DbgDeclares.lookup(&AI)) {
+ DIVariable Var(DbgDecl->getVariable());
+ DIExpression Piece;
+ DIBuilder DIB(*AI.getParent()->getParent()->getParent(),
+ /*AllowUnresolved*/ false);
+ // Create a piece expression describing the slice, if the new slize is
+ // smaller than the old alloca or the old alloca already was described
+ // with a piece. It would be even better to just compare against the size
+ // of the type described in the debug info, but then we would need to
+ // build an expensive DIRefMap.
+ if (SliceSize < DL->getTypeAllocSize(AI.getAllocatedType()) ||
+ DIExpression(DbgDecl->getExpression()).isVariablePiece())
+ Piece = DIB.createPieceExpression(BeginOffset, SliceSize);
+ Instruction *NewDDI = DIB.insertDeclare(NewAI, Var, Piece, &AI);
+ NewDDI->setDebugLoc(DbgDecl->getDebugLoc());
+ DbgDeclares.insert(std::make_pair(NewAI, cast<DbgDeclareInst>(NewDDI)));
+ DeadInsts.insert(DbgDecl);
+ }
}
DEBUG(dbgs() << "Rewriting alloca partition "
@@ -3680,9 +3705,13 @@ bool SROA::runOnFunction(Function &F) {
BasicBlock &EntryBB = F.getEntryBlock();
for (BasicBlock::iterator I = EntryBB.begin(), E = std::prev(EntryBB.end());
- I != E; ++I)
+ I != E; ++I) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
Worklist.insert(AI);
+ else if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I))
+ if (auto AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress()))
+ DbgDeclares.insert(std::make_pair(AI, DDI));
+ }
bool Changed = false;
// A set of deleted alloca instruction pointers which should be removed from
Modified: llvm/trunk/test/DebugInfo/X86/array2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/array2.ll?rev=224739&r1=224738&r2=224739&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/array2.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/array2.ll Mon Dec 22 16:26:00 2014
@@ -13,12 +13,12 @@
; }
;
; RUN: opt %s -O2 -S -o - | FileCheck %s
-; Test that we do not lower dbg.declares for arrays.
+; Test that we correctly lower dbg.declares for arrays.
;
; CHECK: define i32 @main
-; CHECK: call void @llvm.dbg.value
-; CHECK: call void @llvm.dbg.value
-; CHECK: call void @llvm.dbg.declare
+; CHECK: call void @llvm.dbg.value(metadata i32 42, i64 0, metadata ![[ARRAY:[0-9]+]], metadata ![[EXPR:[0-9]+]])
+; CHECK: ![[ARRAY]] = {{.*}}; [ DW_TAG_auto_variable ] [array] [line 6]
+; CHECK: ![[EXPR]] = {{.*}}; [ DW_TAG_expression ] [DW_OP_piece offset=0, size=4]
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.9.0"
Added: llvm/trunk/test/DebugInfo/X86/sroasplit-1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/sroasplit-1.ll?rev=224739&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/sroasplit-1.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/sroasplit-1.ll Mon Dec 22 16:26:00 2014
@@ -0,0 +1,97 @@
+; RUN: opt %s -sroa -verify -S -o - | FileCheck %s
+;
+; Test that we can partial emit debug info for aggregates repeatedly
+; split up by SROA.
+;
+; // Compile with -O1
+; typedef struct {
+; int a;
+; long int b;
+; } Inner;
+;
+; typedef struct {
+; Inner inner[2];
+; } Outer;
+;
+; int foo(Outer outer) {
+; Inner i1 = outer.inner[1];
+; return i1.a;
+; }
+;
+
+; Verify that SROA creates a variable piece when splitting i1.
