A small example on how to initiate header search and configure CFG from an already formed AST.

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#1

Since clang branch 2.7 onwards the InitHeaderSearch and InitPreprocessor seem to have been removed from the include library ( to be replaced by HeaderSearchOptions) . It will be really helpful if someone can demonstrate via a small piece of code - how to initiate search paths of header files included in a file you want to parse ( which previously was done by InitHeaderSearch )

Also can someone give a small snippet of code to demonstrate forming a CFG class( branch 2.7 + ) given an already formed ASTContext class and maybe a RecursiveASTVisitor to traverse the AST .

#2

Since clang branch 2.7 onwards the InitHeaderSearch and InitPreprocessor seem to have been removed from the include library ( to be replaced by HeaderSearchOptions) . It will be really helpful if someone can demonstrate via a small piece of code - how to initiate search paths of header files included in a file you want to parse ( which previously was done by InitHeaderSearch )

Also can someone give a small snippet of code to demonstrate forming a CFG class( branch 2.7 + ) given an already formed ASTContext class and maybe a RecursiveASTVisitor to traverse the AST .

Thanks and Regards ,

Parijat

#3

Probably the best way to construct a CFG is to have an AnalysisContext object do it for you. You can construct an AnalysisContext object using a FunctionDecl, and then call the getCFG() method to have it lazily create a CFG. When the AnalysisContext object is destroyed, the CFG will be destroyed as well.

#4

What is the TranslationUnit required as a parameter for AnalysisContext creation ?

Thanks and Regards
Parijat

#5

It’s optional, and you can leave it NULL. It’s there to support cross-translation unit analysis (in the future).

#6

Thanks a lot ! :slight_smile: .By the way can someone guide me on how do I need to go about initializing header search paths because my parser collapses when it comes across included header files in the test code.

This is how I have initialized the preprocessor :

llvm::raw_ostream *os = NULL;

llvm::raw_ostream *ps = NULL;

const DiagnosticOptions diagop;

bool OwnsOutputStream=false;

TextDiagnosticPrinter diagClient(*os,diagop,OwnsOutputStream);

Diagnostic diags(&diagClient);

LangOptions opts;

TargetOptions to;

const std::string& triple = LLVM_HOSTTRIPLE;

to.ABI="";

to.CXXABI=“itanium”;

to.CPU="";

to.Features.clear();

to.Triple=triple;

TargetInfo* target = TargetInfo::CreateTargetInfo(diags,to);

SourceManager sm(diags);

FileManager fm;

HeaderSearch headers(fm);

Preprocessor pp(diags,opts,*target,sm,headers);

Any suggestions / modifications needed to make sure the included file search paths are taken care while parsing a test file ?

Thanks and Regards ,
Parijat