diff options
author | Stephen Tozer <Stephen.Tozer@Sony.com> | 2023-09-06 19:18:37 +0100 |
---|---|---|
committer | Stephen Tozer <Stephen.Tozer@Sony.com> | 2023-09-15 19:07:44 +0100 |
commit | 9811ffe7d0fcf3b452e06cb4db1e998979b3093d (patch) | |
tree | c3611bebbce30572de559012b7f9645be054732d | |
parent | 32db121b29f78e4c41116b2a8f1c730f9522b202 (diff) | |
download | llvm-9811ffe7d0fcf3b452e06cb4db1e998979b3093d.zip llvm-9811ffe7d0fcf3b452e06cb4db1e998979b3093d.tar.gz llvm-9811ffe7d0fcf3b452e06cb4db1e998979b3093d.tar.bz2 |
[DebugInfo] Process single-location debug values in variadic form when producing DWARF
Revision c383f4d6550e enabled using variadic-form debug values to represent
single-location, non-stack-value debug values, and a further patch made all
DBG_INSTR_REFs use variadic form. Not all code paths were updated correctly to
handle the new syntax however, with entry values in still expecting an expression
that begins exactly DW_OP_LLVM_entry_value, 1.
A function already exists to select non-variadic-like expressions; this patch
adds an extra function to cheaply simplify such cases to non-variadic form, which
we use prior to any entry-value processing to put DBG_INSTR_REFs and DBG_VALUEs
down the same code path. We also use it for a few DIExpression functions that
check for whether the first element(s) of a DIExpression match a particular
pattern, so that they will return the same result for
DIExpression(DW_OP_LLVM_arg, 0, <ops>) as for DIExpression(<ops>).
Differential Revision: https://reviews.llvm.org/D158185
-rw-r--r-- | llvm/include/llvm/IR/DebugInfoMetadata.h | 10 | ||||
-rw-r--r-- | llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 10 | ||||
-rw-r--r-- | llvm/lib/IR/DebugInfoMetadata.cpp | 101 | ||||
-rw-r--r-- | llvm/test/DebugInfo/X86/debug-value-list-entry-value.mir | 82 | ||||
-rw-r--r-- | llvm/test/DebugInfo/X86/pr52584.ll | 2 |
5 files changed, 168 insertions, 37 deletions
diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h index 9beb514..b347664 100644 --- a/llvm/include/llvm/IR/DebugInfoMetadata.h +++ b/llvm/include/llvm/IR/DebugInfoMetadata.h @@ -2850,6 +2850,13 @@ public: /// DW_OP_LLVM_arg op as its first operand, or if it contains none. bool isSingleLocationExpression() const; + /// Returns a reference to the elements contained in this expression, skipping + /// past the leading `DW_OP_LLVM_arg, 0` if one is present. + /// Similar to `convertToNonVariadicExpression`, but faster and cheaper - it + /// does not check whether the expression is a single-location expression, and + /// it returns elements rather than creating a new DIExpression. + std::optional<ArrayRef<uint64_t>> getSingleLocationExpressionElements() const; + /// Removes all elements from \p Expr that do not apply to an undef debug /// value, which includes every operator that computes the value/location on /// the DWARF stack, including any DW_OP_LLVM_arg elements (making the result @@ -2868,6 +2875,9 @@ public: /// single debug operand at the start of the expression, then return that /// expression in a non-variadic form by removing DW_OP_LLVM_arg from the /// expression if it is present; otherwise returns std::nullopt. + /// See also `getSingleLocationExpressionElements` above, which skips + /// checking `isSingleLocationExpression` and returns a list of elements + /// rather than a DIExpression. static std::optional<const DIExpression *> convertToNonVariadicExpression(const DIExpression *Expr); diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index 1cb65a8..05fb219c 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -234,7 +234,15 @@ const DIType *DbgVariable::getType() const { /// Get .debug_loc entry for the instruction range starting at MI. static DbgValueLoc getDebugLocValue(const MachineInstr *MI) { const DIExpression *Expr = MI->getDebugExpression(); - const bool IsVariadic = MI->isDebugValueList(); + auto SingleLocExprOpt = DIExpression::convertToNonVariadicExpression(Expr); + const