diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h index 88cefff50c3b5..ee7b2bb59050b 100644 --- a/llvm/include/llvm/IR/DebugInfoMetadata.h +++ b/llvm/include/llvm/IR/DebugInfoMetadata.h @@ -2464,6 +2464,10 @@ class DIExpression : public MDNode { /// Return whether this is an implicit location description. bool isImplicit() const; + /// Return whether the location is computed on the expression stack, meaning + /// it cannot be a simple register location. + bool isComplex() const; + /// Append \p Ops with operations to apply the \p Offset. static void appendOffset(SmallVectorImpl &Ops, int64_t Offset); diff --git a/llvm/lib/CodeGen/LiveDebugValues.cpp b/llvm/lib/CodeGen/LiveDebugValues.cpp index 5eb244080f14f..c01fc668f776f 100644 --- a/llvm/lib/CodeGen/LiveDebugValues.cpp +++ b/llvm/lib/CodeGen/LiveDebugValues.cpp @@ -642,9 +642,17 @@ void LiveDebugValues::insertTransferDebugPair( "No register supplied when handling a restore of a debug value"); MachineFunction *MF = MI.getMF(); DIBuilder DIB(*const_cast(MF->getFunction()).getParent()); + + const DIExpression *NewExpr; + if (auto Fragment = DebugInstr->getDebugExpression()->getFragmentInfo()) + NewExpr = *DIExpression::createFragmentExpression(DIB.createExpression(), + Fragment->OffsetInBits, Fragment->SizeInBits); + else + NewExpr = DIB.createExpression(); + NewDebugInstr = BuildMI(*MF, DebugInstr->getDebugLoc(), DebugInstr->getDesc(), false, - NewReg, DebugInstr->getDebugVariable(), DIB.createExpression()); + NewReg, DebugInstr->getDebugVariable(), NewExpr); VarLoc VL(*NewDebugInstr, LS); ProcessVarLoc(VL, NewDebugInstr); LLVM_DEBUG(dbgs() << "Creating DBG_VALUE inst for register restore: "; @@ -792,9 +800,14 @@ void LiveDebugValues::transferSpillOrRestoreInst(MachineInstr &MI, << "\n"); } // Check if the register or spill location is the location of a debug value. + // FIXME: Don't create a spill transfer if there is a complex expression, + // because we currently cannot recover the original expression on restore. for (unsigned ID : OpenRanges.getVarLocs()) { + const MachineInstr *DebugInstr = &VarLocIDs[ID].MI; + if (TKind == TransferKind::TransferSpill && - VarLocIDs[ID].isDescribedByReg() == Reg) { + VarLocIDs[ID].isDescribedByReg() == Reg && + !DebugInstr->getDebugExpression()->isComplex()) { LLVM_DEBUG(dbgs() << "Spilling Register " << printReg(Reg, TRI) << '(' << VarLocIDs[ID].Var.getVar()->getName() << ")\n"); } else if (TKind == TransferKind::TransferRestore && diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp index 94955678c25fd..811e638207cb1 100644 --- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp +++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp @@ -1187,6 +1187,16 @@ void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &MF, MI.getOperand(0).setIsDebug(); const DIExpression *DIExpr = MI.getDebugExpression(); + + // If we have a direct DBG_VALUE, and its location expression isn't + // currently complex, then adding an offset will morph it into a + // complex location that is interpreted as being a memory address. + // This changes a pointer-valued variable to dereference that pointer, + // which is incorrect. Fix by adding DW_OP_stack_value. + unsigned PrependFlags = DIExpression::ApplyOffset; + if (!MI.isIndirectDebugValue() && !DIExpr->isComplex()) + PrependFlags |= DIExpression::StackValue; + // If we have DBG_VALUE that is indirect and has a Implicit location // expression need to insert a deref before prepending a Memory // location expression. Also after doing this we change the DBG_VALUE @@ -1198,8 +1208,7 @@ void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &MF, // Make