[llvm] r278703 - Local variables whose address is taken and passed on to a call are described
Pieb, Wolfgang via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 19 10:48:56 PDT 2016
Hi Adrian,
No, I wasn't aware of this. By all means, if you have a test case, I'd be happy to address it.
-- wolfgang
> -----Original Message-----
> From: aprantl at apple.com [mailto:aprantl at apple.com]
> Sent: Friday, August 19, 2016 10:35 AM
> To: Pieb, Wolfgang
> Cc: LLVM Commits; Tim Northover
> Subject: Re: [llvm] r278703 - Local variables whose address is taken
> and passed on to a call are described
>
> Hello Wolfgang,
>
> one problem I came across with this change is that
> SelectionDAG::TransferDbgValues() currently doesn't handle FRAMEIX
> values at all which causes them to get dropped quite easily. I will try
> and come up with a testcase I can share, but in the meantime I was
> wondering if this is something you might already have patch in the
> pipeline for?
>
> -- adrian
>
> > On Aug 15, 2016, at 11:18 AM, Wolfgang Pieb via llvm-commits <llvm-
> commits at lists.llvm.org> wrote:
> >
> > Author: wolfgangp
> > Date: Mon Aug 15 13:18:26 2016
> > New Revision: 278703
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=278703&view=rev
> > Log:
> > Local variables whose address is taken and passed on to a call are
> > described in debug info using their stack slots instead of as an
> > indirection of param reg + 0 offset. This is done by detecting
> > FrameIndexSDNodes in SelectionDAG and generating FrameIndexDbgValues
> > for them. This ultimately generates DBG_VALUEs with stack location
> operands.
> >
> > Differential Revision: http://reviews.llvm.org/D23283
> >
> >
> > Added:
> > llvm/trunk/test/DebugInfo/X86/debug-loc-frame.ll
> > Modified:
> > llvm/trunk/include/llvm/IR/DebugInfoMetadata.h
> > llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> > llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
> > llvm/trunk/test/DebugInfo/AArch64/coalescing.ll
> > llvm/trunk/test/DebugInfo/X86/array.ll
> > llvm/trunk/test/DebugInfo/X86/bbjoin.ll
> > llvm/trunk/test/DebugInfo/X86/dbg-value-const-byref.ll
> >
> > Modified: llvm/trunk/include/llvm/IR/DebugInfoMetadata.h
> > URL:
> > http://llvm.org/viewvc/llvm-
> project/llvm/trunk/include/llvm/IR/DebugIn
> > foMetadata.h?rev=278703&r1=278702&r2=278703&view=diff
> >
> ======================================================================
> > ========
> > --- llvm/trunk/include/llvm/IR/DebugInfoMetadata.h (original)
> > +++ llvm/trunk/include/llvm/IR/DebugInfoMetadata.h Mon Aug 15
> 13:18:26
> > +++ 2016
> > @@ -2155,6 +2155,11 @@ public:
> > static bool classof(const Metadata *MD) {
> > return MD->getMetadataID() == DIExpressionKind;
> > }
> > +
> > + /// \brief Is the first element a DW_OP_deref?.
> > + bool startsWithDeref() const {
> > + return getNumElements() > 0 && getElement(0) ==
> > + dwarf::DW_OP_deref; }
> > };
> >
> > class DIObjCProperty : public DINode {
> >
> > Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> > URL:
> > http://llvm.org/viewvc/llvm-
> project/llvm/trunk/lib/CodeGen/SelectionDA
> > G/SelectionDAGBuilder.cpp?rev=278703&r1=278702&r2=278703&view=diff
> >
> ======================================================================
> > ========
> > --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> > (original)
> > +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Mon
> > +++ Aug 15 13:18:26 2016
> > @@ -1020,8 +1020,7 @@ void SelectionDAGBuilder::resolveDanglin
> > if (Val.getNode()) {
> > if (!EmitFuncArgumentDbgValue(V, Variable, Expr, dl, Offset,
> false,
> > Val)) {
> > - SDV = DAG.getDbgValue(Variable, Expr, Val.getNode(),
> Val.getResNo(),
> > - false, Offset, dl, DbgSDNodeOrder);
> > + SDV = getDbgValue(Val, Variable, Expr, Offset, dl,
> > + DbgSDNodeOrder);
> > DAG.AddDbgValue(SDV, Val.getNode(), false);
> > }
> > } else
> > @@ -4742,6 +4741,32 @@ bool SelectionDAGBuilder::EmitFuncArgume
> > return true;
> > }
> >
> > +/// Return the appropriate SDDbgValue based on N.
