clang::MacroExpansionContext Class Reference

MacroExpansionContext tracks the macro expansions processed by the Preprocessor. More...

#include "clang/Analysis/MacroExpansionContext.h"

Public Member Functions
	MacroExpansionContext (const LangOptions &LangOpts)
	Creates a MacroExpansionContext.
void	registerForPreprocessor (Preprocessor &PP)
	Register the necessary callbacks to the Preprocessor to record the expansion events and the generated tokens.
std::optional< StringRef >	getExpandedText (SourceLocation MacroExpansionLoc) const
std::optional< StringRef >	getOriginalText (SourceLocation MacroExpansionLoc) const
LLVM_DUMP_METHOD void	dumpExpansionRangesToStream (raw_ostream &OS) const
LLVM_DUMP_METHOD void	dumpExpandedTextsToStream (raw_ostream &OS) const
LLVM_DUMP_METHOD void	dumpExpansionRanges () const
LLVM_DUMP_METHOD void	dumpExpandedTexts () const

Friends
class	detail::MacroExpansionRangeRecorder

Detailed Description

MacroExpansionContext tracks the macro expansions processed by the Preprocessor.

It means that it can track source locations from a single translation unit. For every macro expansion it can tell you what text will be substituted.

It was designed to deal with:

• regular macros
• macro functions
• variadic macros
• transitive macro expansions
• macro redefinition
• unbalanced parenthesis

void bar();
#define retArg(x) x
#define retArgUnclosed retArg(bar()
#define BB CC
#define applyInt BB(int)
#define CC(x) retArgUnclosed
 
void unbalancedMacros() {
  applyInt  );
//^~~~~~~~~~^ is the substituted range
// Substituted text is "applyInt  )"
// Expanded text is "bar()"
}
 
#define expandArgUnclosedCommaExpr(x) (x, bar(), 1
#define f expandArgUnclosedCommaExpr
 
void unbalancedMacros2() {
  int x =  f(f(1))  ));  // Look at the parenthesis!
//         ^~~~~~^ is the substituted range
// Substituted text is "f(f(1))"
// Expanded text is "((1,bar(),1,bar(),1"
}

Remarks

Currently we don't respect the whitespaces between expanded tokens, so the output for this example might differ from the -E compiler invocation.

All whitespaces are consumed while constructing the expansion. After all identifier a single space inserted to produce a valid C code even if identifier follows an other identifiers such as variable declarations.

MacroExpansionContext object must outlive the Preprocessor parameter.

Definition at line 73 of file MacroExpansionContext.h.

Constructor & Destructor Documentation

MacroExpansionContext()

MacroExpansionContext::MacroExpansionContext ( const LangOptions & LangOpts )

explicit

Creates a MacroExpansionContext.

Remarks

You must call registerForPreprocessor to set the required onTokenLexed callback and the PPCallbacks.

Definition at line 86 of file MacroExpansionContext.cpp.

Member Function Documentation

dumpExpandedTexts()

void MacroExpansionContext::dumpExpandedTexts

(

)

const

Definition at line 138 of file MacroExpansionContext.cpp.

References dumpExpandedTextsToStream().

dumpExpandedTextsToStream()

void MacroExpansionContext::dumpExpandedTextsToStream

(

raw_ostream &

OS

)

const

Definition at line 160 of file MacroExpansionContext.cpp.

Referenced by dumpExpandedTexts().

dumpExpansionRanges()

void MacroExpansionContext::dumpExpansionRanges

(

)

const

Definition at line 135 of file MacroExpansionContext.cpp.

References dumpExpansionRangesToStream().

dumpExpansionRangesToStream()

void MacroExpansionContext::dumpExpansionRangesToStream

(

raw_ostream &

OS

)

const

Definition at line 142 of file MacroExpansionContext.cpp.

Referenced by dumpExpansionRanges().

getExpandedText()

std::optional< StringRef > MacroExpansionContext::getExpandedText

(

SourceLocation

MacroExpansionLoc

)

const

Parameters

MacroExpansionLoc

Must be the expansion location of a macro.

Returns

The textual representation of the token sequence which was substituted in place of the macro after the preprocessing. If no macro was expanded at that location, returns std::nullopt.

Definition at line 101 of file MacroExpansionContext.cpp.

References clang::SourceLocation::isMacroID().

Referenced by getExpandedMacro().

getOriginalText()

std::optional< StringRef > MacroExpansionContext::getOriginalText

(

SourceLocation

MacroExpansionLoc

)

const

Parameters

MacroExpansionLoc

Must be the expansion location of a macro.

Returns

The text from the original source code which were substituted by the macro expansion chain from the given location. If no macro was expanded at that location, returns std::nullopt.

Definition at line 119 of file MacroExpansionContext.cpp.

References clang::CharSourceRange::getCharRange(), clang::Lexer::getSourceText(), and clang::SourceLocation::isMacroID().

registerForPreprocessor()

void MacroExpansionContext::registerForPreprocessor

(

Preprocessor &

PP

)

Register the necessary callbacks to the Preprocessor to record the expansion events and the generated tokens.

Must ensure that this object outlives the given Preprocessor.

Definition at line 89 of file MacroExpansionContext.cpp.

References clang::Preprocessor::getSourceManager(), and Tok.

Friends And Related Symbol Documentation

detail::MacroExpansionRangeRecorder

friend class detail::MacroExpansionRangeRecorder

friend

Definition at line 105 of file MacroExpansionContext.h.

References Tok.

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The documentation for this class was generated from the following files:

• include/clang/Analysis/MacroExpansionContext.h
• lib/Analysis/MacroExpansionContext.cpp