bool IsVariadic = !SingleLocExprOpt; + // If we have a variadic debug value instruction that is equivalent to a + // non-variadic instruction, then convert it to non-variadic form here. + if (!IsVariadic && !MI->isNonListDebugValue()) { + assert(MI->getNumDebugOperands() == 1 && + "Mismatched DIExpression and debug operands for debug instruction."); + Expr = *SingleLocExprOpt; + } assert(MI->getNumOperands() >= 3); SmallVector<DbgValueLocEntry, 4> DbgValueLocEntries; for (const MachineOperand &Op : MI->debug_operands()) { diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp index 4933b603..f7f3612 100644 --- a/llvm/lib/IR/DebugInfoMetadata.cpp +++ b/llvm/lib/IR/DebugInfoMetadata.cpp @@ -1345,13 +1345,23 @@ DIExpression *DIExpression::getImpl(LLVMContext &Context, DEFINE_GETIMPL_STORE_NO_OPS(DIExpression, (Elements)); } bool DIExpression::isEntryValue() const { - return getNumElements() > 0 && getElement(0) == dwarf::DW_OP_LLVM_entry_value; + if (auto singleLocElts = getSingleLocationExpressionElements()) { + return singleLocElts->size() > 0 && + (*singleLocElts)[0] == dwarf::DW_OP_LLVM_entry_value; + } + return false; } bool DIExpression::startsWithDeref() const { - return getNumElements() > 0 && getElement(0) == dwarf::DW_OP_deref; + if (auto singleLocElts = getSingleLocationExpressionElements()) + return singleLocElts->size() > 0 && + (*singleLocElts)[0] == dwarf::DW_OP_deref; + return false; } bool DIExpression::isDeref() const { - return getNumElements() == 1 && startsWithDeref(); + if (auto singleLocElts = getSingleLocationExpressionElements()) + return singleLocElts->size() == 1 && + (*singleLocElts)[0] == dwarf::DW_OP_deref; + return false; } DIAssignID *DIAssignID::getImpl(LLVMContext &Context, StorageType Storage, @@ -1528,14 +1538,34 @@ bool DIExpression::isSingleLocationExpression() const { auto ExprOpBegin = expr_ops().begin(); auto ExprOpEnd = expr_ops().end(); - if (ExprOpBegin->getOp() == dwarf::DW_OP_LLVM_arg) + if (ExprOpBegin->getOp() == dwarf::DW_OP_LLVM_arg) { + if (ExprOpBegin->getArg(0) != 0) + return false; ++ExprOpBegin; + } return !std::any_of(ExprOpBegin, ExprOpEnd, [](auto Op) { return Op.getOp() == dwarf::DW_OP_LLVM_arg; }); } +std::optional<ArrayRef<uint64_t>> +DIExpression::getSingleLocationExpressionElements() const { + // Check for `isValid` covered by `isSingleLocationExpression`. + if (!isSingleLocationExpression()) + return std::nullopt; + + // An empty expression is already non-variadic. + if (!getNumElements()) + return ArrayRef<uint64_t>(); + + // If Expr does not have a leading DW_OP_LLVM_arg then we don't need to do + // anything. + if (getElements()[0] == dwarf::DW_OP_LLVM_arg) + return getElements().drop_front(2); + return getElements(); +} + const DIExpression * DIExpression::convertToUndefExpression(const DIExpression *Expr) { SmallVector<uint64_t, 3> UndefOps; @@ -1561,23 +1591,13 @@ DIExpression::convertToVariadicExpression(const DIExpression *Expr) { std::optional<const DIExpression *> DIExpression::convertToNonVariadicExpression(const DIExpression *Expr) { - // Check for `isValid` covered by `isSingleLocationExpression`. - if (!Expr->isSingleLocationExpression()) + if (!Expr) return std::nullopt; - // An empty expression is already non-variadic. - if (!Expr->getNumElements()) - return Expr; + if (auto Elts = Expr->getSingleLocationExpressionElements()) + return DIExpression::get(Expr->getContext(), *Elts); - auto ElementsBegin = Expr->elements_begin(); - // If Expr does not have a leading DW_OP_LLVM_arg then we don't need to do - // anything. - if (*ElementsBegin != dwarf::DW_OP_LLVM_arg) - return Expr; - - SmallVector<uint64_t> NonVariadicOps( - make_range(ElementsBegin + 2, Expr->elements_end())); - return DIExpression::get(Expr->getContext(), NonVariadicOps); + return std::nullopt; } void DIExpression::canonicalizeExpressionOps(SmallVectorImpl<uint64_t> &Ops, @@ -1648,23 +1668,29 @@ void DIExpression::appendOffset(SmallVectorImpl<uint64_t> &Ops, } bool