> > +SDDbgValue *SelectionDAGBuilder::getDbgValue(SDValue N,
> > + DILocalVariable
> *Variable,
> > + DIExpression *Expr,
> int64_t Offset,
> > + DebugLoc dl,
> > + unsigned
> DbgSDNodeOrder)
> > +{
> > + SDDbgValue *SDV;
> > + auto *FISDN = dyn_cast<FrameIndexSDNode>(N.getNode());
> > + if (FISDN && Expr->startsWithDeref()) {
> > + // Construct a FrameIndexDbgValue for FrameIndexSDNodes so we
> can describe
> > + // stack slot locations as such instead of as indirectly
> addressed
> > + // locations.
> > + ArrayRef<uint64_t> TrailingElements(Expr->elements_begin() + 1,
> > + Expr->elements_end());
> > + DIExpression *DerefedDIExpr =
> > + DIExpression::get(*DAG.getContext(), TrailingElements);
> > + int FI = FISDN->getIndex();
> > + SDV = DAG.getFrameIndexDbgValue(Variable, DerefedDIExpr, FI, 0,
> dl,
> > + DbgSDNodeOrder);
> > + } else {
> > + SDV = DAG.getDbgValue(Variable, Expr, N.getNode(), N.getResNo(),
> false,
> > + Offset, dl, DbgSDNodeOrder);
> > + }
> > + return SDV;
> > +}
> > +
> > // VisualStudio defines setjmp as _setjmp #if defined(_MSC_VER) &&
> > defined(setjmp) && \
> > !defined(setjmp_undefined_for_msvc)
> > @@ -4943,8 +4968,7 @@ SelectionDAGBuilder::visitIntrinsicCall(
> > if (N.getNode()) {
> > if (!EmitFuncArgumentDbgValue(V, Variable, Expression, dl,
> Offset,
> > false, N)) {
> > - SDV = DAG.getDbgValue(Variable, Expression, N.getNode(),
> N.getResNo(),
> > - false, Offset, dl, SDNodeOrder);
> > + SDV = getDbgValue(N, Variable, Expression, Offset, dl,
> > + SDNodeOrder);
> > DAG.AddDbgValue(SDV, N.getNode(), false);
> > }
> > } else if (!V->use_empty() ) {
> >
> > Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
> > URL:
> > http://llvm.org/viewvc/llvm-
> project/llvm/trunk/lib/CodeGen/SelectionDA
> > G/SelectionDAGBuilder.h?rev=278703&r1=278702&r2=278703&view=diff
> >
> ======================================================================
> > ========
> > --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
> > (original)
> > +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h Mon Aug
> > +++ 15 13:18:26 2016
> > @@ -942,6 +942,11 @@ private:
> > /// Update the DAG and DAG builder with the relevant information
> after
> > /// a new root node has been created which could be a tail call.
> > void updateDAGForMaybeTailCall(SDValue MaybeTC);
> > +
> > + /// Return the appropriate SDDbgValue based on N.
