and extern_weak_odr. These are the same as the non-odr versions,
except that they indicate that the global will only be overridden
by an *equivalent* global. In C, a function with weak linkage can
be overridden by a function which behaves completely differently.
This means that IP passes have to skip weak functions, since any
deductions made from the function definition might be wrong, since
the definition could be replaced by something completely different
at link time. This is not allowed in C++, thanks to the ODR
(One-Definition-Rule): if a function is replaced by another at
link-time, then the new function must be the same as the original
function. If a language knows that a function or other global can
only be overridden by an equivalent global, it can give it the
weak_odr linkage type, and the optimizers will understand that it
is alright to make deductions based on the function body. The
code generators on the other hand map weak and weak_odr linkage
to the same thing.
llvm-svn: 66339
Added HasABICall and HasAbsoluteCall (equivalent to gcc -mabicall and
-mno-shared). HasAbsoluteCall is not implemented but HasABICall is the
default for o32 ABI. Now, both should help into a more accurate
relocation types implementation.
Added IsLinux is needed to choose between asm directives.
Instruction name strings cleanup.
AsmPrinter improved.
llvm-svn: 53551
- Modifications from the last patch included
(issues pointed by Evan Cheng are now fixed).
- Added more MipsI instructions.
- Added more patterns to match branch instructions.
llvm-svn: 37461
Duncan Sands