After r300027 implicit builds might fail when updating the SDK on
darwin. Make validation of system headers default when implicit modules
is on and allow modules to be rebuild when system headers change.
rdar://problem/19767523
llvm-svn: 330240
In this mode, there is no need to load any module map and the programmer can
simply use "@import" syntax to load the module directly from a prebuilt
module path. When loading from prebuilt module path, we don't support
rebuilding of the module files and we ignore compatible configuration
mismatches.
rdar://27290316
Differential Revision: http://reviews.llvm.org/D23125
llvm-svn: 279096
With PCH+Module, sometimes compiler gives a hard error:
Module file ‘<some-file path>.pcm' is out of date and needs to be rebuilt
This happens when we have a pch importing a module and the module gets
overwritten by another compiler instance after we build the pch (one example is
that both compiler instances hash to the same pcm file but use different
diagnostic options). When we try to load the pch later on, the compiler notices
that the imported module is out of date (modification date, size do not match)
but it can't handle this out of date pcm (i.e it does not know how to rebuild
the pch).
This commit introduces a new command line option so for PCH + module, we can
turn on this option and if two compiler instances only differ in diagnostic
options, the latter instance will not invalidate the original pcm.
rdar://26675801
Differential Revision: http://reviews.llvm.org/D22773
llvm-svn: 276769
Unsurprisingly, changing a file modification time to a specific
date/time doesn't give the same epoch time everywhere. Just make the
file move into the past and look at only the first few digits of the
epoch time.
llvm-svn: 214589
Build systems tend to traffic in files and modification times, so having
them touch a file at the beginning of the build can be easier than
having them update the compile command they use every time they build.
llvm-svn: 214577
When enabled, always validate the system headers when loading a module.
The end result of this is that when these headers change, we will notice
and rebuild the module.
llvm-svn: 203630
the build
When Clang loads the module, it verifies the user source files that the module
was built from. If any file was changed, the module is rebuilt. There are two
problems with this:
1. correctness: we don't verify system files (there are too many of them, and
stat'ing all of them would take a lot of time);
2. performance: the same module file is verified again and again during a
single build.
This change allows the build system to optimize source file verification. The
idea is based on the fact that while the project is being built, the source
files don't change. This allows us to verify the module only once during a
single build session. The build system passes a flag,
-fbuild-session-timestamp=, to inform Clang of the time when the build started.
The build system also requests to enable this feature by passing
-fmodules-validate-once-per-build-session. If these flags are not passed, the
behavior is not changed. When Clang verifies the module the first time, it
writes out a timestamp file. Then, when Clang loads the module the second
time, it finds a timestamp file, so it can compare the verification timestamp
of the module with the time when the build started. If the verification
timestamp is too old, the module is verified again, and the timestamp file is
updated.
llvm-svn: 201224
- There is no reason to have a modules specific flag for disabling
autolinking. Instead, convert the existing flag into -fno-autolink (which
should cover other autolinking code generation paths like #pragmas if and
when we support them).
llvm-svn: 179612
Bruno Cardoso Lopes