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[Demangling] Add name and parameters range tracking when demangling a name #81511

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[Demangling] Add name and parameters range tracking when demangling a name #81511

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0245da0
add range tracking when demangling a name
charles-zablit May 14, 2025
87a5b83
use unique_ptr instead of PointerStorage
charles-zablit May 15, 2025
5a0f86d
fixup! use unique_ptr instead of PointerStorage
charles-zablit May 15, 2025
da099b5
Revert "fixup! use unique_ptr instead of PointerStorage"
charles-zablit May 15, 2025
1cc6d21
Revert "use unique_ptr instead of PointerStorage"
charles-zablit May 15, 2025
e539666
move the logic outside of the NodePrinter class
charles-zablit May 15, 2025
e0700fb
revert swift-demangle changes
charles-zablit May 19, 2025
05a9397
fixup! revert swift-demangle changes
charles-zablit May 19, 2025
7aa7100
fixup! revert swift-demangle changes
charles-zablit May 19, 2025
eb11777
document NodePrinter
charles-zablit May 27, 2025
9bf53cc
create a separate API to avoid access to a string that has been moved
charles-zablit May 29, 2025
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112 changes: 100 additions & 12 deletions include/swift/Demangling/Demangle.h
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
#ifndef SWIFT_DEMANGLING_DEMANGLE_H
#define SWIFT_DEMANGLING_DEMANGLE_H

#include "swift/Demangling/Demangle.h"
#include "swift/Demangling/Errors.h"
#include "swift/Demangling/ManglingFlavor.h"
#include "swift/Demangling/NamespaceMacros.h"
Expand Down Expand Up @@ -234,6 +235,18 @@ class Node {
public:
Kind getKind() const { return NodeKind; }

bool shouldTrackNameRange() const {
switch (getKind()) {
case Kind::Function:
case Kind::Constructor:
case Kind::Allocator:
case Kind::ExplicitClosure:
return true;
default:
return false;
}
}

bool isSimilarTo(const Node *other) const {
if (NodeKind != other->NodeKind
|| NodePayloadKind != other->NodePayloadKind)
Expand Down Expand Up @@ -417,6 +430,10 @@ bool isOldFunctionTypeMangling(llvm::StringRef mangledName);

class Demangler;

class DemanglerPrinter;

class TrackingDemanglerPrinter;

/// The demangler context.
///
/// It owns the allocated nodes which are created during demangling.
Expand Down Expand Up @@ -472,9 +489,10 @@ class Context {
/// prefix: _T, _T0, $S, _$S.
///
/// \returns The demangled string.
std::string demangleSymbolAsString(
llvm::StringRef MangledName,
const DemangleOptions &Options = DemangleOptions());
std::string
demangleSymbolAsString(llvm::StringRef MangledName,
const DemangleOptions &Options = DemangleOptions(),
DemanglerPrinter *printer = nullptr);

/// Demangle the given type and return the readable name.
///
Expand Down Expand Up @@ -531,7 +549,8 @@ class Context {
/// \returns The demangled string.
std::string
demangleSymbolAsString(const char *mangledName, size_t mangledNameLength,
const DemangleOptions &options = DemangleOptions());
const DemangleOptions &options = DemangleOptions(),
DemanglerPrinter *printer = nullptr);

/// Standalone utility function to demangle the given symbol as string.
///
Expand All @@ -541,11 +560,12 @@ demangleSymbolAsString(const char *mangledName, size_t mangledNameLength,
/// \returns The demangled string.
inline std::string
demangleSymbolAsString(const std::string &mangledName,
const DemangleOptions &options = DemangleOptions()) {
return demangleSymbolAsString(mangledName.data(), mangledName.size(),
options);
const DemangleOptions &options = DemangleOptions(),
DemanglerPrinter *printer = nullptr) {
return demangleSymbolAsString(mangledName.data(), mangledName.size(), options,
printer);
}