> > + SDDbgValue *getDbgValue(SDValue N, DILocalVariable *Variable,
> > + DIExpression *Expr, int64_t Offset,
> DebugLoc dl,
> > + unsigned DbgSDNodeOrder);
> > };
> >
> > /// RegsForValue - This struct represents the registers (physical or
> > virtual)
> >
> > Modified: llvm/trunk/test/DebugInfo/AArch64/coalescing.ll
> > URL:
> > http://llvm.org/viewvc/llvm-
> project/llvm/trunk/test/DebugInfo/AArch64/
> > coalescing.ll?rev=278703&r1=278702&r2=278703&view=diff
> >
> ======================================================================
> > ========
> > --- llvm/trunk/test/DebugInfo/AArch64/coalescing.ll (original)
> > +++ llvm/trunk/test/DebugInfo/AArch64/coalescing.ll Mon Aug 15
> > +++ 13:18:26 2016
> > @@ -25,7 +25,8 @@ entry:
> > ; CHECK-NEXT: DW_AT_location
> > ; CHECK-NEXT: DW_AT_name {{.*}}"size"
> > ; CHECK: .debug_loc contents:
> > - ; CHECK: Location description: 70 00
> > + ; Expecting the encoding for sp+12: DW_OP_breg31 0c ; CHECK:
> > + Location description: 8f 0c
> > ret void, !dbg !18
> > }
> >
> >
> > Modified: llvm/trunk/test/DebugInfo/X86/array.ll
> > URL:
> > http://llvm.org/viewvc/llvm-
> project/llvm/trunk/test/DebugInfo/X86/arra
> > y.ll?rev=278703&r1=278702&r2=278703&view=diff
> >
> ======================================================================
> > ========
> > --- llvm/trunk/test/DebugInfo/X86/array.ll (original)
> > +++ llvm/trunk/test/DebugInfo/X86/array.ll Mon Aug 15 13:18:26 2016
> > @@ -16,9 +16,7 @@
> > ; Test that we only emit register-indirect locations for the array
> array.
> > ; rdar://problem/14874886
> > ;
> > -; FIXME: If we described this location as RSP-relative instead of
> > RDI-relative -; the live range would be larger.
> > -; CHECK: ##DEBUG_VALUE: main:array <- [%RDI+0]
> > +; CHECK: ##DEBUG_VALUE: main:array <- [%RSP+0]
> > ; CHECK-NOT: ##DEBUG_VALUE: main:array <- %R{{.*}} target datalayout
> =
> > "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
> > target triple = "x86_64-apple-macosx10.9.0"
> >
> > Modified: llvm/trunk/test/DebugInfo/X86/bbjoin.ll
> > URL:
> > http://llvm.org/viewvc/llvm-
> project/llvm/trunk/test/DebugInfo/X86/bbjo
> > in.ll?rev=278703&r1=278702&r2=278703&view=diff
> >
> ======================================================================
> > ========
> > --- llvm/trunk/test/DebugInfo/X86/bbjoin.ll (original)
> > +++ llvm/trunk/test/DebugInfo/X86/bbjoin.ll Mon Aug 15 13:18:26 2016
> > @@ -12,7 +12,7 @@
> > ; CHECK: ![[X:.*]] = !DILocalVariable(name: "x", ; CHECK: bb.0.entry:
> > ; CHECK: DBG_VALUE 23, 0, ![[X]],
> > -; CHECK: DBG_VALUE debug-use %rdi, debug-use _, ![[X]]
> > +; CHECK: DBG_VALUE %rsp, 4, ![[X]]
> > ; CHECK: bb.1.if.then:
> > ; CHECK: DBG_VALUE 43, 0, ![[X]],
> > ; CHECK: bb.2.if.end:
> >
> > Modified: llvm/trunk/test/DebugInfo/X86/dbg-value-const-byref.ll
> > URL:
> > http://llvm.org/viewvc/llvm-
> project/llvm/trunk/test/DebugInfo/X86/dbg-
> > value-const-byref.ll?rev=278703&r1=278702&r2=278703&view=diff
> >
> ======================================================================
> > ========
> > --- llvm/trunk/test/DebugInfo/X86/dbg-value-const-byref.ll (original)
> > +++ llvm/trunk/test/DebugInfo/X86/dbg-value-const-byref.ll Mon Aug 15
> > +++ 13:18:26 2016
> > @@ -41,7 +41,8 @@
> > ; rdi+0
> > ; CHECK: Beginning address offset: [[R1]]
> > ; CHECK: Ending address offset: [[R2:.*]]
> > -; CHECK: Location description: 75 00
> > +; CHECK: Location description: 77 04
> > +; rsp+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/debug-loc-frame.ll
> > URL:
> > http://llvm.org/viewvc/llvm-
> project/llvm/trunk/test/DebugInfo/X86/debu
> > g-loc-frame.ll?rev=278703&view=auto
> >
> ======================================================================
> > ========
> > --- llvm/trunk/test/DebugInfo/X86/debug-loc-frame.ll (added)
> > +++ llvm/trunk/test/DebugInfo/X86/debug-loc-frame.ll Mon Aug 15
> > +++ 13:18:26 2016
> > @@ -0,0 +1,113 @@
> > +; REQUIRES: object-emission
> > +
> > +; Check that when variables are allocated on the stack we generate
> > +debug locations ; for the stack location directly instead of
> generating a register+offset indirection.
