Get include directories for CC-like compilers if possible

This also lets us avoid unnecessarily passing default include directories on
the command line.

CHANGES.md

@@ -5,6 +5,7 @@
 ### Bug fixes
 - When using the `PKG_CONFIG_PATH` specified by mopack, add it to any existing
   `PKG_CONFIG_PATH` from the environment
+- Don't explicitly include default `#include` paths on CC-like compilers
 
 ---
 

bfg9000/tools/cc/compiler.py

@@ -1,11 +1,12 @@
 from itertools import chain
 
-from ... import options as opts, safe_str
+from ... import options as opts, safe_str, shell
 from .flags import optimize_flags
 from ..common import BuildCommand
 from ...file_types import ObjectFile, PrecompiledHeader
-from ...iterutils import iterate
-from ...path import Path
+from ...iterutils import default_sentinel, iterate
+from ...objutils import memoize_method
+from ...path import abspath, Path
 from ...versioning import SpecifierSet
 
 
@@ -22,8 +23,37 @@ def needs_libs(self):
     def needs_package_options(self):
         return True
 
+    @memoize_method
+    def _search_dirs(self, cpath=default_sentinel, strict=False):
+        try:
+            extra_env = ({'CPATH': cpath or ''}
+                         if cpath is not default_sentinel else None)
+            output = self.env.execute(
+                (self.command + self._always_flags + self.global_flags +
+                 ['-E', '-Wp,-v', '/dev/null']),
+                extra_env=extra_env, stdout=shell.Mode.pipe,
+                stderr=shell.Mode.stdout
+            )
+
+            found = False
+            dirs = []
+            for i in output.splitlines():  # pragma: no branch
+                if i == '#include <...> search starts here:':
+                    found = True
+                elif i == 'End of search list.':
+                    break
+                elif i[0] != ' ':
+                    found = False
+                elif found:
+                    dirs.append(abspath(i[1:]))
+            return dirs
+        except (OSError, shell.CalledProcessError):
+            if strict:
+                raise
+            return self.env.variables.getpaths('CPATH')
+
     def search_dirs(self, strict=False):
-        return self.env.variables.getpaths('CPATH')
+        return self._search_dirs(strict=strict)
 
     def _call(self, cmd, input, output, deps=None, flags=None):
         result = list(chain(
@@ -49,12 +79,14 @@ def _always_flags(self):
         return flags
 
     def _include_dir(self, directory, allow_system):
-        is_default = directory.path in self.env.host_platform.include_dirs
-
-        # Don't include default directories as system dirs (e.g. /usr/include).
-        # Doing so would break GCC 6 when #including stdlib.h:
-        # <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129>.
-        if allow_system and directory.system and not is_default:
+        default_dirs = self._search_dirs(None)
+        if directory.path in default_dirs:
+            # Don't include default directories (e.g. /usr/include). Including
+            # them as system dirs would break GCC 6 when #including stdlib.h:
+            # <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129>. Including
+            # them as regular directories isn't right either.
+            return []
+        elif allow_system and directory.system:
             return ['-isystem', directory.path]
         else:
             return ['-I' + directory.path]

bfg9000/tools/cc/linker.py

@@ -9,6 +9,7 @@
 from ...builtins.copy_file import CopyFile
 from ...file_types import *
 from ...iterutils import first, iterate, listify, recursive_walk, uniques
+from ...objutils import memoize_method
 from ...path import abspath, Path
 from ...versioning import SpecifierSet
 from ...packages import Framework
@@ -71,6 +72,7 @@ def _has_link_macros(self):
         # and only define the macros if it does.
         return self.env.target_platform.has_import_library
 
+    @memoize_method
     def sysroot(self, strict=False):
         try:
             # XXX: clang doesn't support -print-sysroot.
@@ -83,6 +85,7 @@ def sysroot(self, strict=False):
                 raise
             return '' if self.env.target_platform.family == 'windows' else '/'
 
+    @memoize_method
     def search_dirs(self, strict=False):
         try:
             output = self.env.execute(

doc/about/changes.md

@@ -7,6 +7,7 @@ in progress
 ### Bug fixes
 - When using the `PKG_CONFIG_PATH` specified by mopack, add it to any existing
   `PKG_CONFIG_PATH` from the environment
+- Don't explicitly include default `#include` paths on CC-like compilers
 
