[cfe-dev] Problem with retrieving the BinaryOperator RHS end location

[Nat! via cfe-dev]

It turns out the fix suggestion - at least as I implemented it - works 
for simple cases, but not in general.

```
endBuf  = SM->getCharacterData( Stmt->getRHS()->getEndLoc());
endBuf += Lexer::MeasureTokenLength( Stmt->getEndLoc(), *SM, 
TheRewriter.getLangOpts());
```

I believe the problem is that the SourceManager I am using
to "measure" the length is looking at the unmodified sourcecode. But
the RewriteBuffer may already contain changes.

So in my example if I am looking at `x = yyy` at the source but
in the rewrite buffer its now `x=yyy_renamed` it will not take the
extra characters into account.

I should be measuring the contents of the RewriteBuffer instead,
with likely another SourceManager, but I lack the expertise to set
this up.

Ciao
    Nat!



Nat! via cfe-dev schrieb:
> I am just trying to print the whole BinaryOperator statement text
> verbatim, but I can not get the end of the statement location.
>
>
> ```
>
> bool VisitBinaryOperator(BinaryOperator  *Stmt) {
>          const char       *startBuf;
>          const char       *endBuf;
>          SourceManager    *SM;
>
>          SM = &TheRewriter.getSourceMgr(); // based on Rewriter
>          startBuf = SM->getCharacterData( Stmt->getLHS()->getBeginLoc());
>          endBuf   = SM->getCharacterData( Stmt->getRHS()->getEndLoc());
>          fprintf( stderr, "write: \"%.*s\"\n", (int) (endBuf -
> startBuf), startBuf);
>          return( true);
> }
>
> ```
>
>
> For an input of:
>
> ```
>
> void   x( void)
> {
>     void  (*y)(void);
>
>     y = x;
> }
>
> ```
>
>
> I get
>
> ```
>
> write: "y = "
>
> ```
>
>
> This is the dump of the AST:
>
> ```
>
> FunctionDecl 0x19d3bd8 </home/src/srcL/llvm-clang-samples/y.m:1:1,
> line:6:1> line:1:8 referenced x 'void (void)'
> `-CompoundStmt 0x19d3ec8 <line:2:1, line:6:1>
>    |-DeclStmt 0x19d3e38 <line:3:4, col:20>
>    | `-VarDecl 0x19d3dd8 <col:4, col:19> col:12 used y 'void (*)(void)'
>    `-BinaryOperator 0x19d3ea8 <line:5:4, col:8> 'void (*)(void)' '='
>      |-DeclRefExpr 0x19d3e50 <col:4> 'void (*)(void)' lvalue Var
> 0x19d3dd8 'y' 'void (*)(void)'
>      `-ImplicitCastExpr 0x19d3e90 <col:8> 'void (*)(void)'
> <FunctionToPointerDecay>
>        `-DeclRefExpr 0x19d3e70 <col:8> 'void (void)' Function 0x19d3bd8
> 'x' 'void (void)'
> ```
>
> This is my first foray into clang rewriting...
>
>
> Ciao
>
>    Nat!
>
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