> > +
> > +; RUN: %llc_dwarf -O2 -filetype=obj -disable-post-ra < %s |
> > +llvm-dwarfdump - | FileCheck %s ; ; int data = 17; ; int sum = 0; ;
> > +int zero = 0; ; int *ptr; ; ; extern void foo(int i, int *p); ; ;
> int
> > +main() ; {
> > +; int val;
> > +; val = data;
> > +; foo(1, &val);
> > +; foo(2, &data);
> > +; return zero;
> > +; }
> > +;
> > +; CHECK: .debug_info contents
> > +; CHECK: DW_TAG_subprogram
> > +; CHECK-NOT: NULL
> > +; CHECK: DW_TAG_variable
> > +; CHECK: DW_AT_location [DW_FORM_sec_offset]
> ([[DEBUGLOCOFFSET:0x[0-9a-f]+]]){{[[:space:]].*}}"val"
> > +
> > +; See that 'val' has at least one location entry with a DW_op_breg?
> operand.
> > +; The DWARF DW_op_breg* ops are encoded from 0x70 to 0x8f, but
> > +checking for an ; op in the range from 0x70 to 0x7f should suffice
> > +because that range covers ; all integer GPRs.
> > +;
> > +; CHECK: .debug_loc contents:
> > +; CHECK-NOT: .debug{{.*}} contents
> > +; CHECK: [[DEBUGLOCOFFSET]]: Beginning ; CHECK-NOT: {{0x[0-9a-f]+}}:
> > +Beginning ; CHECK: Location description: 7{{[0-9a-f] .*}}
> > +
> > +; ModuleID = 'frame.c'
> > +source_filename = "frame.c"
> > +
> > + at data = global i32 17, align 4
> > + at sum = local_unnamed_addr global i32 0, align 4 @zero =
> > +local_unnamed_addr global i32 0, align 4 @ptr = common
> > +local_unnamed_addr global i32* null, align 8
> > +
> > +; Function Attrs: nounwind uwtable
> > +define i32 @main() local_unnamed_addr !dbg !13 {
> > +entry:
> > + %val = alloca i32, align 4
> > + %0 = bitcast i32* %val to i8*, !dbg !18
> > + call void @llvm.lifetime.start(i64 4, i8* %0), !dbg !18
> > + %1 = load i32, i32* @data, align 4, !dbg !19, !tbaa !20
> > + tail call void @llvm.dbg.value(metadata i32 %1, i64 0, metadata
> > +!17, metadata !24), !dbg !25
> > + store i32 %1, i32* %val, align 4, !dbg !26, !tbaa !20
> > + tail call void @llvm.dbg.value(metadata i32* %val, i64 0, metadata
> > +!17, metadata !27), !dbg !25
> > + call void @foo(i32 1, i32* nonnull %val), !dbg !28
> > + call void @foo(i32 2, i32* nonnull @data), !dbg !29
> > + %2 = load i32, i32* @zero, align 4, !dbg !30, !tbaa !20
> > + call void @llvm.lifetime.end(i64 4, i8* %0), !dbg !31
> > + ret i32 %2, !dbg !32
> > +}
> > +
> > +; Function Attrs: argmemonly nounwind declare void
> > + at llvm.lifetime.start(i64, i8* nocapture)
> > +
> > +declare void @foo(i32, i32*) local_unnamed_addr
> > +
> > +; Function Attrs: argmemonly nounwind declare void
> > + at llvm.lifetime.end(i64, i8* nocapture)
> > +
> > +; Function Attrs: nounwind readnone
> > +declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
