On Mar 7, 2008, at 6:06 PM, Ian Lance Taylor wrote:
Tom Tromey <[EMAIL PROTECTED]> writes:
Ian suggested that we delete this information after the FE is
finished. This makes sense, I think, from a memory-saving
perspective. But, that means we will get different kinds of error
output depending on when a diagnostic is emitted, which I think is
pretty unfriendly -- it exposes implementation details of gcc to the
user.
I think that is mostly OK in practice because most diagnostics are
issued by the front end. But I admit that some come from the
middle-end, so there would be an inconsistency.
Another approach would be to only use the carets for parse errors,
which is where they are the most helpful. For a middle-end error like
"assuming signed overflow does not occur when simplifying
multiplication" a caret pointer might be more misleading than
otherwise, as one thing we know for sure is that it would not point at
a multiplication operator.
An important class of middle-end warnings is use of undefined values
and other dataflow warnings in GCC.
What do other compilers do? Reopening the file doesn't work for
standard input, which I admit is an unusual case.
clang points into the original input buffer that was lexed from. This
requires keeping the original files mapped into the address space of
the compiler. However, clang only produces diagnostics from the front-
end, not from the middle-end.
-Chris
