Current implementation may end up emitting an undefined reference for
an "inline __attribute__((always_inline))" function by generating an
"available_externally alwaysinline" IR function for it and then failing to
inline all the calls. This happens when a call to such function is in dead
code. As the inliner is an SCC pass, it does not process dead code.
Libc++ relies on the compiler never emitting such undefined reference.
With this patch, we emit a pair of
1. internal alwaysinline definition (called F.alwaysinline)
2a. A stub F() { musttail call F.alwaysinline }
-- or, depending on the linkage --
2b. A declaration of F.
The frontend ensures that F.inlinefunction is only used for direct
calls, and the stub is used for everything else (taking the address of
the function, really). Declaration (2b) is emitted in the case when
"inline" is meant for inlining only (like __gnu_inline__ and some
other cases).
This approach, among other nice properties, ensures that alwaysinline
functions are always internal, making it impossible for a direct call
to such function to produce an undefined symbol reference.
This patch is based on ideas by Chandler Carruth and Richard Smith.
llvm-svn: 247494
Current implementation may end up emitting an undefined reference for
an "inline __attribute__((always_inline))" function by generating an
"available_externally alwaysinline" IR function for it and then failing to
inline all the calls. This happens when a call to such function is in dead
code. As the inliner is an SCC pass, it does not process dead code.
Libc++ relies on the compiler never emitting such undefined reference.
With this patch, we emit a pair of
1. internal alwaysinline definition (called F.alwaysinline)
2a. A stub F() { musttail call F.alwaysinline }
-- or, depending on the linkage --
2b. A declaration of F.
The frontend ensures that F.inlinefunction is only used for direct
calls, and the stub is used for everything else (taking the address of
the function, really). Declaration (2b) is emitted in the case when
"inline" is meant for inlining only (like __gnu_inline__ and some
other cases).
This approach, among other nice properties, ensures that alwaysinline
functions are always internal, making it impossible for a direct call
to such function to produce an undefined symbol reference.
This patch is based on ideas by Chandler Carruth and Richard Smith.
llvm-svn: 247465
A leftover -S was generating unwanted output in the source tree overriding
-only flags that normally disable output.
This reverts commit r210323 and implements the proper fix.
Reported by Timur Iskhodzhanov!
llvm-svn: 210326
Instead of disembodied diagnostics when debug info is disabled it's now
possible to identify the associated function's location in order to provide
some amount of of context.
We use the definition's body right brace location to differentiate the fallback
from diagnostics that genuinely relate to the function declaration itself (a
convention also used by gcc).
llvm-svn: 210294
Summary:
When using #line directives, FileManager::getFile() will return a nil
entry. This triggers an assert in translateFileLineCol().
This patch handles nil FileEntry instances by emitting a note that the
location could not be translated back to a SourceLocation. I don't
really like this solution, but we are translating presumed locations,
so some information has already been lost.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D3625
llvm-svn: 208315
Evgeniy Stepanov