Commit Graph

12 Commits

Author SHA1 Message Date
Sjoerd Meijer 3d9a0445cc Recommit #2 "[Driver] Default to -fno-common for all targets"
After a first attempt to fix the test-suite failures, my first recommit
caused the same failures again. I had updated CMakeList.txt files of
tests that needed -fcommon, but it turns out that there are also
Makefiles which are used by some bots, so I've updated these Makefiles
now too.

See the original commit message for more details on this change:
0a9fc9233e
2020-03-09 19:57:03 +00:00
Sjoerd Meijer f35d112efd Revert "Recommit "[Driver] Default to -fno-common for all targets""
This reverts commit 2c36c23f34.

Still problems in the test-suite, which I really thought I had fixed...
2020-03-09 10:37:28 +00:00
Sjoerd Meijer 2c36c23f34 Recommit "[Driver] Default to -fno-common for all targets"
This includes fixes for:
- test-suite: some benchmarks need to be compiled with -fcommon, see D75557.
- compiler-rt: one test needed -fcommon, and another a change, see D75520.
2020-03-09 10:07:37 +00:00
Sjoerd Meijer 4e363563fa Revert "[Driver] Default to -fno-common for all targets"
This reverts commit 0a9fc9233e.

Going to look at the asan failures.

I find the failures in the test suite weird, because they look
like compile time test and I don't understand how that can be
failing, but will have a brief look at that too.
2020-03-03 10:00:36 +00:00
Sjoerd Meijer 0a9fc9233e [Driver] Default to -fno-common for all targets
This makes -fno-common the default for all targets because this has performance
and code-size benefits and is more language conforming for C code.
Additionally, GCC10 also defaults to -fno-common and so we get consistent
behaviour with GCC.

With this change, C code that uses tentative definitions as definitions of a
variable in multiple translation units will trigger multiple-definition linker
errors. Generally, this occurs when the use of the extern keyword is neglected
in the declaration of a variable in a header file. In some cases, no specific
translation unit provides a definition of the variable. The previous behavior
can be restored by specifying -fcommon.

As GCC has switched already, we benefit from applications already being ported
and existing documentation how to do this. For example:
- https://gcc.gnu.org/gcc-10/porting_to.html
- https://wiki.gentoo.org/wiki/Gcc_10_porting_notes/fno_common

Differential revision: https://reviews.llvm.org/D75056
2020-03-03 09:15:07 +00:00
Adrian Prantl bc068586ac Revert "Revert r241620 and follow-up commits" and move the initialization
of the llvm targets from clang/CodeGen into ClangCheck.cpp and CIndex.cpp.

llvm-svn: 241653
2015-07-08 01:00:30 +00:00
Adrian Prantl 142ec39739 Revert r241620 and follow-up commits while investigating linux buildbot failures.
llvm-svn: 241642
2015-07-07 23:19:46 +00:00
Adrian Prantl e50371b948 Wrap clang modules and pch files in an object file container.
This patch adds ObjectFilePCHContainerOperations uses the LLVM backend
to put the contents of a PCH into a __clangast section inside a COFF, ELF,
or Mach-O object file container.

This is done to facilitate module debugging by makeing it possible to
store the debug info for the types defined by a module alongside the AST.

rdar://problem/20091852

llvm-svn: 241620
2015-07-07 20:11:29 +00:00
Adrian Prantl cbc368c5b5 Revert "Wrap clang module files in a Mach-O, ELF, or COFF container."
llvm-svn: 230454
2015-02-25 02:44:04 +00:00
Adrian Prantl 8bf7af3de8 Wrap clang module files in a Mach-O, ELF, or COFF container.
This is a necessary prerequisite for debugging with modules.
The .pcm files become containers that hold the serialized AST which allows
us to store debug information in the module file that can be shared by all
object files that were built importing the module.

This reapplies r230044 with a fixed configure+make build and updated
dependencies and testcase requirements. Over the last iteration this
version adds
- missing target requirements for testcases that specify an x86 triple,
- a missing clangCodeGen.a dependency to libClang.a in the make build.

rdar://problem/19104245

llvm-svn: 230423
2015-02-25 01:31:45 +00:00
Douglas Gregor 2ed0ee1ace Eliminate the -chained-pch flag and all of the frontend and libclang options associated with it. Chained PCH is the only way to build a PCH file that includes another PCH file
llvm-svn: 138597
2011-08-25 22:54:01 +00:00
Sebastian Redl 887d6b08fd Add a test case for tentative definitions in chained PCH. Fix a bug that completely messed up source locations and thus caused a crash whenever a diagnostic was emitted in chained PCH files.
llvm-svn: 109660
2010-07-28 21:07:02 +00:00