the DBG_VALUE direct. MI.getOperand(1).ChangeToRegister(0, false); } - DIExpr = - DIExpression::prepend(DIExpr, DIExpression::ApplyOffset, Offset); + DIExpr = DIExpression::prepend(DIExpr, PrependFlags, Offset); MI.getOperand(3).setMetadata(DIExpr); continue; } diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp index 76d9ce3332cf7..647bbcd999ee7 100644 --- a/llvm/lib/IR/DebugInfoMetadata.cpp +++ b/llvm/lib/IR/DebugInfoMetadata.cpp @@ -918,6 +918,27 @@ bool DIExpression::isImplicit() const { return false; } +bool DIExpression::isComplex() const { + if (!isValid()) + return false; + + if (getNumElements() == 0) + return false; + + // If there are any elements other than fragment or tag_offset, then some + // kind of complex computation occurs. + for (const auto &It : expr_ops()) { + switch (It.getOp()) { + case dwarf::DW_OP_LLVM_tag_offset: + case dwarf::DW_OP_LLVM_fragment: + continue; + default: return true; + } + } + + return false; +} + Optional DIExpression::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) { for (auto I = Start; I != End; ++I) diff --git a/llvm/test/DebugInfo/MIR/X86/live-debug-values-restore.mir b/llvm/test/DebugInfo/MIR/X86/live-debug-values-restore.mir index 2c3feeecdcdc8..f43572c7b654f 100644 --- a/llvm/test/DebugInfo/MIR/X86/live-debug-values-restore.mir +++ b/llvm/test/DebugInfo/MIR/X86/live-debug-values-restore.mir @@ -14,13 +14,17 @@ # return *(p + 1); # } +# Pick out DILocalVariable numbers for "p" and "q" +# CHECK: ![[PVAR:[0-9]+]] = !DILocalVariable(name: "p", +# CHECK: ![[QVAR:[0-9]+]] = !DILocalVariable(name: "q", + # Ascertain that the spill has been recognized and manifested in a DBG_VALUE. # CHECK: MOV64mr $rsp,{{.*-8.*}}killed{{.*}}$rdi :: (store 8 into %stack.0) -# CHECK-NEXT: DBG_VALUE $rsp,{{.*}}![[MDIX:[0-9]+]],{{.*}}!DIExpression(DW_OP_constu, 8, DW_OP_minus) +# CHECK-NEXT: DBG_VALUE $rsp,{{.*}}![[PVAR]],{{.*}}!DIExpression(DW_OP_constu, 8, DW_OP_minus) # Check for the restore. # CHECK: $rdi = MOV64rm $rsp,{{.*-8.*}}:: (load 8 from %stack.0) -# CHECK-NEXT: DBG_VALUE $rdi,{{.*}}![[MDIX]], !DIExpression() +# CHECK-NEXT: DBG_VALUE $rdi,{{.*}}![[PVAR]], !DIExpression() --- | define dso_local i32 @f(i32* readonly %p) local_unnamed_addr !dbg !7 { @@ -39,6 +43,22 @@ ret i32 %0, !dbg !28 } + define dso_local i32 @g(i32* readonly %p) local_unnamed_addr !dbg !107 { + entry: + call void @llvm.dbg.value(metadata i32* %p, metadata !113, metadata !DIExpression()), !dbg !114 + %tobool = icmp eq i32* %p, null, !dbg !115 + br i1 %tobool, label %if.end, label %if.then, !dbg !117 + + if.then: ; preds = %entry + tail call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rsi},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{dirflag},~{fpsr},~{flags}"(), !dbg !118, !srcloc !120 + br label %if.end, !dbg !121 + + if.end: ; preds = %entry, %if.then + %add.ptr = getelementptr inbounds i32, i32* %p, i64 1, !dbg !122 + %0 = load i32, i32* %add.ptr, align 4, !dbg !123, !tbaa !24 + ret i32 %0, !dbg !128 + } + declare void @llvm.dbg.value(metadata, metadata, metadata) !llvm.dbg.cu = !{!0} @@ -74,6 +94,22 @@ !26 = !{!"omnipotent char", !27, i64 0} !27 = !{!"Simple C/C++ TBAA"} !28 = !DILocation(line: 9, column: 3, scope: !7) + !101 = !DIBasicType(name: "looong int", size: 64, encoding: DW_ATE_signed) + !107 = distinct !DISubprogram(name: "g", scope: !1, file: !1, line: 105, type: !8, scopeLine: 105, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !112) + !112 = !