Don't add dependencies recursively while linking

We were doing this on the basis of an old comment, but there was no
test for it and I couldn't reproduce the issue with clang on Linux
at all.

Let's add a (somewhat comprehensive) test and see if it breaks
anywhere if we stop doing this.

Halves the size of gstreamer's build.ninja from 20M to 8.7M

Closes https://github.com/mesonbuild/meson/issues/1057

mesonbuild/backend/backends.py

@@ -453,15 +453,11 @@ class Backend:
         for d in deps:
             if not isinstance(d, (build.StaticLibrary, build.SharedLibrary)):
                 raise RuntimeError('Tried to link with a non-library target "%s".' % d.get_basename())
-            if isinstance(compiler, compilers.LLVMDCompiler) or isinstance(compiler, compilers.DmdDCompiler):
-                args += ['-L' + self.get_target_filename_for_linking(d)]
+            if isinstance(compiler, (compilers.LLVMDCompiler, compilers.DmdDCompiler)):
+                d_arg = '-L' + self.get_target_filename_for_linking(d)
             else:
-                args.append(self.get_target_filename_for_linking(d))
-            # If you have executable e that links to shared lib s1 that links to shared library s2
-            # you have to specify s2 as well as s1 when linking e even if e does not directly use
-            # s2. Gcc handles this case fine but Clang does not for some reason. Thus we need to
-            # explictly specify all libraries every time.
-            args += self.build_target_link_arguments(compiler, d.get_dependencies())
+                d_arg = self.get_target_filename_for_linking(d)
+            args.append(d_arg)
         return args
 
     def determine_windows_extra_paths(self, target):

test cases/common/153 recursive linking/3rdorderdeps/lib.c.in

@@ -0,0 +1,8 @@
+#include "../lib.h"
+
+int get_@DEPENDENCY@dep_value (void);
+
+SYMBOL_EXPORT
+int get_@LIBTYPE@@DEPENDENCY@dep_value (void) {
+  return get_@DEPENDENCY@dep_value ();
+}

test cases/common/153 recursive linking/3rdorderdeps/main.c.in

@@ -0,0 +1,16 @@
+#include <stdio.h>
+
+#include "../lib.h"
+
+SYMBOL_IMPORT int get_@LIBTYPE@@DEPENDENCY@dep_value (void);
+
+int main(int argc, char *argv[]) {
+  int val;
+
+  val = get_@LIBTYPE@@DEPENDENCY@dep_value ();
+  if (val != @VALUE@) {
+    printf("@LIBTYPE@@DEPENDENCY@ was %i instead of @VALUE@\n", val);
+    return -1;
+  }
+  return 0;
+}

test cases/common/153 recursive linking/3rdorderdeps/meson.build

@@ -0,0 +1,44 @@
+dep3_libs = []
+
+# Permutate all combinations of shared and static libraries up to three levels
+# executable -> shared -> static -> shared (etc)
+foreach dep2 : ['sh', 'st']
+  foreach dep1 : ['sh', 'st']
+    foreach libtype : ['sh', 'st']
+      name = libtype + dep1 + dep2
+      if dep2 == 'sh'
+        libret = 1
+      elif dep2 == 'st'
+        libret = 2
+      else
+        error('Unknown dep2 "@0@"'.format(dep2))
+      endif
+
+      if libtype == 'sh'
+        target = 'shared_library'
+      elif libtype == 'st'
+        target = 'static_library'
+      else
+        error('Unknown libtype "@0@"'.format(libtype))
+      endif
+
+      cdata = configuration_data()
+      cdata.set('DEPENDENCY', dep1 + dep2)
+      cdata.set('LIBTYPE', libtype)
+      cdata.set('VALUE', libret)
+
+      lib_c = configure_file(input : 'lib.c.in',
+                             output : name + '-lib.c',
+                             configuration : cdata)
+      dep = get_variable(dep1 + dep2 + 'dep')
+      dep3_lib = build_target(name, lib_c, link_with : dep, target_type : target)
+      dep3_libs += [dep3_lib]
+
+      main_c = configure_file(input : 'main.c.in',
+                              output : name + '-main.c',
+                              configuration : cdata)
+      dep3_bin = executable(name, main_c, link_with : dep3_lib)
+      test(name + 'test', dep3_bin)
+    endforeach
+  endforeach
+endforeach

test cases/common/153 recursive linking/lib.h

@@ -0,0 +1,12 @@
+#if defined _WIN32
+  #define SYMBOL_IMPORT __declspec(dllimport)
+  #define SYMBOL_EXPORT __declspec(dllexport)
+#else
+  #define SYMBOL_IMPORT
+  #if defined __GNUC__
+    #define SYMBOL_EXPORT __attribute__ ((visibility("default")))
+  #else
+    #pragma message ("Compiler does not support symbol visibility.")
+    #define SYMBOL_EXPORT
+  #endif
+#endif

