armltdclang: add support for ARM Ltd.'s `armclang` toolchain

This is another toolchain also called `armclang`, but it is not a cross
compiler like Keil's `armclang`. It is essentially the same as `clang`
based on its interface and CMake's support of the toolchain.

Use an `armltd` prefix for the compiler ID.

Fixes: #7255

docs/markdown/snippets/armclang-support.md

@@ -0,0 +1,6 @@
+## Support for ARM Ltd. Clang toolchain
+
+Support for the `armltdclang` compiler has been added. This differs from the
+existing `armclang` toolchain in that it is a fork of Clang by ARM Ltd. and
+supports native compilation. The Keil `armclang` toolchain only supports
+cross-compilation to embedded devices.

mesonbuild/compilers/c.py

@@ -183,6 +183,13 @@ class ClangCCompiler(_ClangCStds, ClangCompiler, CCompiler):
         return []
 
 
+class ArmLtdClangCCompiler(ClangCCompiler):
+
+    def __init__(self, *args, **kwargs):
+        ClangCCompiler.__init__(self, *args, **kwargs)
+        self.id = 'armltdclang'
+
+
 class AppleClangCCompiler(ClangCCompiler):
 
     """Handle the differences between Apple Clang and Vanilla Clang.

mesonbuild/compilers/cpp.py

@@ -155,7 +155,7 @@ class CPPCompiler(CLikeCompiler, Compiler):
         }
 
         # Currently, remapping is only supported for Clang, Elbrus and GCC
-        assert self.id in frozenset(['clang', 'lcc', 'gcc', 'emscripten'])
+        assert self.id in frozenset(['clang', 'lcc', 'gcc', 'emscripten', 'armltdclang'])
 
         if cpp_std not in CPP_FALLBACKS:
             # 'c++03' and 'c++98' don't have fallback types
@@ -259,6 +259,12 @@ class ClangCPPCompiler(ClangCompiler, CPPCompiler):
         return search_dirs + ['-lstdc++']
 
 
+class ArmLtdClangCPPCompiler(ClangCPPCompiler):
+    def __init__(self, *args, **kwargs):
+        ClangCPPCompiler.__init__(self, *args, **kwargs)
+        self.id = 'armltdclang'
+
+
 class AppleClangCPPCompiler(ClangCPPCompiler):
     def language_stdlib_only_link_flags(self, env: 'Environment') -> T.List[str]:
         # We need to apply the search prefix here, as these link arguments may

mesonbuild/compilers/detect.py

@@ -54,6 +54,7 @@ from .c import (
     AppleClangCCompiler,
     ArmCCompiler,
     ArmclangCCompiler,
+    ArmLtdClangCCompiler,
     ClangCCompiler,
     ClangClCCompiler,
     GnuCCompiler,
@@ -74,6 +75,7 @@ from .cpp import (
     AppleClangCPPCompiler,
     ArmCPPCompiler,
     ArmclangCPPCompiler,
+    ArmLtdClangCPPCompiler,
     ClangCPPCompiler,
     ClangClCPPCompiler,
     GnuCPPCompiler,
@@ -97,6 +99,7 @@ from .d import (
 from .cuda import CudaCompiler
 from .fortran import (
     FortranCompiler,
+    ArmLtdFlangFortranCompiler,
     G95FortranCompiler,
     GnuFortranCompiler,
     ElbrusFortranCompiler,
@@ -462,6 +465,20 @@ def _detect_c_or_cpp_compiler(env: 'Environment', lang: str, for_machine: Machin
                 ccache + compiler, version, for_machine, is_cross, info,
                 exe_wrap, linker=linker, full_version=full_version)
 
+        if 'Arm C/C++/Fortran Compiler' in out:
+            arm_ver_match = re.search('version (\d+)\.(\d+) \(build number (\d+)\)', out)
+            arm_ver_major = arm_ver_match.group(1)
+            arm_ver_minor = arm_ver_match.group(2)
+            arm_ver_build = arm_ver_match.group(3)
+            version = '.'.join([arm_ver_major, arm_ver_minor, arm_ver_build])
+            if lang == 'c':
+                cls = ArmLtdClangCCompiler
+            elif lang == 'cpp':
+                cls = ArmLtdClangCPPCompiler
+            linker = guess_nix_linker(env, compiler, cls, for_machine)
+            return cls(
+                ccache + compiler, version, for_machine, is_cross, info,
+                exe_wrap, linker=linker)
         if 'armclang' in out:
             # The compiler version is not present in the first line of output,
             # instead it is present in second line, startswith 'Component:'.
@@ -711,6 +728,17 @@ def detect_fortran_compiler(env: 'Environment', for_machine: MachineChoice) -> C
                         compiler, version, for_machine, is_cross, info,
                         exe_wrap, defines, full_version=full_version, linker=linker)
 
+            if 'Arm C/C++/Fortran Compiler' in out:
+                cls = ArmLtdFlangFortranCompiler
+                arm_ver_match = re.search('version (\d+)\.(\d+) \(build number (\d+)\)', out)
+                arm_ver_major = arm_ver_match.group(1)
+                arm_ver_minor = arm_ver_match.group(2)
+                arm_ver_build = arm_ver_match.group(3)
+                version = '.'.join([arm_ver_major, arm_ver_minor, arm_ver_build])
+                linker = guess_nix_linker(env, compiler, cls, for_machine)
+                return cls(
+                    ccache + compiler, version, for_machine, is_cross, info,
+                    exe_wrap, linker=linker)
             if 'G95' in out:
                 cls = G95FortranCompiler
                 linker = guess_nix_linker(env, compiler, cls, for_machine)

mesonbuild/compilers/fortran.py

@@ -494,6 +494,12 @@ class FlangFortranCompiler(ClangCompiler, FortranCompiler):
                 search_dirs.append(f'-L{d}')
         return search_dirs + ['-lflang', '-lpgmath']
 
+class ArmLtdFlangFortranCompiler(FlangFortranCompiler):
+
+    def __init__(self, *args, **kwargs):
+        FlangFortranCompiler.__init__(self, *args, **kwargs)
+        self.id = 'armltdflang'
+
 class Open64FortranCompiler(FortranCompiler):
 
     def __init__(self, exelist: T.List[str], version: str, for_machine: MachineChoice, is_cross: bool,