rust: Override the default MSVCRT when linking Rust and !rust together

mesonbuild/backend/ninjabackend.py

@@ -37,6 +37,7 @@
 from .. import compilers
 from ..arglist import CompilerArgs
 from ..compilers import Compiler
+from ..compilers.mixins.visualstudio import VisualStudioLikeCompiler
 from ..linkers import ArLinker, RSPFileSyntax
 from ..mesonlib import (
     File, LibType, MachineChoice, MesonException, OrderedSet, PerMachine,
@@ -1944,6 +1945,30 @@ def generate_rust_target(self, target: build.BuildTarget) -> None:
         args += output
         linkdirs = mesonlib.OrderedSet()
         external_deps = target.external_deps.copy()
+
+        # Have we already injected msvc-crt args?
+        # On non-windows targets treat this as if we've already injected them
+        # Also, if we don't have A C, C++, or Fortran compiler treat this as if we've already injected them
+        #
+        # We handle this here rather than in the rust compiler because in
+        # general we don't want to link rust targets to a non-default crt.
+        # However, because of the way that MSCRTs work you can only link to one
+        # per target, so if A links to the debug one, and B links to the normal
+        # one you can't link A and B. Rust is hardcoded to the default one,
+        # so if we compile C/C++ code and link against a non-default MSCRT then
+        # linking will fail. We can work around this by injecting MSCRT link
+        # arguments early in the rustc command line
+        # https://github.com/rust-lang/rust/issues/39016#issuecomment-853964918
+        comp = mesonlib.first((self.environment.coredata.compilers[target.for_machine].get(l) for l in ['c', 'cpp', 'fortran']),
+                              lambda x: x is not None and isinstance(x, VisualStudioLikeCompiler))
+        crt_args_injected = not (self.environment.machines[target.for_machine].is_windows() or comp is None)
+
+        buildtype = self.environment.coredata.options[OptionKey('buildtype')].value
+        try:
+            crt = self.environment.coredata.options[OptionKey('b_scrt')].value
+        except KeyError:
+            crt = 'fake'
+
         # TODO: we likely need to use verbatim to handle name_prefix and name_suffix
         for d in target.link_targets:
             linkdirs.add(d.subdir)
@@ -1957,7 +1982,14 @@ def generate_rust_target(self, target: build.BuildTarget) -> None:
                 d_name = self._get_rust_dependency_name(target, d)
                 args += ['--extern', '{}={}'.format(d_name, os.path.join(d.subdir, d.filename))]
                 project_deps.append(RustDep(d_name, self.rust_crates[d.name].order))
-            elif isinstance(d, build.StaticLibrary):
+                continue
+
+            if not crt_args_injected and not {'c', 'cpp', 'fortran'}.isdisjoint(d.compilers):
+                for larg in comp.get_crt_link_args(crt, buildtype):
+                    args += ['-C', f'link-arg={larg}']
+                crt_args_injected = True
+
+            if isinstance(d, build.StaticLibrary):
                 # Rustc doesn't follow Meson's convention that static libraries
                 # are called .a, and import libraries are .lib, so we have to
                 # manually handle that.
@@ -1997,6 +2029,11 @@ def generate_rust_target(self, target: build.BuildTarget) -> None:
                 args += ['--extern', '{}={}'.format(d_name, os.path.join(d.subdir, d.filename))]
                 project_deps.append(RustDep(d_name, self.rust_crates[d.name].order))
             else:
+                if not crt_args_injected and not {'c', 'cpp', 'fortran'}.isdisjoint(d.compilers):
+                    for larg in comp.get_crt_link_args(crt, buildtype):
+                        args += ['-C', f'link-arg={larg}']
+                    crt_args_injected = True
+
                 if rustc.linker.id in {'link', 'lld-link'}:
                     if verbatim:
                         # If we can use the verbatim modifier, then everything is great