{!113} + !113 = !DILocalVariable(name: "q", arg: 1, scope: !107, file: !1, line: 105, type: !101) + !114 = !DILocation(line: 105, column: 12, scope: !107) + !115 = !DILocation(line: 106, column: 7, scope: !116) + !116 = distinct !DILexicalBlock(scope: !107, file: !1, line: 106, column: 7) + !117 = !DILocation(line: 106, column: 7, scope: !107) + !118 = !DILocation(line: 107, column: 5, scope: !119) + !119 = distinct !DILexicalBlock(scope: !116, file: !1, line: 106, column: 10) + !120 = !{i32 -2147471544} + !121 = !DILocation(line: 108, column: 3, scope: !119) + !122 = !DILocation(line: 109, column: 14, scope: !107) + !123 = !DILocation(line: 109, column: 10, scope: !107) + !128 = !DILocation(line: 109, column: 3, scope: !107) + ... --- @@ -187,3 +223,78 @@ body: | RETQ $eax, debug-location !28 ... +--- +# This second function has been appended as a regression test against a +# crash, caused by expressions being created from spill restores that did +# not preserve fragment information. Test that no empty expressions are +# created at all, and the last block describes both variable fragments. + +# CHECK-LABEL: name: g +# CHECK-NOT: !DIExpression() +# CHECK-LABEL: bb.2.if.end: +# CHECK: DBG_VALUE $rdi, $noreg, ![[QVAR]], !DIExpression(DW_OP_LLVM_fragment, 0, 32) +# CHECK-NEXT: DBG_VALUE $rbx, $noreg, ![[QVAR]], !DIExpression(DW_OP_LLVM_fragment, 32, 32) + +name: g +alignment: 4 +tracksRegLiveness: true +liveins: + - { reg: '$rdi', virtual-reg: '' } +frameInfo: + stackSize: 48 + offsetAdjustment: -48 + maxAlignment: 8 + cvBytesOfCalleeSavedRegisters: 48 + localFrameSize: 0 +fixedStack: + - { id: 0, type: spill-slot, offset: -56, size: 8, alignment: 8, stack-id: default, + callee-saved-register: '$rbx', callee-saved-restored: true, debug-info-variable: '', + debug-info-expression: '', debug-info-location: '' } + - { id: 1, type: spill-slot, offset: -48, size: 8, alignment: 16, stack-id: default, + callee-saved-register: '$r12', callee-saved-restored: true, debug-info-variable: '', + debug-info-expression: '', debug-info-location: '' } + - { id: 2, type: spill-slot, offset: -40, size: 8, alignment: 8, stack-id: default, + callee-saved-register: '$r13', callee-saved-restored: true, debug-info-variable: '', + debug-info-expression: '', debug-info-location: '' } + - { id: 3, type: spill-slot, offset: -32, size: 8, alignment: 16, stack-id: default, + callee-saved-register: '$r14', callee-saved-restored: true, debug-info-variable: '', + debug-info-expression: '', debug-info-location: '' } + - { id: 4, type: spill-slot, offset: -24, size: 8, alignment: 8, stack-id: default, + callee-saved-register: '$r15', callee-saved-restored: true, debug-info-variable: '', + debug-info-expression: '', debug-info-location: '' } + - { id: 5, type: spill-slot, offset: -16, size: 8, alignment: 16, stack-id: default, + callee-saved-register: '$rbp', callee-saved-restored: true, debug-info-variable: '', + debug-info-expression: '', debug-info-location: '' } +stack: + - { id: 0, name: '', type: spill-slot, offset: -64, size: 8, alignment: 8, + stack-id: default, callee-saved-register: '', callee-saved-restored: true, + debug-info-variable: '', debug-info-expression: '', debug-info-location: '' } +constants: [] +body: | + bb.0.entry: + successors: %bb.1(0x50000000) + liveins: $rdi, $rbx, $r12, $r13, $r14, $r15, $rbp + + DBG_VALUE $rdi, $noreg, !113, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !114 + TEST64rr renamable $rdi, renamable $rdi, implicit-def $eflags, debug-location !115 + JMP_1 %bb.1, implicit $eflags, debug-location !117 + + bb.1.if.then: + successors: %bb.2(0x80000000) + liveins: $rdi, $rbp, $r15, $r14, $r13, $r12, $rbx + + MOV64mr $rsp, 1, $noreg, -8, $noreg, killed renamable $rdi :: (store 8 into %stack.0) + renamable $rdi = MOV64rm $rsp, 1, $noreg, -8, $noreg :: (load 8 