compilers: Move lto args into compiler class

There are two problems, one is that it assumes -flto is the argument
to do LTO/WPO, which isn't true of ICC and MSVC (and presumably)
others. It's also incorrect because it assumes that the compiler and
linker will always be the same, which isn't necessarily true. You
could combine GCC with Apple's linker, or clang with link.exe, which
use different arguments.

2 files changed, 15 insertions, 5 deletions

diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index df448f0..4ab4dc6 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import contextlib, enum, os.path, re, tempfile, shlex
-from typing import Optional, Tuple
+from typing import Optional, Tuple, List
 
 from ..linkers import StaticLinker
 from .. import coredata
@@ -278,10 +278,9 @@ def option_enabled(boptions, options, option):
 
 def get_base_compile_args(options, compiler):
     args = []
-    # FIXME, gcc/clang specific.
     try:
         if options['b_lto'].value:
-            args.append('-flto')
+            args.extend(compiler.get_lto_compile_args())
     except KeyError:
         pass
     try:
@@ -328,10 +327,9 @@ def get_base_compile_args(options, compiler):
 
 def get_base_link_args(options, linker, is_shared_module):
     args = []
-    # FIXME, gcc/clang specific.
     try:
         if options['b_lto'].value:
-            args.append('-flto')
+            args.extend(linker.get_lto_link_args())
     except KeyError:
         pass
     try:
@@ -1197,6 +1195,12 @@ class Compiler:
     def remove_linkerlike_args(self, args):
         return [x for x in args if not x.startswith('-Wl')]
 
+    def get_lto_compile_args(self) -> List[str]:
+        return []
+
+    def get_lto_link_args(self) -> List[str]:
+        return []
+
 
 @enum.unique
 class CompilerType(enum.Enum):
diff --git a/mesonbuild/compilers/mixins/gnu.py b/mesonbuild/compilers/mixins/gnu.py
index 46f04c4..c575045 100644
--- a/mesonbuild/compilers/mixins/gnu.py
+++ b/mesonbuild/compilers/mixins/gnu.py
@@ -366,6 +366,12 @@ class GnuLikeCompiler(metaclass=abc.ABCMeta):
                 return self._split_fetch_real_dirs(line.split('=', 1)[1])
         return []
 
+    def get_lto_compile_args(self) -> typing.List[str]:
+        return ['-flto']
+
+    def get_lto_link_args(self) -> typing.List[str]:
+        return ['-flto']
+
 
 class GnuCompiler(GnuLikeCompiler):
     """