> > +
> > +!llvm.dbg.cu = !{!0}
> > +!llvm.module.flags = !{!10, !11}
> > +!llvm.ident = !{!12}
> > +
> > +!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1,
> > +producer: "clang version 3.9.0 (trunk 273961)", isOptimized: true,
> > +runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3)
> > +!1 = !DIFile(filename: "frame.c", directory: "/home/user/test")
> > +!2 = !{}
> > +!3 = !{!4, !6, !7, !8}
> > +!4 = distinct !DIGlobalVariable(name: "data", scope: !0, file: !1,
> > +line: 1, type: !5, isLocal: false, isDefinition: true, variable:
> i32*
> > + at data)
> > +!5 = !DIBasicType(name: "int", size: 32, align: 32, encoding:
> > +DW_ATE_signed)
> > +!6 = distinct !DIGlobalVariable(name: "sum", scope: !0, file: !1,
> > +line: 2, type: !5, isLocal: false, isDefinition: true, variable:
> i32*
> > + at sum)
> > +!7 = distinct !DIGlobalVariable(name: "zero", scope: !0, file: !1,
> > +line: 3, type: !5, isLocal: false, isDefinition: true, variable:
> i32*
> > + at zero)
> > +!8 = distinct !DIGlobalVariable(name: "ptr", scope: !0, file: !1,
> > +line: 4, type: !9, isLocal: false, isDefinition: true, variable:
> > +i32** @ptr)
> > +!9 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !5, size:
> 64,
> > +align: 64)
> > +!10 = !{i32 2, !"Dwarf Version", i32 4}
> > +!11 = !{i32 2, !"Debug Info Version", i32 3}
> > +!12 = !{!"clang version 3.9.0 (trunk 273961)"}
> > +!13 = distinct !DISubprogram(name: "main", scope: !1, file: !1,
> line:
> > +8, type: !14, isLocal: false, isDefinition: true, scopeLine: 9,
> > +isOptimized: true, unit: !0, variables: !16)
> > +!14 = !DISubroutineType(types: !15)
> > +!15 = !{!5}
> > +!16 = !{!17}
> > +!17 = !DILocalVariable(name: "val", scope: !13, file: !1, line: 10,
> > +type: !5)
> > +!18 = !DILocation(line: 10, column: 3, scope: !13)
> > +!19 = !DILocation(line: 11, column: 9, scope: !13)
> > +!20 = !{!21, !21, i64 0}
> > +!21 = !{!"int", !22, i64 0}
> > +!22 = !{!"omnipotent char", !23, i64 0}
> > +!23 = !{!"Simple C/C++ TBAA"}
> > +!24 = !DIExpression()
> > +!25 = !DILocation(line: 10, column: 7, scope: !13)
> > +!26 = !DILocation(line: 11, column: 7, scope: !13)
> > +!27 = !DIExpression(DW_OP_deref)
> > +!28 = !DILocation(line: 12, column: 3, scope: !13)
> > +!29 = !DILocation(line: 13, column: 3, scope: !13)
> > +!30 = !DILocation(line: 14, column: 10, scope: !13)
> > +!31 = !DILocation(line: 15, column: 1, scope: !13)
> > +!32 = !DILocation(line: 14, column: 3, scope: !13)
> >
> >
> > _______________________________________________
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