 ---
 

test/unit/tools/cc/test_compiler.py

@@ -1,3 +1,4 @@
+from textwrap import dedent
 from unittest import mock
 
 from ... import *
@@ -7,7 +8,7 @@
 from bfg9000.file_types import (HeaderDirectory, HeaderFile, ObjectFile,
                                 PrecompiledHeader, SourceFile)
 from bfg9000.tools.cc import CcBuilder
-from bfg9000.path import Path, Root
+from bfg9000.path import abspath, Path, Root
 
 
 class TestCcCompiler(CrossPlatformTestCase):
@@ -19,6 +20,7 @@ def setUp(self):
              mock.patch('bfg9000.shell.execute', mock_execute):
             self.compiler = CcBuilder(self.env, known_langs['c++'], ['c++'],
                                       True, 'version').compiler
+        self.compiler._search_dirs._reset(self.compiler)
 
     def test_call(self):
         extra = self.compiler._always_flags
@@ -49,24 +51,50 @@ def test_output_file(self):
         self.assertEqual(self.compiler.output_file('file', None),
                          ObjectFile(Path('file.o'), fmt, 'c++'))
 
+    def test_search_dirs(self):
+        def mock_execute(*args, **kwargs):
+            return dedent("""\
+             /bad/include
+            #include <...> search starts here:
+             /usr/include
+             /path/to/include
+            End of search list.
+            """)
+
+        dirs = [abspath('/usr/include'), abspath('/path/to/include')]
+        with mock.patch('bfg9000.shell.execute', mock_execute):
+            self.assertEqual(self.compiler.search_dirs(), dirs)
+            self.assertEqual(self.compiler.search_dirs(True), dirs)
+
+    def test_search_dirs_broken(self):
+        def mock_execute(*args, **kwargs):
+            raise OSError()
+
+        with mock.patch('bfg9000.shell.execute', mock_execute):
+            self.assertEqual(self.compiler.search_dirs(), [])
+            with self.assertRaises(OSError):
+                self.compiler.search_dirs(True)
+
     def test_flags_empty(self):
         self.assertEqual(self.compiler.flags(opts.option_list()), [])
 
     def test_flags_include_dir(self):
-        p = self.Path('/path/to/include')
-        self.assertEqual(self.compiler.flags(opts.option_list(
-            opts.include_dir(HeaderDirectory(p))
-        )), ['-I' + p])
+        search_dirs = 'bfg9000.tools.cc.compiler.CcBaseCompiler._search_dirs'
+        with mock.patch(search_dirs, lambda *args, **kwargs: []):
+            p = self.Path('/path/to/include')
+            self.assertEqual(self.compiler.flags(opts.option_list(
+                opts.include_dir(HeaderDirectory(p))
+            )), ['-I' + p])
 
-        self.assertEqual(self.compiler.flags(opts.option_list(
-            opts.include_dir(HeaderDirectory(p, system=True))
-        )), ['-isystem', p])
+            self.assertEqual(self.compiler.flags(opts.option_list(
+                opts.include_dir(HeaderDirectory(p, system=True))
+            )), ['-isystem', p])
 
-        if self.env.target_platform.genus == 'linux':
-            p = self.Path('/usr/include')
+        p = self.Path('/usr/include')
+        with mock.patch(search_dirs, lambda *args, **kwargs: [p]):
             self.assertEqual(self.compiler.flags(opts.option_list(
                 opts.include_dir(HeaderDirectory(p, system=True))
-            )), ['-I' + p])
+            )), [])
 
     def test_flags_define(self):
         self.assertEqual(self.compiler.flags(opts.option_list(

test/unit/tools/cc/test_linker.py

@@ -1,3 +1,4 @@
+from textwrap import dedent
 from unittest import mock
 
 from ... import *
@@ -9,7 +10,7 @@
 from bfg9000.file_types import *
 from bfg9000.tools.cc import CcBuilder
 from bfg9000.packages import Framework
-from bfg9000.path import InstallRoot, Path, Root
+from bfg9000.path import abspath, InstallRoot, Path, Root
 
 
 class TestCcLinker(CrossPlatformTestCase):
@@ -29,6 +30,8 @@ def _get_output_file(self):
 
     def setUp(self):
         self.linker = self._get_linker('c++')
+        self.linker.sysroot._reset(self.linker)
+        self.linker.search_dirs._reset(self.linker)
 
     def test_call(self):
         extra = self.linker._always_flags
@@ -68,6 +71,18 @@ def mock_execute(*args, **kwargs):
             self.linker.sysroot(True)
 
     def test_search_dirs(self):
+        def mock_execute(*args, **kwargs):
+            return dedent("""\
+            install: /usr/lib/gcc
+            libraries: =/usr/lib{}/path/to/lib
+            """.format(os.pathsep))
+
+        dirs = [abspath('/usr/lib'), abspath('/path/to/lib')]
+        with mock.patch('bfg9000.shell.execute', mock_execute):
+            self.assertEqual(self.linker.search_dirs(), dirs)
+            self.assertEqual(self.linker.search_dirs(True), dirs)
+
+    def test_search_dirs_broken(self):
         def mock_execute(*args, **kwargs):
             raise OSError()