interpreter: detect and pass compiler to be used for linker tests

Allow using the links method to test that the C++ driver (e.g. g++) can be used to
link C objects.  One usecase is that the C compiler's libsanitizer might not be
compatible with the one included by the C++ driver.

This is theoretically backwards-incompatible, but it should be treated as a
bugfix in my opinion. There is no way in Meson to compile a .c file with the
C++ driver as part of a build target, therefore there would be no reason to
do something like meson.get_compiler(meson.get_compiler('cpp').links(files('main.c')).

Fixes: #7703

2 files changed, 4 insertions, 0 deletions

diff --git a/mesonbuild/compilers/__init__.py b/mesonbuild/compilers/__init__.py
index 3d39c9b..895f98d 100644
--- a/mesonbuild/compilers/__init__.py
+++ b/mesonbuild/compilers/__init__.py
@@ -34,6 +34,7 @@ __all__ = [
     'is_known_suffix',
     'lang_suffixes',
     'sort_clink',
+    'SUFFIX_TO_LANG',
 
     'compiler_from_language',
     'detect_compiler_for',
@@ -148,6 +149,7 @@ from .compilers import (
     lang_suffixes,
     LANGUAGES_USING_LDFLAGS,
     sort_clink,
+    SUFFIX_TO_LANG,
 )
 from .detect import (
     compiler_from_language,
diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index 3d3e57e..ea49833 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -84,6 +84,8 @@ for _l in clink_langs + ('vala',):
     clink_suffixes += lang_suffixes[_l]
 clink_suffixes += ('h', 'll', 's')
 all_suffixes = set(itertools.chain(*lang_suffixes.values(), clink_suffixes))  # type: T.Set[str]
+SUFFIX_TO_LANG = dict(itertools.chain(*(
+    [(suffix, lang) for suffix in v] for lang, v in lang_suffixes.items()))) # type: T.Dict[str, str]
 
 # Languages that should use LDFLAGS arguments when linking.
 LANGUAGES_USING_LDFLAGS = {'objcpp', 'cpp', 'objc', 'c', 'fortran', 'd', 'cuda'}  # type: T.Set[str]