from %stack.0) + + bb.2.if.end: + liveins: $rdi, $rbx, $r12, $r13, $r14, $r15, $rbp + + DBG_VALUE $rbx, $noreg, !113, !DIExpression(DW_OP_LLVM_fragment, 32, 32), debug-location !114 + MOV64mr $rsp, 1, $noreg, -8, $noreg, killed renamable $rbx :: (store 8 into %stack.0) + renamable $rsi = MOV64rm $rsp, 1, $noreg, -8, $noreg :: (load 8 from %stack.0) + + renamable $eax = MOV32rm killed renamable $rsi, 1, $noreg, 4, $noreg, debug-location !123 :: (load 4 from %ir.add.ptr, !tbaa !24) + $rdi = MOV64ri 0 + RETQ $eax, debug-location !128 + +... diff --git a/llvm/test/DebugInfo/MIR/X86/prolog-epilog-indirection.mir b/llvm/test/DebugInfo/MIR/X86/prolog-epilog-indirection.mir new file mode 100644 index 0000000000000..f86dd6b4ede36 --- /dev/null +++ b/llvm/test/DebugInfo/MIR/X86/prolog-epilog-indirection.mir @@ -0,0 +1,130 @@ +# RUN: llc %s -x mir -o - -mtriple=x86_64-unknown-unknown -run-pass=prologepilog | FileCheck %s +# +# Check when the DBG_VALUE on a stack slot below (for var "c") has its stack +# slot replaced with $rsp and a complex expression, it has DW_OP_stack_value +# added. A direct reference to the stack slot is considered to be the _address_ +# of that stack slot, wheras its contents would be an indirect DBG_VALUE. +# +# Check too that for the same DBG_VALUE inst, with an indirect reference to +# the stack slot, we do _not_ get DW_OP_plus_uconst added. This expression +# should remain indirect, referring to the contents of the stack slot. +# +# CHECK: ![[VAR:[0-9]+]] = !DILocalVariable(name: "c" +# CHECK: ![[VAR2:[0-9]+]] = !DILocalVariable(name: "asdf" +# CHECK: ![[VAR3:[0-9]+]] = !DILocalVariable(name: "bees" +# +# CHECK: LEA64r $rsp +# CHECK-NEXT: DBG_VALUE $rsp, $noreg, ![[VAR]], !DIExpression(DW_OP_plus_uconst, {{[0-9]+}}, DW_OP_stack_value) +# CHECK-NEXT: DBG_VALUE $rsp, $noreg, ![[VAR2]], !DIExpression(DW_OP_plus_uconst, {{[0-9]+}}, DW_OP_stack_value, DW_OP_LLVM_fragment, 1, 2) +# CHECK-NEXT: DBG_VALUE $rsp, $noreg, ![[VAR3]], !DIExpression(DW_OP_plus_uconst, {{[0-9]+}}, DW_OP_LLVM_tag_offset, 0, DW_OP_stack_value) +# CHECK-NEXT: DBG_VALUE 1834104526 +# CHECK-NEXT: MOV64mr +# CHECK-NEXT: DBG_VALUE $rsp, 0, ![[VAR]], !DIExpression(DW_OP_plus_uconst, {{[0-9]+}}) + +--- | + ; ModuleID = 'out.ll' + source_filename = "abc.c" + target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" + target triple = "x86_64-unknown-linux-gnu" + + @b = common dso_local local_unnamed_addr global i32* null, align 8, !dbg !0 + @a = common dso_local local_unnamed_addr global i32 0, align 4, !dbg !6 + + ; Function Attrs: nounwind uwtable + define dso_local i32 @main() local_unnamed_addr !dbg !14 { + entry: + %l_1081 = alloca i32, align 4 + %0 = bitcast i32* %l_1081 to i8*, !dbg !20 + call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %0), !dbg !20 + call void @llvm.dbg.value(metadata i32 1834104526, metadata !18, metadata !DIExpression()), !dbg !21 + call void @llvm.dbg.value(metadata i32* %l_1081, metadata !19, metadata !DIExpression()), !dbg !21 + store i32* %l_1081, i32** @b, align 8, !dbg !22, !tbaa !23 + store i32 9, i32* @a, align 4, !dbg !27, !tbaa !28 + store i32 9, i32* %l_1081, align 4, !dbg !30, !tbaa !28 + %call = call i32 (...) @optimize_me_not(), !dbg !31 + call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %0), !dbg !32 + ret i32 0, !dbg !32 + } + + ; Function Attrs: argmemonly nounwind + declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) + + declare dso_local i32 @optimize_me_not(...) local_unnamed_addr + + ; Function Attrs: argmemonly nounwind + declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) + + ; Function Attrs: nounwind readnone speculatable + declare void @llvm.dbg.value(metadata, metadata, metadata) + + !llvm.dbg.cu = !