From 889dad7f40932ea68c9e287e62441507f4f0f261 Mon Sep 17 00:00:00 2001 From: Michael Buch Date: Thu, 17 Apr 2025 21:53:32 +0100 Subject: [ItaniumDemangle] Add customizable printLeft/printRight APIs to OutputBuffer (#133249) This patch includes the necessary changes for the LLDB feature proposed in https://discourse.llvm.org/t/rfc-lldb-highlighting-function-names-in-lldb-backtraces/85309. The TL;DR is that we want to track where certain parts of a demangled name begin/end so we can highlight them in backtraces. We introduce a new `printLeft`/`printRight` API on `OutputBuffer` that a client (in our case LLDB) can implement to track state while printing the demangle tree. This requires redirecting all calls to to `printLeft`/`printRight` to the `OutputBuffer`. One quirk with the new API is that `Utility.h` would now depend on `ItaniumDemangle.h` and vice-versa. To keep these files header-only I made the definitions `inline` and implement the new APIs in `ItaniumDemangle.h` (so the definition of `Node` is available to them). Also introduces `notifyInsertion`/`notifyDeletion` APIs that a client can override to respond to cases where the `OutputBuffer` changes arbitrary parts of the name. --- libcxxabi/src/demangle/ItaniumDemangle.h | 91 +++++++++++++++++++------------- libcxxabi/src/demangle/Utility.h | 26 ++++++++- 2 files changed, 79 insertions(+), 38 deletions(-) (limited to 'libcxxabi') diff --git a/libcxxabi/src/demangle/ItaniumDemangle.h b/libcxxabi/src/demangle/ItaniumDemangle.h index eca9ddad66f9..69932e63669b 100644 --- a/libcxxabi/src/demangle/ItaniumDemangle.h +++ b/libcxxabi/src/demangle/ItaniumDemangle.h @@ -283,20 +283,11 @@ public: } void print(OutputBuffer &OB) const { - printLeft(OB); + OB.printLeft(*this); if (RHSComponentCache != Cache::No) - printRight(OB); + OB.printRight(*this); } - // Print the "left" side of this Node into OutputBuffer. - virtual void printLeft(OutputBuffer &) const = 0; - - // Print the "right". This distinction is necessary to represent C++ types - // that appear on the RHS of their subtype, such as arrays or functions. - // Since most types don't have such a component, provide a default - // implementation. - virtual void printRight(OutputBuffer &) const {} - // Print an initializer list of this type. Returns true if we printed a custom // representation, false if nothing has been printed and the default // representation should be used. @@ -312,6 +303,24 @@ public: #ifndef NDEBUG DEMANGLE_DUMP_METHOD void dump() const; #endif + +private: + friend class OutputBuffer; + + // Print the "left" side of this Node into OutputBuffer. + // + // Note, should only be called from OutputBuffer implementations. + // Call \ref OutputBuffer::printLeft instead. + virtual void printLeft(OutputBuffer &) const = 0; + + // Print the "right". This distinction is necessary to represent C++ types + // that appear on the RHS of their subtype, such as arrays or functions. + // Since most types don't have such a component, provide a default + // implementation. + // + // Note, should only be called from OutputBuffer implementations. + // Call \ref OutputBuffer::printRight instead. + virtual void printRight(OutputBuffer &) const {} }; class NodeArray { @@ -460,11 +469,11 @@ public: } void printLeft(OutputBuffer &OB) const override { - Child->printLeft(OB); + OB.printLeft(*Child); printQuals(OB); } - void printRight(OutputBuffer &OB) const override { Child->printRight(OB); } + void printRight(OutputBuffer &OB) const override { OB.printRight(*Child); } }; class ConversionOperatorType final : public Node { @@ -493,7 +502,7 @@ public: template void match(Fn F) const { F(Ty, Postfix); } void printLeft(OutputBuffer &OB) const override { - Ty->printLeft(OB); + OB.printLeft(*Ty); OB += Postfix; } }; @@ -579,7 +588,7 @@ struct AbiTagAttr : Node { std::string_view