/// Standalone utility function to demangle the given symbol as string.
///
/// If performance is an issue when demangling multiple symbols,
Expand All @@ -554,9 +574,10 @@ demangleSymbolAsString(const std::string &mangledName,
/// \returns The demangled string.
inline std::string
demangleSymbolAsString(llvm::StringRef MangledName,
const DemangleOptions &Options = DemangleOptions()) {
return demangleSymbolAsString(MangledName.data(),
MangledName.size(), Options);
const DemangleOptions &Options = DemangleOptions(),
DemanglerPrinter *printer = nullptr) {
return demangleSymbolAsString(MangledName.data(), MangledName.size(), Options,
printer);
}

/// Standalone utility function to demangle the given type as string.
Expand Down Expand Up @@ -730,7 +751,8 @@ ManglingErrorOr<const char *> mangleNodeAsObjcCString(NodePointer node,
/// \returns A string representing the demangled name.
///
std::string nodeToString(NodePointer Root,
const DemangleOptions &Options = DemangleOptions());
const DemangleOptions &Options = DemangleOptions(),
DemanglerPrinter *printer = nullptr);

/// Transforms a mangled key path accessor thunk helper
/// into the identfier/subscript that would be used to invoke it in swift code.
Expand Down Expand Up @@ -777,15 +799,81 @@ class DemanglerPrinter {

llvm::StringRef getStringRef() const { return Stream; }

size_t getStreamLength() { return Stream.length(); }

/// Shrinks the buffer.
void resetSize(size_t toPos) {
assert(toPos <= Stream.size());
Stream.resize(toPos);
}

/// Mark the start of the name of a function.
virtual void startName() {}

/// Mark the end of the name of a function.
virtual void endName() {}

/// Mark the start of the parameters of a function.
///
/// \param depth Current depth of the parameters that are being printed.
virtual void startParameters(unsigned depth) {}

/// Mark the end of the parameters of a function.
///
/// \param depth Current depth of the parameters that are being printed.
virtual void endParameters(unsigned depth) {}

virtual ~DemanglerPrinter() {}

private:
std::string Stream;
};

/// A class for printing to a std::string while tracking ranges.
class TrackingDemanglerPrinter : public swift::Demangle::DemanglerPrinter {
public:
size_t getNameStart() { return baseNameRange.first; }
size_t getNameEnd() { return baseNameRange.second; }
size_t getParametersStart() { return parametersRange.first; }
size_t getParametersEnd() { return parametersRange.second; }
bool hasBaseName() { return baseNameRange.first < baseNameRange.second; }
bool hasParameters() {
return parametersRange.first < parametersRange.second;
}

void startName() override {
if (!hasBaseName())
baseNameRange.first = getStreamLength();
}

void endName() override {
if (!hasBaseName())
baseNameRange.second = getStreamLength();
}

void startParameters(unsigned depth) override {
if (parametersDepth || !hasBaseName() || hasParameters()) {
return;
}
parametersRange.first = getStreamLength();
parametersDepth = depth;
}

void endParameters(unsigned depth) override {
if (!parametersDepth || *parametersDepth != depth || hasParameters()) {
return;
}
parametersRange.second = getStreamLength();
}

private:
std::pair<size_t, size_t> baseNameRange;

std::pair<size_t, size_t> parametersRange;

std::optional<unsigned> parametersDepth;
};

/// Returns a the node kind \p k as string.
const char *getNodeKindString(swift::Demangle::Node::Kind k);

Expand Down
10 changes: 6 additions & 4 deletions lib/Demangling/Context.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -56,11 +56,12 @@ NodePointer Context::demangleTypeAsNode(llvm::StringRef MangledName) {
#if SWIFT_STDLIB_HAS_TYPE_PRINTING

std::string Context::demangleSymbolAsString(llvm::StringRef MangledName,
const DemangleOptions &Options) {
const DemangleOptions &Options,
DemanglerPrinter *printer) {
NodePointer root = demangleSymbolAsNode(MangledName);
if (!root) return MangledName.str();

std::string demangling = nodeToString(root, Options);
std::string demangling = nodeToString(root, Options, printer);
if (demangling.empty())
return MangledName.str();
return demangling;
Expand Down Expand Up @@ -269,10 +270,11 @@ std::string Context::getModuleName(llvm::StringRef mangledName) {