+; CHECK: %[[I1:.*]] = alloca [12 x i8], align 4
+; CHECK: call void @llvm.dbg.declare(metadata [12 x i8]* %[[I1]], metadata ![[VAR:[0-9]+]], metadata ![[PIECE1:[0-9]+]])
+; CHECK: call void @llvm.dbg.value(metadata i32 %[[A:.*]], i64 0, metadata ![[VAR]], metadata ![[PIECE2:[0-9]+]])
+; CHECK: ret i32 %[[A]]
+; Read Var and Piece:
+; CHECK: ![[VAR]] = {{.*}} ; [ DW_TAG_auto_variable ] [i1] [line 11]
+; CHECK: ![[PIECE1]] = {{.*}} ; [ DW_TAG_expression ] [DW_OP_piece offset=4, size=12]
+; CHECK: ![[PIECE2]] = {{.*}} ; [ DW_TAG_expression ] [DW_OP_piece offset=0, size=4]
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.9.0"
+
+%struct.Outer = type { [2 x %struct.Inner] }
+%struct.Inner = type { i32, i64 }
+
+; Function Attrs: nounwind ssp uwtable
+define i32 @foo(%struct.Outer* byval align 8 %outer) #0 {
+entry:
+ %i1 = alloca %struct.Inner, align 8
+ call void @llvm.dbg.declare(metadata %struct.Outer* %outer, metadata !25, metadata !2), !dbg !26
+ call void @llvm.dbg.declare(metadata %struct.Inner* %i1, metadata !27, metadata !2), !dbg !28
+ %inner = getelementptr inbounds %struct.Outer* %outer, i32 0, i32 0, !dbg !28
+ %arrayidx = getelementptr inbounds [2 x %struct.Inner]* %inner, i32 0, i64 1, !dbg !28
+ %0 = bitcast %struct.Inner* %i1 to i8*, !dbg !28
+ %1 = bitcast %struct.Inner* %arrayidx to i8*, !dbg !28
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %1, i64 16, i32 8, i1 false), !dbg !28
+ %a = getelementptr inbounds %struct.Inner* %i1, i32 0, i32 0, !dbg !29
+ %2 = load i32* %a, align 4, !dbg !29
+ ret i32 %2, !dbg !29
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) #2
+
+attributes #0 = { nounwind ssp uwtable }
+attributes #1 = { nounwind readnone }
+attributes #2 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!22, !23}
+!llvm.ident = !{!24}
+
+!0 = !{!"0x11\0012\00clang version 3.5.0 \000\00\000\00\001", !1, !2, !2, !3, !2, !2} ; [ DW_TAG_compile_unit ] [ DW_TAG_compile_unit ] [sroasplit-1.c] [DW_LANG_C99]
+!1 = !{!"sroasplit-1.c", !""}
+!2 = !{}
+!3 = !{!4}
+!4 = !{!"0x2e\00foo\00foo\00\0010\000\001\000\006\00256\000\0010", !1, !5, !6, null, i32 (%struct.Outer*)* @foo, null, null, !2} ; [ DW_TAG_subprogram ] [ DW_TAG_subprogram ] [line 10] [def] [foo]
+!5 = !{!"0x29", !1} ; [ DW_TAG_file_type ] [ DW_TAG_file_type ] [sroasplit-1.c]
+!6 = !{!"0x15\00\000\000\000\000\000\000", i32 0, null, null, !7, null, null, null} ; [ DW_TAG_subroutine_type ] [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!7 = !{!8, !9}
+!8 = !{!"0x24\00int\000\0032\0032\000\000\005", null, null} ; [ DW_TAG_base_type ] [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!9 = !{!"0x16\00Outer\008\000\000\000\000", !1, null, !10} ; [ DW_TAG_typedef ] [ DW_TAG_typedef ] [Outer] [line 8, size 0, align 0, offset 0] [from ]
+!10 = !{!"0x13\00\006\00256\0064\000\000\000", !1, null, null, !11, null, null, null} ; [ DW_TAG_structure_type ] [line 6, size 256, align 64, offset 0] [def] [from ]
+!11 = !{!12}
+!12 = !{!"0xd\00inner\007\00256\0064\000\000", !1, !10, !13} ; [ DW_TAG_member ] [inner] [line 7, size 256, align 64, offset 0] [from ]
+!13 = !{!"0x1\00\000\00256\0064\000\000", null, null, !14, !20, i32 0, null, null, null} ; [ DW_TAG_array_type ] [line 0, size 256, align 64, offset 0] [from Inner]
+!14 = !{!"0x16\00Inner\004\000\000\000\000", !1, null, !15} ; [ DW_TAG_typedef ] [ DW_TAG_typedef ] [Inner] [line 4, size 0, align 0, offset 0] [from ]