getBaseName() const override { return Base->getBaseName(); } void printLeft(OutputBuffer &OB) const override { - Base->printLeft(OB); + OB.printLeft(*Base); OB += "[abi:"; OB += Tag; OB += "]"; @@ -646,7 +655,7 @@ public: // We rewrite objc_object* into id. if (Pointee->getKind() != KObjCProtoName || !static_cast(Pointee)->isObjCObject()) { - Pointee->printLeft(OB); + OB.printLeft(*Pointee); if (Pointee->hasArray(OB)) OB += " "; if (Pointee->hasArray(OB) || Pointee->hasFunction(OB)) @@ -665,7 +674,7 @@ public: !static_cast(Pointee)->isObjCObject()) { if (Pointee->hasArray(OB) || Pointee->hasFunction(OB)) OB += ")"; - Pointee->printRight(OB); + OB.printRight(*Pointee); } } }; @@ -731,7 +740,7 @@ public: std::pair Collapsed = collapse(OB); if (!Collapsed.second) return; - Collapsed.second->printLeft(OB); + OB.printLeft(*Collapsed.second); if (Collapsed.second->hasArray(OB)) OB += " "; if (Collapsed.second->hasArray(OB) || Collapsed.second->hasFunction(OB)) @@ -748,7 +757,7 @@ public: return; if (Collapsed.second->hasArray(OB) || Collapsed.second->hasFunction(OB)) OB += ")"; - Collapsed.second->printRight(OB); + OB.printRight(*Collapsed.second); } }; @@ -768,7 +777,7 @@ public: } void printLeft(OutputBuffer &OB) const override { - MemberType->printLeft(OB); + OB.printLeft(*MemberType); if (MemberType->hasArray(OB) || MemberType->hasFunction(OB)) OB += "("; else @@ -780,7 +789,7 @@ public: void printRight(OutputBuffer &OB) const override { if (MemberType->hasArray(OB) || MemberType->hasFunction(OB)) OB += ")"; - MemberType->printRight(OB); + OB.printRight(*MemberType); } }; @@ -800,7 +809,7 @@ public: bool hasRHSComponentSlow(OutputBuffer &) const override { return true; } bool hasArraySlow(OutputBuffer &) const override { return true; } - void printLeft(OutputBuffer &OB) const override { Base->printLeft(OB); } + void printLeft(OutputBuffer &OB) const override { OB.printLeft(*Base); } void printRight(OutputBuffer &OB) const override { if (OB.back() != ']') @@ -809,7 +818,7 @@ public: if (Dimension) Dimension->print(OB); OB += "]"; - Base->printRight(OB); + OB.printRight(*Base); } bool printInitListAsType(OutputBuffer &OB, @@ -853,7 +862,7 @@ public: // by printing out the return types's left, then print our parameters, then // finally print right of the return type. void printLeft(OutputBuffer &OB) const override { - Ret->printLeft(OB); + OB.printLeft(*Ret); OB += " "; } @@ -861,7 +870,7 @@ public: OB.printOpen(); Params.printWithComma(OB); OB.printClose(); - Ret->printRight(OB); + OB.printRight(*Ret); if (CVQuals & QualConst) OB += " const"; @@ -966,6 +975,8 @@ public: FunctionRefQual getRefQual() const { return RefQual; } NodeArray getParams() const { return Params; } const Node *getReturnType() const { return Ret; } + const Node *getAttrs() const { return Attrs; } + const Node *getRequires() const { return Requires; } bool hasRHSComponentSlow(OutputBuffer &) const override { return true; } bool hasFunctionSlow(OutputBuffer &) const override { return true; } @@ -974,10 +985,11 @@ public: void printLeft(OutputBuffer &OB) const override { if (Ret) { - Ret->printLeft(OB); + OB.printLeft(*Ret); if (!Ret->hasRHSComponent(OB)) OB += " "; } + Name->print(OB); } @@ -985,8 +997,9 @@ public: OB.printOpen(); Params.printWithComma(OB); OB.printClose(); + if (Ret) - Ret->printRight(OB); + OB.printRight(*Ret); if (CVQuals & QualConst) OB += " const"; @@ -1326,14 +1339,14 @@ public: template void match(Fn F) const { F(Name, Type); } void printLeft(OutputBuffer &OB) const override { - Type->printLeft(OB); + OB.printLeft(*Type); if (!Type->hasRHSComponent(OB)) OB += " "; } void printRight(OutputBuffer &OB) const override { Name->print(OB); - Type->printRight(OB); + OB.printRight(*Type); } }; @@ -1378,11 +1391,11 @@ public: template void match(Fn F) const { F(Param); } void