std::string demangleSymbolAsString(const char *MangledName,
size_t MangledNameLength,
const DemangleOptions &Options) {
const DemangleOptions &Options,
DemanglerPrinter *printer) {
Context Ctx;
return Ctx.demangleSymbolAsString(StringRef(MangledName, MangledNameLength),
Options);
Options, printer);
}

std::string demangleTypeAsString(const char *MangledName,
Expand Down
25 changes: 20 additions & 5 deletions lib/Demangling/NodePrinter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -169,13 +169,19 @@ static StringRef toString(ValueWitnessKind k) {

class NodePrinter {
private:
DemanglerPrinter Printer;
std::unique_ptr<DemanglerPrinter> PrinterStorage;
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Having two separate members feels a bit weird. Could we just make Printer a std::unique_ptr<DemanglerPrinter>? And take a std::unique_ptr<DemanglerPrinter> in the constructor? And if it's nullptr we just make_unique

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It didn't feel right yes. I initially wanted to pass an std::optional, but couldn't because it wouldn't allow me to pass in a child class. I will give it another go with your suggestion.

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I think I managed to get it to a good state. I decided to use a template instead of changing all the Printer << ... calls to (*Printer) << .... I found out about decltype on this SO thread: https://stackoverflow.com/questions/18815221/what-is-decltype-and-how-is-it-used

DemanglerPrinter &Printer;
DemangleOptions Options;
bool SpecializationPrefixPrinted = false;
bool isValid = true;

public:
NodePrinter(DemangleOptions options) : Options(options) {}
NodePrinter(DemangleOptions options, DemanglerPrinter *printer = nullptr)
: PrinterStorage(),
Printer(printer
? *printer
: *(PrinterStorage = std::make_unique<DemanglerPrinter>())),
Options(options) {}

std::string printRoot(NodePointer root) {
isValid = true;
Expand Down Expand Up @@ -802,6 +808,7 @@ class NodePrinter {
return;
}

Printer.startParameters(depth);
NodePointer Parameters = ParameterType->getFirstChild();
assert(Parameters->getKind() == Node::Kind::Type);
Parameters = Parameters->getFirstChild();
Expand All @@ -814,6 +821,7 @@ class NodePrinter {
} else {
Printer << "(_:)";
}
Printer.endParameters(depth);
return;
}

Expand Down Expand Up @@ -853,6 +861,7 @@ class NodePrinter {
},
[&]() { Printer << (showTypes ? ", " : ""); });
Printer << ')';
Printer.endParameters(depth);
}

void printFunctionType(NodePointer LabelList, NodePointer node,
Expand Down Expand Up @@ -3576,7 +3585,9 @@ NodePointer NodePrinter::printEntity(NodePointer Entity, unsigned depth,
Printer << '.';
}
}

if (Entity->shouldTrackNameRange()) {
Printer.startName();
}
if (hasName || !OverwriteName.empty()) {
if (!ExtraName.empty() && MultiWordName) {
Printer << ExtraName;
Expand Down Expand Up @@ -3606,6 +3617,9 @@ NodePointer NodePrinter::printEntity(NodePointer Entity, unsigned depth,
if (ExtraIndex >= 0)
Printer << ExtraIndex;
}
if (Entity->shouldTrackNameRange()) {
Printer.endName();
}
if (TypePr != TypePrinting::NoType) {
NodePointer type = getChildIf(Entity, Node::Kind::Type);
assert(type && "malformed entity");
Expand Down Expand Up @@ -3836,11 +3850,12 @@ std::string Demangle::keyPathSourceString(const char *MangledName,
}

std::string Demangle::nodeToString(NodePointer root,
const DemangleOptions &options) {
const DemangleOptions &options,
DemanglerPrinter *printer) {
if (!root)
return "";

return NodePrinter(options).printRoot(root);
return NodePrinter(options, printer).printRoot(root);
}

#endif
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