test cases/common/153 recursive linking/main.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+
+#include "lib.h"
+
+SYMBOL_IMPORT int get_stnodep_value (void);
+SYMBOL_IMPORT int get_shnodep_value (void);
+SYMBOL_IMPORT int get_shshdep_value (void);
+SYMBOL_IMPORT int get_shstdep_value (void);
+SYMBOL_IMPORT int get_stshdep_value (void);
+SYMBOL_IMPORT int get_ststdep_value (void);
+
+int main(int argc, char *argv[]) {
+  int val;
+
+  val = get_shnodep_value ();
+  if (val != 1) {
+    printf("shnodep was %i instead of 1\n", val);
+    return -1;
+  }
+  val = get_stnodep_value ();
+  if (val != 2) {
+    printf("stnodep was %i instead of 2\n", val);
+    return -2;
+  }
+  val = get_shshdep_value ();
+  if (val != 1) {
+    printf("shshdep was %i instead of 1\n", val);
+    return -3;
+  }
+  val = get_shstdep_value ();
+  if (val != 2) {
+    printf("shstdep was %i instead of 2\n", val);
+    return -4;
+  }
+  val = get_stshdep_value ();
+  if (val != 1) {
+    printf("shstdep was %i instead of 1\n", val);
+    return -5;
+  }
+  val = get_ststdep_value ();
+  if (val != 2) {
+    printf("ststdep was %i instead of 2\n", val);
+    return -6;
+  }
+  return 0;
+}

test cases/common/153 recursive linking/meson.build

@@ -0,0 +1,22 @@
+project('recursive dependencies', 'c')
+
+# Test that you can link a shared executable to:
+# - A shared library with no other deps
+subdir('shnodep')
+# - A static library with no other deps
+subdir('stnodep')
+# - A shared library with a shared library dep
+subdir('shshdep')
+# - A shared library with a static library dep
+subdir('shstdep')
+# - A static library with a shared library dep
+subdir('stshdep')
+# - A static library with a static library dep
+subdir('ststdep')
+
+test('alldeps',
+     executable('alldeps', 'main.c',
+                link_with : [shshdep, shstdep, ststdep, stshdep]))
+
+# More combinations of static and shared libraries
+subdir('3rdorderdeps')

test cases/common/153 recursive linking/shnodep/lib.c

@@ -0,0 +1,6 @@
+#include "../lib.h"
+
+SYMBOL_EXPORT
+int get_shnodep_value (void) {
+  return 1;
+}

test cases/common/153 recursive linking/shnodep/meson.build

@@ -0,0 +1 @@
+shnodep = shared_library('shnodep', 'lib.c')

test cases/common/153 recursive linking/shshdep/lib.c

@@ -0,0 +1,8 @@
+#include "../lib.h"
+
+int get_shnodep_value (void);
+
+SYMBOL_EXPORT
+int get_shshdep_value (void) {
+  return get_shnodep_value ();
+}

test cases/common/153 recursive linking/shshdep/meson.build

@@ -0,0 +1 @@
+shshdep = shared_library('shshdep', 'lib.c', link_with : shnodep)

test cases/common/153 recursive linking/shstdep/lib.c

@@ -0,0 +1,8 @@
+#include "../lib.h"
+
+int get_stnodep_value (void);
+
+SYMBOL_EXPORT
+int get_shstdep_value (void) {
+  return get_stnodep_value ();
+}

test cases/common/153 recursive linking/shstdep/meson.build

@@ -0,0 +1 @@
+shstdep = shared_library('shstdep', 'lib.c', link_with : stnodep)

test cases/common/153 recursive linking/stnodep/lib.c

@@ -0,0 +1,6 @@
+#include "../lib.h"
+
+SYMBOL_EXPORT
+int get_stnodep_value (void) {
+  return 2;
+}

test cases/common/153 recursive linking/stnodep/meson.build

@@ -0,0 +1 @@
+stnodep = static_library('stnodep', 'lib.c')

test cases/common/153 recursive linking/stshdep/lib.c

@@ -0,0 +1,8 @@
+#include "../lib.h"
+
+int get_shnodep_value (void);
+
+SYMBOL_EXPORT
+int get_stshdep_value (void) {
+  return get_shnodep_value ();
+}

test cases/common/153 recursive linking/stshdep/meson.build

@@ -0,0 +1 @@
+stshdep = static_library('stshdep', 'lib.c', link_with : shnodep)

test cases/common/153 recursive linking/ststdep/lib.c

@@ -0,0 +1,8 @@
+#include "../lib.h"
+
+int get_stnodep_value (void);
+
+SYMBOL_EXPORT
+int get_ststdep_value (void) {
+  return get_stnodep_value ();
+}

test cases/common/153 recursive linking/ststdep/meson.build

@@ -0,0 +1 @@
+ststdep = static_library('ststdep', 'lib.c', link_with : stnodep)

test cases/frameworks/7 gnome/gir/meson.build

@@ -12,7 +12,7 @@ girlib = shared_library(
 girexe = executable(
   'girprog',
   sources : 'prog.c',
-  dependencies : [glib, gobj, gir],
+  dependencies : [glib, gobj, gir, dep1_dep],
   link_with : girlib
 )
 

test cases/vala/11 generated vapi/meson.build

@@ -6,7 +6,7 @@ subdir('libbar')
 
 vapiexe = executable('vapigen-test',
   'main.vala',
-  dependencies: [dependency('gobject-2.0'), libbar_vapi],
+  dependencies: [dependency('gobject-2.0'), libfoo_vapi, libbar_vapi],
   install: true,
 )