DIExpression::extractIfOffset(int64_t &Offset) const { - if (getNumElements() == 0) { + auto SingleLocEltsOpt = getSingleLocationExpressionElements(); + if (!SingleLocEltsOpt) + return false; + auto SingleLocElts = *SingleLocEltsOpt; + + if (SingleLocElts.size() == 0) { Offset = 0; return true; } - if (getNumElements() == 2 && Elements[0] == dwarf::DW_OP_plus_uconst) { - Offset = Elements[1]; + if (SingleLocElts.size() == 2 && + SingleLocElts[0] == dwarf::DW_OP_plus_uconst) { + Offset = SingleLocElts[1]; return true; } - if (getNumElements() == 3 && Elements[0] == dwarf::DW_OP_constu) { - if (Elements[2] == dwarf::DW_OP_plus) { - Offset = Elements[1]; + if (SingleLocElts.size() == 3 && SingleLocElts[0] == dwarf::DW_OP_constu) { + if (SingleLocElts[2] == dwarf::DW_OP_plus) { + Offset = SingleLocElts[1]; return true; } - if (Elements[2] == dwarf::DW_OP_minus) { - Offset = -Elements[1]; + if (SingleLocElts[2] == dwarf::DW_OP_minus) { + Offset = -SingleLocElts[1]; return true; } } @@ -1687,18 +1713,23 @@ const DIExpression *DIExpression::extractAddressClass(const DIExpression *Expr, unsigned &AddrClass) { // FIXME: This seems fragile. Nothing that verifies that these elements // actually map to ops and not operands. + auto SingleLocEltsOpt = Expr->getSingleLocationExpressionElements(); + if (!SingleLocEltsOpt) + return nullptr; + auto SingleLocElts = *SingleLocEltsOpt; + const unsigned PatternSize = 4; - if (Expr->Elements.size() >= PatternSize && - Expr->Elements[PatternSize - 4] == dwarf::DW_OP_constu && - Expr->Elements[PatternSize - 2] == dwarf::DW_OP_swap && - Expr->Elements[PatternSize - 1] == dwarf::DW_OP_xderef) { - AddrClass = Expr->Elements[PatternSize - 3]; + if (SingleLocElts.size() >= PatternSize && + SingleLocElts[PatternSize - 4] == dwarf::DW_OP_constu && + SingleLocElts[PatternSize - 2] == dwarf::DW_OP_swap && + SingleLocElts[PatternSize - 1] == dwarf::DW_OP_xderef) { + AddrClass = SingleLocElts[PatternSize - 3]; - if (Expr->Elements.size() == PatternSize) + if (SingleLocElts.size() == PatternSize) return nullptr; - return DIExpression::get(Expr->getContext(), - ArrayRef(&*Expr->Elements.begin(), - Expr->Elements.size() - PatternSize)); + return DIExpression::get( + Expr->getContext(), + ArrayRef(&*SingleLocElts.begin(), SingleLocElts.size() - PatternSize)); } return Expr; } diff --git a/llvm/test/DebugInfo/X86/debug-value-list-entry-value.mir b/llvm/test/DebugInfo/X86/debug-value-list-entry-value.mir new file mode 100644 index 0000000..06a72c6 --- /dev/null +++ b/llvm/test/DebugInfo/X86/debug-value-list-entry-value.mir @@ -0,0 +1,82 @@ +# RUN: llc %s --start-after=livedebugvalues --filetype=obj -o - \ +# RUN: | llvm-dwarfdump - --name=test-var -o - | FileCheck %s + +# Test that when an entry value expression appears in a DBG_VALUE_LIST, we are +# able to produce a valid entry value location in DWARF. + +# CHECK: DW_OP_entry_value(DW_OP_reg14 R14), DW_OP_plus_uconst 0x10, DW_OP_plus_uconst 0x10, DW_OP_deref + +--- | + source_filename = "test.ll" + target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" + target triple = "x86_64-apple-macosx12.1.0" + + declare void @llvm.dbg.value(metadata, metadata, metadata) + + define swifttailcc void @blah(ptr swiftasync %0) !dbg !15 { + %use = getelementptr i8, ptr %0, i64 9 + call void @llvm.dbg.value(metadata ptr %0, metadata !18, metadata !DIExpression(DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 16, DW_OP_deref, DW_OP_deref)), !dbg !22 + %use1 = load i32, ptr null, align 4, !dbg !27 + %use2 = sext i32 %use1 to i64 + %use3 = getelementptr i8, ptr null, i64 %use2 + store ptr %use3, ptr %0, align 8 + ret void + } + + !llvm.module.flags = !{!0} + !llvm.dbg.cu = !{!1} + + !0 = !{i32 2, !"Debug Info Version", i32 3} + !1 = distinct !DICompileUnit(language: DW_LANG_Swift, file: !2, producer: "blah", isOptimized: true, flags: "blah", runtimeVersion: 5, emissionKind: FullDebug, globals: !3, imports: !9, sysroot: "blah", sdk: "blah") + !2 = !DIFile(filename: "blah", directory: "blah") + !3 = !