When the main file is preprocessed and we change `MainFileName` to the
original source file name (e.g. `a.i => a.c`), the source manager does
not contain `a.c`, but we incorrectly associate the DIFile(a.c) with
md5(a.i). This causes CGDebugInfo::emitFunctionStart to create a
duplicate DIFile and leads to a spurious "inconsistent use of MD5
checksums" warning.
```
% cat a.c
void f() {}
% clang -c -g a.c # no warning
% clang -E a.c -o a.i && clang -g -S a.i && clang -g -c a.s
a.s:9:2: warning: inconsistent use of MD5 checksums
.file 1 "a.c"
^
% grep DIFile a.ll
!1 = !DIFile(filename: "a.c", directory: "/tmp/c", checksumkind: CSK_MD5, checksum: "c5b2e246df7d5f53e176b097a0641c3d")
!11 = !DIFile(filename: "a.c", directory: "/tmp/c")
% grep 'file.*a.c' a.s
.file "a.c"
.file 0 "/tmp/c" "a.c" md5 0x2d14ea70fee15102033eb8d899914cce
.file 1 "a.c"
```
Fix#56378 by disassociating md5(a.i) with a.c.
This may be a breaking change for consumers if they're trying to detect
if code is C or C++, since it'll start using new codes that they may not
be ready to recognize, in which case they may fall back to non-C
handling.
This caused regressions due to PS4 having a different default for C
language version than other targets. Those tests were adapted to be
relaxed about which C version is used.
This reapplies commit 3c312e48f325c1b1ee11404ee6cfa08ee00037b0
Which was reverted by commit 6ab6085c77ef9bcdabf842342f63fba4291791a4.
Differential Revision: https://reviews.llvm.org/D138597
Some buildbots are failing in Clang and LLDB tests. (I guess the LLDB
failure is due to the explicit C language tests in DwarfUnit.cpp that
need to be updated - not sure what the Clang failures are about, they
seem to be still emitting C99 when we're expecting C11 and I checked
those tests pass... maybe systems with a different C language version
default?)
This reverts commit 3c312e48f325c1b1ee11404ee6cfa08ee00037b0.
This may be a breaking change for consumers if they're trying to detect
if code is C or C++, since it'll start using new codes that they may not
be ready to recognize, in which case they may fall back to non-C
handling.
Differential Revision: https://reviews.llvm.org/D138597
Summary:
Even in the case of the input file is a preprocessed source, clang uses the file name of the preprocesses source for debug info (DW_AT_name attribute for DW_TAG_compile_unit). However, gcc uses the file name specified in the first linemarker instead. This makes more sense because the one specified in the linemarker represents the "actual" source file name.
Clang already uses the file name specified in the first linemarker for Module name (https://github.com/llvm-mirror/clang/blob/master/lib/Frontend/FrontendAction.cpp#L779) if the input is preprocessed. This patch makes clang to use the same value for debug info as well.
Reviewers: compnerd, rnk, dblaikie, rsmith
Reviewed By: rnk
Subscribers: aprantl, cfe-commits
Differential Revision: https://reviews.llvm.org/D36474
llvm-svn: 311037