{!2} + !llvm.module.flags = !{!10, !11, !12} + !llvm.ident = !{!13} + + !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) + !1 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !3, line: 2, type: !9, isLocal: false, isDefinition: true) + !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None) + !3 = !DIFile(filename: "abc.c", directory: ".") + !4 = !{} + !5 = !{!6, !0} + !6 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression()) + !7 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true) + !8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) + !9 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !8, size: 64) + !10 = !{i32 2, !"Dwarf Version", i32 4} + !11 = !{i32 2, !"Debug Info Version", i32 3} + !12 = !{i32 1, !"wchar_size", i32 4} + !13 = !{!"clang"} + !14 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 3, type: !15, scopeLine: 3, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !17) + !15 = !DISubroutineType(types: !16) + !16 = !{!8} + !17 = !{!18, !19, !33, !34} + !18 = !DILocalVariable(name: "l_1081", scope: !14, file: !3, line: 4, type: !8) + !19 = !DILocalVariable(name: "c", scope: !14, file: !3, line: 5, type: !9) + !20 = !DILocation(line: 4, column: 3, scope: !14) + !21 = !DILocation(line: 0, scope: !14) + !22 = !DILocation(line: 6, column: 5, scope: !14) + !23 = !{!24, !24, i64 0} + !24 = !{!"any pointer", !25, i64 0} + !25 = !{!"omnipotent char", !26, i64 0} + !26 = !{!"Simple C/C++ TBAA"} + !27 = !DILocation(line: 7, column: 10, scope: !14) + !28 = !{!29, !29, i64 0} + !29 = !{!"int", !25, i64 0} + !30 = !DILocation(line: 7, column: 6, scope: !14) + !31 = !DILocation(line: 8, column: 3, scope: !14) + !32 = !DILocation(line: 9, column: 1, scope: !14) + !33 = !DILocalVariable(name: "asdf", scope: !14, file: !3, line: 4, type: !8) + !34 = !DILocalVariable(name: "bees", scope: !14, file: !3, line: 4, type: !8) + +... +--- +name: main +alignment: 4 +tracksRegLiveness: true +frameInfo: + maxAlignment: 4 + hasCalls: true +stack: + - { id: 0, name: l_1081, type: default, offset: 0, size: 4, alignment: 4, + callee-saved-register: '', callee-saved-restored: true, + debug-info-variable: '', debug-info-expression: '', debug-info-location: '' } +body: | + bb.0.entry: + renamable $rax = LEA64r %stack.0.l_1081, 1, $noreg, 0, $noreg + DBG_VALUE %stack.0.l_1081, $noreg, !19, !DIExpression(), debug-location !21 + DBG_VALUE %stack.0.l_1081, $noreg, !33, !DIExpression(DW_OP_LLVM_fragment, 1, 2), debug-location !21 + DBG_VALUE %stack.0.l_1081, $noreg, !34, !DIExpression(DW_OP_LLVM_tag_offset, 0), debug-location !21 + DBG_VALUE 1834104526, $noreg, !18, !DIExpression(), debug-location !21 + MOV64mr $rip, 1, $noreg, @b, $noreg, killed renamable $rax, debug-location !22 :: (store 8 into @b, !tbaa !23) + DBG_VALUE %stack.0.l_1081, 0, !19, !DIExpression(), debug-location !21 + MOV32mi $rip, 1, $noreg, @a, $noreg, 9, debug-location !27 :: (store 4 into @a, !tbaa !28) + MOV32mi %stack.0.l_1081, 1, $noreg, 0, $noreg, 9, debug-location !30 :: (store 4 into %ir.l_1081, !tbaa !28) + ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp, debug-location !31 + dead $eax = MOV32r0 implicit-def dead $eflags, implicit-def $al, debug-location !31 + CALL64pcrel32 @optimize_me_not, csr_64, implicit $rsp, implicit $ssp, implicit $al, implicit-def $rsp, implicit-def $ssp, implicit-def dead $eax, debug-location !31 + ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp, debug-location !31 + $eax = MOV32r0 implicit-def dead $eflags, debug-location !32 + RET 0, $eax, debug-location !32 + +...