compilers: Try harder to dedup builtin libs

Compiler internal libs should always be de-duplicated, no matter what.

Closes https://github.com/mesonbuild/meson/issues/2150

Test case is by Bruce Richardson in the issue.

mesonbuild/compilers/c.py

@@ -35,6 +35,7 @@ from .compilers import (
     get_largefile_args,
     gnu_winlibs,
     msvc_winlibs,
+    unixy_compiler_internal_libs,
     vs32_instruction_set_args,
     vs64_instruction_set_args,
     ArmCompiler,
@@ -52,8 +53,6 @@ from .compilers import (
     CcrxCompiler,
 )
 
-gnu_compiler_internal_libs = ('m', 'c', 'pthread', 'dl', 'rt')
-
 
 class CCompiler(Compiler):
     # TODO: Replace this manual cache with functools.lru_cache
@@ -61,7 +60,7 @@ class CCompiler(Compiler):
     program_dirs_cache = {}
     find_library_cache = {}
     find_framework_cache = {}
-    internal_libs = gnu_compiler_internal_libs
+    internal_libs = unixy_compiler_internal_libs
 
     @staticmethod
     def attribute_check_func(name):
@@ -1375,7 +1374,7 @@ class IntelCCompiler(IntelCompiler, CCompiler):
 class VisualStudioCCompiler(CCompiler):
     std_warn_args = ['/W3']
     std_opt_args = ['/O2']
-    ignore_libs = gnu_compiler_internal_libs
+    ignore_libs = unixy_compiler_internal_libs
     internal_libs = ()
 
     crt_args = {'none': [],

mesonbuild/compilers/compilers.py

@@ -81,6 +81,9 @@ cflags_mapping = {'c': 'CFLAGS',
                   'vala': 'VALAFLAGS',
                   'rust': 'RUSTFLAGS'}
 
+# execinfo is a compiler lib on BSD
+unixy_compiler_internal_libs = ('m', 'c', 'pthread', 'dl', 'rt', 'execinfo')
+
 # All these are only for C-linkable languages; see `clink_langs` above.
 
 def sort_clink(lang):
@@ -659,6 +662,9 @@ class CompilerArgs(list):
     # Only UNIX shared libraries require this. Others have a fixed extension.
     dedup1_regex = re.compile(r'([\/\\]|\A)lib.*\.so(\.[0-9]+)?(\.[0-9]+)?(\.[0-9]+)?$')
     dedup1_args = ('-c', '-S', '-E', '-pipe', '-pthread')
+    # In generate_link() we add external libs without de-dup, but we must
+    # *always* de-dup these because they're special arguments to the linker
+    always_dedup_args = tuple('-l' + lib for lib in unixy_compiler_internal_libs)
     compiler = None
 
     def _check_args(self, args):
@@ -793,7 +799,7 @@ class CompilerArgs(list):
         normal_flags = []
         lflags = []
         for i in iterable:
-            if i.startswith('-l') or i.startswith('-L'):
+            if i not in self.always_dedup_args and (i.startswith('-l') or i.startswith('-L')):
                 lflags.append(i)
             else:
                 normal_flags.append(i)

run_unittests.py

@@ -3893,7 +3893,7 @@ class WindowsTests(BasePlatformTests):
         if cc.get_argument_syntax() != 'msvc':
             raise unittest.SkipTest('Not using MSVC')
         # To force people to update this test, and also test
-        self.assertEqual(set(cc.ignore_libs), {'c', 'm', 'pthread', 'dl', 'rt'})
+        self.assertEqual(set(cc.ignore_libs), {'c', 'm', 'pthread', 'dl', 'rt', 'execinfo'})
         for l in cc.ignore_libs:
             self.assertEqual(cc.find_library(l, env, []), [])
 
@@ -5043,6 +5043,19 @@ endian = 'little'
                 max_count = max(max_count, line.count(search_term))
         self.assertEqual(max_count, 1, 'Export dynamic incorrectly deduplicated.')
 
+    def test_compiler_libs_static_dedup(self):
+        testdir = os.path.join(self.unit_test_dir, '55 dedup compiler libs')
+        self.init(testdir)
+        build_ninja = os.path.join(self.builddir, 'build.ninja')
+        with open(build_ninja, 'r', encoding='utf-8') as f:
+            lines = f.readlines()
+        for lib in ('-ldl', '-lm', '-lc', '-lrt'):
+            for line in lines:
+                if lib not in line:
+                    continue
+                # Assert that
+                self.assertEqual(len(line.split(lib)), 2, msg=(lib, line))
+
 
 def should_run_cross_arm_tests():
     return shutil.which('arm-linux-gnueabihf-gcc') and not platform.machine().lower().startswith('arm')

test cases/unit/55 dedup compiler libs/app/app.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <liba.h>
+#include <libb.h>
+
+int
+main(void)
+{
+  printf("start value = %d\n", liba_get());
+  liba_add(2);
+  libb_mul(5);
+  printf("end value = %d\n", liba_get());
+  return 0;
+}

test cases/unit/55 dedup compiler libs/app/meson.build

@@ -0,0 +1,2 @@
+executable('app', 'app.c',
+  dependencies: [liba_dep, libb_dep])

test cases/unit/55 dedup compiler libs/liba/liba.c

@@ -0,0 +1,18 @@
+#include "liba.h"
+
+static int val;
+
+void liba_add(int x)
+{
+  val += x;
+}
+
+void liba_sub(int x)
+{
+  val -= x;
+}
+
+int liba_get(void)
+{
+  return val;
+}

test cases/unit/55 dedup compiler libs/liba/liba.h

@@ -0,0 +1,8 @@
+#ifndef LIBA_H_
+#define LIBA_H_
+
+void liba_add(int x);
+void liba_sub(int x);
+int liba_get(void);
+
+#endif

test cases/unit/55 dedup compiler libs/liba/meson.build

@@ -0,0 +1,8 @@
+deps = [dependency('threads'), cc.find_library('dl'), cc.find_library('m')]
+
+liba = library('a', 'liba.c',
+  dependencies: deps)
+
+liba_dep = declare_dependency(link_with: liba,
+  include_directories: include_directories('.'),
+  dependencies: deps)

test cases/unit/55 dedup compiler libs/libb/libb.c

@@ -0,0 +1,7 @@
+#include <liba.h>
+#include "libb.h"
+
+void libb_mul(int x)
+{
+  liba_add(liba_get() * (x - 1));
+}

test cases/unit/55 dedup compiler libs/libb/libb.h

@@ -0,0 +1,6 @@
+#ifndef _LIBB_H_
+#define _LIBB_H_
+
+void libb_mul(int x);
+
+#endif

test cases/unit/55 dedup compiler libs/libb/meson.build

@@ -0,0 +1,6 @@
+libb = library('b', 'libb.c',
+  dependencies: liba_dep)
+
+libb_dep = declare_dependency(link_with: libb,
+  include_directories: include_directories('.'),
+  dependencies: liba_dep)

test cases/unit/55 dedup compiler libs/meson.build

@@ -0,0 +1,7 @@
+project('temp', 'c')
+
+cc = meson.get_compiler('c')
+
+subdir('liba')
+subdir('libb')
+subdir('app')