uniform scan-build detection process

Detect scan-build the same way when trying to launch it and when
generating the target.
The detection method is:
  1. look within SCANBUILD env variable
  2. shutil.which('scan-build')
  3. *on non-linux platforms only*: go through all the possible
     name candidates and test them individually.

The third step is added following this comment
https://github.com/mesonbuild/meson/pull/5857#issuecomment-528305788
However, going through a list of all the possible candidates is neither
easily maintainable nor performant, and is therefore skipped on
platforms that should not require such a step (currently, only Linux
platforms).

This is a follow-up to the issue raised by @lantw44 during PR:
https://github.com/mesonbuild/meson/pull/5857

mesonbuild/backend/ninjabackend.py

@@ -2646,8 +2646,7 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
         self.create_target_alias('meson-dist')
 
     def generate_scanbuild(self):
-        import shutil
-        if shutil.which('scan-build') is None:
+        if not environment.detect_scanbuild():
             return
         cmd = self.environment.get_build_command() + \
             ['--internal', 'scanbuild', self.environment.source_dir, self.environment.build_dir] + \

mesonbuild/environment.py

@@ -163,6 +163,55 @@ def detect_ninja(version: str = '1.5', log: bool = False) -> str:
                 mlog.log('Found {}-{} at {}'.format(name, found, quote_arg(n)))
             return n
 
+def detect_scanbuild():
+    """ Look for scan-build binary on build platform
+
+    First, if a SCANBUILD env variable has been provided, give it precedence
+    on all platforms.
+
+    For most platforms, scan-build is found is the PATH contains a binary
+    named "scan-build". However, some distribution's package manager (FreeBSD)
+    don't. For those, loop through a list of candidates to see if one is
+    available.
+    Since this is a costly operation, limit it to the impacted platforms
+    (currently all non-linux platforms)
+
+    Return: a single-element list of the found scan-build binary ready to be
+        passed to Popen()
+    """
+    exelist = []
+    if 'SCANBUILD' in os.environ:
+        exelist = split_args(os.environ['SCANBUILD'])
+
+    elif shutil.which('scan-build') is not None:
+        exelist = [shutil.which('scan-build')]
+
+    elif platform.system() != 'Linux':
+        tools = [
+            'scan-build',  # base
+            'scan-build-8.0', 'scan-build80',
+            'scan-build-7.0', 'scan-build70',
+            'scan-build-6.0', 'scan-build60',
+            'scan-build-5.0', 'scan-build50',
+            'scan-build-4.0', 'scan-build40',
+            'scan-build-3.9', 'scan-build39',
+            'scan-build-3.8', 'scan-build38',
+            'scan-build-3.7', 'scan-build37',
+            'scan-build-3.6', 'scan-build36',
+            'scan-build-3.5', 'scan-build35',
+            'scan-build-9.0', 'scan-build-devel',  # development snapshot
+        ]
+        for tool in tools:
+            if shutil.which(tool) is not None:
+                exelist = [shutil.which(tool)]
+                break
+
+    if exelist:
+        tool = exelist[0]
+        if os.path.isfile(tool) and os.access(tool, os.X_OK):
+            return [tool]
+    return []
+
 def detect_native_windows_arch():
     """
     The architecture of Windows itself: x86, amd64 or arm64
@@ -745,7 +794,7 @@ class Environment:
             else:
                 i = 'GNU ld.bfd'
             linker = GnuDynamicLinker(compiler, for_machine, i, prefix, version=v)
-        elif 'Solaris' in e:
+        elif 'Solaris' in e or 'Solaris' in o:
             linker = SolarisDynamicLinker(
                 compiler, for_machine, 'solaris', prefix,
                 version=search_version(e))

mesonbuild/mesonlib.py

@@ -708,6 +708,14 @@ def get_library_dirs() -> typing.List[str]:
     else:
         plat = ''
 
+    # Solaris puts 32-bit libraries in the main /lib & /usr/lib directories
+    # and 64-bit libraries in platform specific subdirectories.
+    if is_sunos():
+        if machine == 'i86pc':
+            plat = 'amd64'
+        elif machine.startswith('sun4'):
+            plat = 'sparcv9'
+
     usr_platdir = Path('/usr/lib/') / plat
     if usr_platdir.is_dir():
         unixdirs += [str(x) for x in (usr_platdir).iterdir() if x.is_dir()]

mesonbuild/scripts/scanbuild.py

@@ -16,9 +16,10 @@ import os
 import subprocess
 import shutil
 import tempfile
-from ..environment import detect_ninja
+from ..environment import detect_ninja, detect_scanbuild
 from ..mesonlib import Popen_safe, split_args
 