+!15 = !{!"0x13\00\001\00128\0064\000\000\000", !1, null, null, !16, null, null, null} ; [ DW_TAG_structure_type ] [line 1, size 128, align 64, offset 0] [def] [from ]
+!16 = !{!17, !18}
+!17 = !{!"0xd\00a\002\0032\0032\000\000", !1, !15, !8} ; [ DW_TAG_member ] [a] [line 2, size 32, align 32, offset 0] [from int]
+!18 = !{!"0xd\00b\003\0064\0064\0064\000", !1, !15, !19} ; [ DW_TAG_member ] [b] [line 3, size 64, align 64, offset 64] [from long int]
+!19 = !{!"0x24\00long int\000\0064\0064\000\000\005", null, null} ; [ DW_TAG_base_type ] [ DW_TAG_base_type ] [long int] [line 0, size 64, align 64, offset 0, enc DW_ATE_signed]
+!20 = !{!21}
+!21 = !{!"0x21\000\002"} ; [ DW_TAG_subrange_type ] [0, 1]
+!22 = !{i32 2, !"Dwarf Version", i32 2}
+!23 = !{i32 1, !"Debug Info Version", i32 2}
+!24 = !{!"clang version 3.5.0 "}
+!25 = !{!"0x101\00outer\0016777226\000", !4, !5, !9} ; [ DW_TAG_arg_variable ] [ DW_TAG_arg_variable ] [outer] [line 10]
+!26 = !{i32 10, i32 0, !4, null}
+!27 = !{!"0x100\00i1\0011\000", !4, !5, !14} ; [ DW_TAG_auto_variable ] [ DW_TAG_auto_variable ] [i1] [line 11]
+!28 = !{i32 11, i32 0, !4, null}
+!29 = !{i32 12, i32 0, !4, null}
Added: llvm/trunk/test/DebugInfo/X86/sroasplit-2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/sroasplit-2.ll?rev=224739&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/sroasplit-2.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/sroasplit-2.ll Mon Dec 22 16:26:00 2014
@@ -0,0 +1,102 @@
+; RUN: opt %s -sroa -verify -S -o - | FileCheck %s
+;
+; Test that we can partial emit debug info for aggregates repeatedly
+; split up by SROA.
+;
+; // Compile with -O1
+; typedef struct {
+; int a;
+; int b;
+; } Inner;
+;
+; typedef struct {
+; Inner inner[2];
+; } Outer;
+;
+; int foo(Outer outer) {
+; Inner i1 = outer.inner[1];
+; return i1.a;
+; }
+;
+
+; Verify that SROA creates a variable piece when splitting i1.
+; CHECK: call void @llvm.dbg.value(metadata i64 %outer.coerce0, i64 0, metadata ![[O:[0-9]+]], metadata ![[PIECE1:[0-9]+]]),
+; CHECK: call void @llvm.dbg.value(metadata i64 %outer.coerce1, i64 0, metadata ![[O]], metadata ![[PIECE2:[0-9]+]]),
+; CHECK: call void @llvm.dbg.value({{.*}}, i64 0, metadata ![[I1:[0-9]+]], metadata ![[PIECE3:[0-9]+]]),
+; CHECK-DAG: ![[O]] = {{.*}} [ DW_TAG_arg_variable ] [outer] [line 10]
+; CHECK-DAG: ![[PIECE1]] = {{.*}} [ DW_TAG_expression ] [DW_OP_piece offset=0, size=8]
+; CHECK-DAG: ![[PIECE2]] = {{.*}} [ DW_TAG_expression ] [DW_OP_piece offset=8, size=8]
+; CHECK-DAG: ![[I1]] = {{.*}} [ DW_TAG_auto_variable ] [i1] [line 11]
+; CHECK-DAG: ![[PIECE3]] = {{.*}} [ DW_TAG_expression ] [DW_OP_piece offset=0, size=4]
+
+; ModuleID = 'sroasplit-2.c'
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.9.0"
+
+%struct.Outer = type { [2 x %struct.Inner] }
+%struct.Inner = type { i32, i32 }
+
+; Function Attrs: nounwind ssp uwtable
+define i32 @foo(i64 %outer.coerce0, i64 %outer.coerce1) #0 {
+ %outer = alloca %struct.Outer, align 8
+ %i1 = alloca %struct.Inner, align 4
+ %1 = bitcast %struct.Outer* %outer to { i64, i64 }*
+ %2 = getelementptr { i64, i64 }* %1, i32 0, i32 0
+ store i64 %outer.coerce0, i64* %2
+ %3 = getelementptr { i64, i64 }* %1, i32 0, i32 1
+ store i64 %outer.coerce1, i64* %3
+ call void @llvm.dbg.declare(metadata %struct.Outer* %outer, metadata !24, metadata !2), !dbg !25
+ call void @llvm.dbg.declare(metadata %struct.Inner* %i1, metadata !26, metadata !2), !dbg !27
