Add support for the CompCert C Compiler

* Add preliminary support for the CompCert C Compiler

The intention is to use this with the picolibc, so some GCC flags are
automatically filtered. Since CompCert uses GCC is for linking, those
GCC-linker flags which are used by picolibc, are automatically prefixed
with '-WUl', so that they're passed to GCC.

Squashed commit of the following:

commit 4e0ad66dca9de301d2e41e74aea4142afbd1da7d
Author: Sebastian Meyer <meyer@absint.com>
Date:   Mon Aug 31 14:20:39 2020 +0200

    remove '-fall' from default arguments, also filter -ftls-model=.*

commit 41afa3ccc62ae72824eb319cb8b34b7e6693cb67
Author: Sebastian Meyer <meyer@absint.com>
Date:   Mon Aug 31 14:13:55 2020 +0200

    use regex for filtering ccomp args

commit d68d242d0ad22f8bf53923ce849da9b86b696a75
Author: Sebastian Meyer <meyer@absint.com>
Date:   Mon Aug 31 13:54:36 2020 +0200

    filter some gcc arguments

commit 982a01756266bddbbd211c54e8dbfa2f43dec38f
Author: Sebastian Meyer <meyer@absint.com>
Date:   Fri Aug 28 15:03:14 2020 +0200

    fix ccomp meson configuration

commit dce0bea00b1caa094b1ed0c6c77cf6c12f0f58d9
Author: Sebastian Meyer <meyer@absint.com>
Date:   Thu Aug 27 13:02:19 2020 +0200

    add CompCert to meson (does not fully work, yet)

* remove unused import and s/cls/self/

fixes the two obvious LGTM warnings

* CompCert: Do not ignore unsupported GCC flags

Some are safe to ignore, however, as per
https://github.com/mesonbuild/meson/pull/7674, they should not be
ignored by meson itself. Instead the meson.build should take care to
select only those which are actually supported by the compiler.

* remove unused variable

* Only add arguments once.

* Apply suggestions from code review

Co-authored-by: Dylan Baker <dylan@pnwbakers.com>

* Remove erroneous ' ' from '-o {}'.format()

As noticed by @dcbaker

* added release note snippet for compcert

* properly split parameters

As suggested by @dcbaker, these parameters should be properly split into multiple strings.

Co-authored-by: Dylan Baker <dylan@pnwbakers.com>

* Update add_compcert_compiler.md

Added a sentence about the state of the implementation (experimental); use proper markdown

* properly separate arguments

Co-authored-by: Dylan Baker <dylan@pnwbakers.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/mesonbuild/environment.py b/mesonbuild/environment.py
index 97ed23c..4623049 100644
--- a/mesonbuild/environment.py
+++ b/mesonbuild/environment.py
@@ -19,7 +19,7 @@ import typing as T
 import collections
 
 from . import coredata
-from .linkers import ArLinker, ArmarLinker, VisualStudioLinker, DLinker, CcrxLinker, Xc16Linker, C2000Linker, IntelVisualStudioLinker, AIXArLinker
+from .linkers import ArLinker, ArmarLinker, VisualStudioLinker, DLinker, CcrxLinker, Xc16Linker, CompCertLinker, C2000Linker, IntelVisualStudioLinker, AIXArLinker
 from . import mesonlib
 from .mesonlib import (
     MesonException, EnvironmentException, MachineChoice, Popen_safe,
@@ -49,6 +49,7 @@ from .linkers import (
     ArmDynamicLinker,
     CcrxDynamicLinker,
     Xc16DynamicLinker,
+    CompCertDynamicLinker,
     C2000DynamicLinker,
     ClangClDynamicLinker,
     DynamicLinker,
@@ -120,6 +121,7 @@ from .compilers import (
     CcrxCCompiler,
     CcrxCPPCompiler,
     Xc16CCompiler,
+    CompCertCCompiler,
     C2000CCompiler,
     C2000CPPCompiler,
     SunFortranCompiler,
@@ -1155,6 +1157,8 @@ class Environment:
                 arg = '-v'
             elif 'xc16' in compiler_name:
                 arg = '--version'
+            elif 'ccomp' in compiler_name:
+                arg = '-version'
             elif 'cl2000' in compiler_name:
                 arg = '-version'
             elif compiler_name in {'icl', 'icl.exe'}:
@@ -1365,6 +1369,14 @@ class Environment:
                     ccache + compiler, version, for_machine, is_cross, info,
                     exe_wrap, full_version=full_version, linker=linker)
 
+            if 'CompCert' in out:
+                cls = CompCertCCompiler
+                self.coredata.add_lang_args(cls.language, cls, for_machine, self)
+                linker = CompCertDynamicLinker(for_machine, version=version)
+                return cls(
+                    ccache + compiler, version, for_machine, is_cross, info,
+                    exe_wrap, full_version=full_version, linker=linker)
+
             if 'TMS320C2000 C/C++' in out:
                 cls = C2000CCompiler if lang == 'c' else C2000CPPCompiler
                 self.coredata.add_lang_args(cls.language, cls, for_machine, self)
@@ -1373,6 +1385,7 @@ class Environment:
                     ccache + compiler, version, for_machine, is_cross, info,
                     exe_wrap, full_version=full_version, linker=linker)
 
+
         self._handle_exceptions(popen_exceptions, compilers)
 
     def detect_c_compiler(self, for_machine):
@@ -1965,6 +1978,8 @@ class Environment:
                 return Xc16Linker(linker)
             if out.startswith('TMS320C2000') and ('ar2000' in linker or 'ar2000.exe' in linker):
                 return C2000Linker(linker)
+            if out.startswith('The CompCert'):
+                return CompCertLinker(linker)
             if p.returncode == 0:
                 return ArLinker(linker)
             if p.returncode == 1 and err.startswith('usage'): # OSX