+
 def scanbuild(exelist, srcdir, blddir, privdir, logdir, args):
     with tempfile.TemporaryDirectory(dir=privdir) as scandir:
         meson_cmd = exelist + args
@@ -28,6 +29,7 @@ def scanbuild(exelist, srcdir, blddir, privdir, logdir, args):
             return rc
         return subprocess.call(build_cmd)
 
+
 def run(args):
     srcdir = args[0]
     blddir = args[1]
@@ -35,40 +37,10 @@ def run(args):
     privdir = os.path.join(blddir, 'meson-private')
     logdir = os.path.join(blddir, 'meson-logs/scanbuild')
     shutil.rmtree(logdir, ignore_errors=True)
-    tools = [
-        'scan-build',  # base
-        'scan-build-8.0', 'scan-build80',
-        'scan-build-7.0', 'scan-build70',
-        'scan-build-6.0', 'scan-build60',
-        'scan-build-5.0', 'scan-build50',
-        'scan-build-4.0', 'scan-build40',
-        'scan-build-3.9', 'scan-build39',
-        'scan-build-3.8', 'scan-build38',
-        'scan-build-3.7', 'scan-build37',
-        'scan-build-3.6', 'scan-build36',
-        'scan-build-3.5', 'scan-build35',
-        'scan-build-9.0', 'scan-build-devel',  # development snapshot
-    ]
-    toolname = 'scan-build'
-    for tool in tools:
-        try:
-            p, out = Popen_safe([tool, '--help'])[:2]
-        except (FileNotFoundError, PermissionError):
-            continue
-        if p.returncode != 0:
-            continue
-        else:
-            toolname = tool
-            break
 
-    if 'SCANBUILD' in os.environ:
-        exelist = split_args(os.environ['SCANBUILD'])
-    else:
-        exelist = [toolname]
-
-    try:
-        Popen_safe(exelist + ['--help'])
-    except OSError:
+    exelist = detect_scanbuild()
+    if not exelist:
         print('Could not execute scan-build "%s"' % ' '.join(exelist))
         return 1
+
     return scanbuild(exelist, srcdir, blddir, privdir, logdir, meson_cmd)

test cases/common/131 generated assembly/square-x86_64.S.in

@@ -19,7 +19,7 @@ END
 .text
 .globl SYMBOL_NAME(square_unsigned)
 /* Only supported with GAS */
-# if defined(__linux__) || defined(__DragonFly__) || defined(__FreeBSD__) || defined(__NetBSD__)
+# if defined(__linux__) || defined(__DragonFly__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__sun)
 .type  square_unsigned,@function
 # endif
 

test cases/linuxlike/14 static dynamic linkage/meson.build

@@ -1,22 +1,36 @@
 project('static dynamic', 'c')
 
+# Solaris does not ship static libraries
+if host_machine.system() == 'sunos'
+  has_static = false
+else
+  has_static = true
+endif
 
 cc = meson.get_compiler('c')
 
 z_default = cc.find_library('z')
-z_static = cc.find_library('z', static: true)
+if has_static
+  z_static = cc.find_library('z', static: true)
+endif
 z_dynamic = cc.find_library('z', static: false)
 
 exe_default = executable('main_default', 'main.c', dependencies: [z_default])
-exe_static = executable('main_static', 'main.c', dependencies: [z_static])
+if has_static
+  exe_static = executable('main_static', 'main.c', dependencies: [z_static])
+endif
 exe_dynamic = executable('main_dynamic', 'main.c', dependencies: [z_dynamic])
 
 test('test default', exe_default)
-test('test static', exe_static)
+if has_static
+  test('test static', exe_static)
+endif
 test('test dynamic', exe_dynamic)
 
-test('verify static linking', find_program('verify_static.py'),
-    args: ['--platform=' + host_machine.system(), exe_static.full_path()])
+if has_static
+  test('verify static linking', find_program('verify_static.py'),
+      args: ['--platform=' + host_machine.system(), exe_static.full_path()])
+endif
 test('verify dynamic linking', find_program('verify_static.py'),
     args: ['--platform=' + host_machine.system(), exe_dynamic.full_path()],
     should_fail: true)