{!4, !10} + !4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression()) + !5 = distinct !DIGlobalVariable(name: "blah", linkageName: "blah", scope: !6, file: !2, line: 49, type: !7, isLocal: true, isDefinition: true) + !6 = !DIModule(scope: null, name: "blah", includePath: "blah") + !7 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !8) + !8 = !DICompositeType(tag: DW_TAG_structure_type, name: "blah", scope: !6, file: !2, size: 64, elements: !9, runtimeLang: DW_LANG_Swift, identifier: "blah") + !9 = !{} + !10 = !DIGlobalVariableExpression(var: !11, expr: !DIExpression()) + !11 = distinct !DIGlobalVariable(name: "blah", linkageName: "blah", scope: !6, file: !2, line: 44, type: !12, isLocal: false, isDefinition: true) + !12 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !13) + !13 = !DICompositeType(tag: DW_TAG_structure_type, name: "blah", scope: !14, file: !2, size: 64, elements: !9, runtimeLang: DW_LANG_Swift, identifier: "blah") + !14 = !DIModule(scope: null, name: "blah", configMacros: "blah", includePath: "blah") + !15 = distinct !DISubprogram(name: "blah", linkageName: "blah", scope: !16, file: !2, line: 115, type: !17, scopeLine: 117, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !1, retainedNodes: !9, thrownTypes: !9) + !16 = !DICompositeType(tag: DW_TAG_structure_type, name: "blah", scope: !6, file: !2, elements: !9, runtimeLang: DW_LANG_Swift, identifier: "blah") + !17 = !DISubroutineType(types: !9) + !18 = !DILocalVariable(name: "test-var", arg: 1, scope: !19, file: !2, line: 95, type: !21, flags: DIFlagArtificial) + !19 = distinct !DISubprogram(name: "blah", linkageName: "blah", scope: !16, file: !2, line: 95, type: !20, scopeLine: 95, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !1, retainedNodes: !9) + !20 = distinct !DISubroutineType(types: !9) + !21 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !16) + !22 = !DILocation(line: 95, column: 9, scope: !19, inlinedAt: !23) + !23 = distinct !DILocation(line: 0, scope: !24, inlinedAt: !25) + !24 = distinct !DISubprogram(name: "blah", linkageName: "blah", scope: !16, file: !2, type: !20, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !1) + !25 = distinct !DILocation(line: 121, column: 36, scope: !26) + !26 = distinct !DILexicalBlock(scope: !15, file: !2, line: 116, column: 7) + !27 = !DILocation(line: 0, scope: !28, inlinedAt: !23) + !28 = !DILexicalBlockFile(scope: !19, file: !2, discriminator: 0) + +... +--- +name: blah +alignment: 16 +tracksRegLiveness: true +debugInstrRef: true +tracksDebugUserValues: true +registers: [] +liveins: + - { reg: '$r14', virtual-reg: '' } +frameInfo: + maxAlignment: 1 +body: | + bb.0 (%ir-block.1): + liveins: $r14 + + DBG_PHI $r14, 1 + DBG_INSTR_REF !18, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 16, DW_OP_deref, DW_OP_deref), dbg-instr-ref(1, 0), debug-location !22 + DBG_VALUE_LIST !18, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 16, DW_OP_deref, DW_OP_deref), $r14, debug-location !DILocation(line: 0, scope: !19, inlinedAt: !23) + renamable $rax = MOVSX64rm32 $noreg, 1, $noreg, 0, $noreg, debug-location !27 :: (load (s32) from `ptr null`) + MOV64mr killed renamable $r14, 1, $noreg, 0, $noreg, killed renamable $rax :: (store (s64) into %ir.0) + RETI64 8 + +... diff --git a/llvm/test/DebugInfo/X86/pr52584.ll b/llvm/test/DebugInfo/X86/pr52584.ll index 5ceb0d82..a08a40a7 100644 --- a/llvm/test/DebugInfo/X86/pr52584.ll +++ b/llvm/test/DebugInfo/X86/pr52584.ll @@ -9,7 +9,7 @@ ; CHECK: DW_TAG define dso_local void @test() !dbg !4 { entry: - call void @llvm.dbg.value(metadata !DIArgList(i128 0), metadata !7, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 127)), !dbg !12 + call void @llvm.dbg.value(metadata !DIArgList(i128 0), metadata !7, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 0, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 127)), !dbg !12 ret void, !dbg !12 } |