+ %4 = getelementptr inbounds %struct.Outer* %outer, i32 0, i32 0, !dbg !27
+ %5 = getelementptr inbounds [2 x %struct.Inner]* %4, i32 0, i64 1, !dbg !27
+ %6 = bitcast %struct.Inner* %i1 to i8*, !dbg !27
+ %7 = bitcast %struct.Inner* %5 to i8*, !dbg !27
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* %6, i8* %7, i64 8, i32 4, i1 false), !dbg !27
+ %8 = getelementptr inbounds %struct.Inner* %i1, i32 0, i32 0, !dbg !28
+ %9 = load i32* %8, align 4, !dbg !28
+ ret i32 %9, !dbg !28
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) #2
+
+attributes #0 = { nounwind ssp uwtable "no-frame-pointer-elim"="true" }
+attributes #1 = { nounwind readnone }
+attributes #2 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!21, !22}
+!llvm.ident = !{!23}
+
+!0 = !{!"0x11\0012\00clang version 3.5.0 \000\00\000\00\001", !1, !2, !2, !3, !2, !2} ; [ DW_TAG_compile_unit ] [ DW_TAG_compile_unit ] [sroasplit-2.c] [DW_LANG_C99]
+!1 = !{!"sroasplit-2.c", !""}
+!2 = !{}
+!3 = !{!4}
+!4 = !{!"0x2e\00foo\00foo\00\0010\000\001\000\006\00256\000\0010", !1, !5, !6, null, i32 (i64, i64)* @foo, null, null, !2} ; [ DW_TAG_subprogram ] [ DW_TAG_subprogram ] [line 10] [def] [foo]
+!5 = !{!"0x29", !1} ; [ DW_TAG_file_type ] [ DW_TAG_file_type ] [sroasplit-2.c]
+!6 = !{!"0x15\00\000\000\000\000\000\000", i32 0, null, null, !7, null, null, null} ; [ DW_TAG_subroutine_type ] [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!7 = !{!8, !9}
+!8 = !{!"0x24\00int\000\0032\0032\000\000\005", null, null} ; [ DW_TAG_base_type ] [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!9 = !{!"0x16\00Outer\008\000\000\000\000", !1, null, !10} ; [ DW_TAG_typedef ] [ DW_TAG_typedef ] [Outer] [line 8, size 0, align 0, offset 0] [from ]
+!10 = !{!"0x13\00\006\00128\0032\000\000\000", !1, null, null, !11, null, null, null} ; [ DW_TAG_structure_type ] [line 6, size 128, align 32, offset 0] [def] [from ]
+!11 = !{!12}
+!12 = !{!"0xd\00inner\007\00128\0032\000\000", !1, !10, !13} ; [ DW_TAG_member ] [inner] [line 7, size 128, align 32, offset 0] [from ]
+!13 = !{!"0x1\00\000\00128\0032\000\000", null, null, !14, !19, i32 0, null, null, null} ; [ DW_TAG_array_type ] [line 0, size 128, align 32, offset 0] [from Inner]
+!14 = !{!"0x16\00Inner\004\000\000\000\000", !1, null, !15} ; [ DW_TAG_typedef ] [ DW_TAG_typedef ] [Inner] [line 4, size 0, align 0, offset 0] [from ]
+!15 = !{!"0x13\00\001\0064\0032\000\000\000", !1, null, null, !16, null, null, null} ; [ DW_TAG_structure_type ] [line 1, size 64, align 32, offset 0] [def] [from ]
+!16 = !{!17, !18}
+!17 = !{!"0xd\00a\002\0032\0032\000\000", !1, !15, !8} ; [ DW_TAG_member ] [a] [line 2, size 32, align 32, offset 0] [from int]
+!18 = !{!"0xd\00b\003\0032\0032\0032\000", !1, !15, !8} ; [ DW_TAG_member ] [b] [line 3, size 32, align 32, offset 32] [from int]
+!19 = !{!20}
+!20 = !{!"0x21\000\002"} ; [ DW_TAG_subrange_type ] [0, 1]
+!21 = !{i32 2, !"Dwarf Version", i32 2}
+!22 = !{i32 1, !"Debug Info Version", i32 2}
+!23 = !{!"clang version 3.5.0 "}
+!24 = !{!"0x101\00outer\0016777226\000", !4, !5, !9} ; [ DW_TAG_arg_variable ] [ DW_TAG_arg_variable ] [outer] [line 10]
+!25 = !{i32 10, i32 0, !4, null}
+!26 = !{!"0x100\00i1\0011\000", !4, !5, !14} ; [ DW_TAG_auto_variable ] [ DW_TAG_auto_variable ] [i1] [line 11]
+!27 = !{i32 11, i32 0, !4, null}
+!28 = !{i32 12, i32 0, !4, null}
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