printLeft(OutputBuffer &OB) const override { - Param->printLeft(OB); + OB.printLeft(*Param); OB += "..."; } - void printRight(OutputBuffer &OB) const override { Param->printRight(OB); } + void printRight(OutputBuffer &OB) const override { OB.printRight(*Param); } }; /// An unexpanded parameter pack (either in the expression or type context). If @@ -1447,13 +1460,13 @@ public: initializePackExpansion(OB); size_t Idx = OB.CurrentPackIndex; if (Idx < Data.size()) - Data[Idx]->printLeft(OB); + OB.printLeft(*Data[Idx]); } void printRight(OutputBuffer &OB) const override { initializePackExpansion(OB); size_t Idx = OB.CurrentPackIndex; if (Idx < Data.size()) - Data[Idx]->printRight(OB); + OB.printRight(*Data[Idx]); } }; @@ -1611,13 +1624,13 @@ struct ForwardTemplateReference : Node { if (Printing) return; ScopedOverride SavePrinting(Printing, true); - Ref->printLeft(OB); + OB.printLeft(*Ref); } void printRight(OutputBuffer &OB) const override { if (Printing) return; ScopedOverride SavePrinting(Printing, true); - Ref->printRight(OB); + OB.printRight(*Ref); } }; @@ -1769,7 +1782,7 @@ public: void printLeft(OutputBuffer &OB) const override { OB += "~"; - Base->printLeft(OB); + OB.printLeft(*Base); } }; @@ -2049,7 +2062,7 @@ public: { ScopedOverride LT(OB.GtIsGt, 0); OB += "<"; - To->printLeft(OB); + OB.printLeft(*To); OB += ">"; } OB.printOpen(); @@ -6180,6 +6193,10 @@ struct ManglingParser : AbstractManglingParser, Alloc> { Alloc>::AbstractManglingParser; }; +inline void OutputBuffer::printLeft(const Node &N) { N.printLeft(*this); } + +inline void OutputBuffer::printRight(const Node &N) { N.printRight(*this); } + DEMANGLE_NAMESPACE_END #if defined(__clang__) diff --git a/libcxxabi/src/demangle/Utility.h b/libcxxabi/src/demangle/Utility.h index f1fad35d60d9..511983ad40f7 100644 --- a/libcxxabi/src/demangle/Utility.h +++ b/libcxxabi/src/demangle/Utility.h @@ -27,6 +27,8 @@ DEMANGLE_NAMESPACE_BEGIN +class Node; + // Stream that AST nodes write their string representation into after the AST // has been parsed. class OutputBuffer { @@ -79,10 +81,24 @@ public: OutputBuffer(const OutputBuffer &) = delete; OutputBuffer &operator=(const OutputBuffer &) = delete; + virtual ~OutputBuffer() {} + operator std::string_view() const { return std::string_view(Buffer, CurrentPosition); } + /// Called by the demangler when printing the demangle tree. By + /// default calls into \c Node::print{Left|Right} but can be overriden + /// by clients to track additional state when printing the demangled name. + virtual void printLeft(const Node &N); + virtual void printRight(const Node &N); + + /// Called when we write to this object anywhere other than the end. + virtual void notifyInsertion(size_t /*Position*/, size_t /*Count*/) {} + + /// Called when we make the \c CurrentPosition of this object smaller. + virtual void notifyDeletion(size_t /*OldPos*/, size_t /*NewPos*/) {} + /// If a ParameterPackExpansion (or similar type) is encountered, the offset /// into the pack that we're currently printing. unsigned CurrentPackIndex = std::numeric_limits::max(); @@ -126,6 +142,8 @@ public: std::memcpy(Buffer, &*R.begin(), Size); CurrentPosition += Size; + notifyInsertion(/*Position=*/0, /*Count=*/Size); + return *this; } @@ -161,14 +179,20 @@ public: DEMANGLE_ASSERT(Pos <= CurrentPosition, ""); if (N == 0) return; + grow(N); std::memmove(Buffer + Pos + N, Buffer + Pos, CurrentPosition - Pos); std::memcpy(Buffer + Pos, S, N); CurrentPosition += N; + + notifyInsertion(Pos, N); } size_t getCurrentPosition() const { return CurrentPosition; } - void setCurrentPosition(size_t NewPos) { CurrentPosition = NewPos; } + void setCurrentPosition(size_t NewPos) { + notifyDeletion(CurrentPosition, NewPos); + CurrentPosition = NewPos; + } char back() const { DEMANGLE_ASSERT(CurrentPosition, ""); -- cgit v1.2.3