Add support for dependency files in custom targets.

6 files changed, 54 insertions, 3 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 1f1c3ca..4d0af4b 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -551,6 +551,11 @@ class Backend():
             else:
                 if '@OUTDIR@' in i:
                     i = i.replace('@OUTDIR@', outdir)
+                elif '@DEPFILE@' in i:
+                    if target.depfile is None:
+                        raise MesonException('Custom target %s has @DEPFILE@ but no depfile keyword argument.' % target.name)
+                    dfilename = os.path.join(self.get_target_private_dir(target), target.depfile)
+                    i = i.replace('@DEPFILE@', dfilename)
                 elif '@PRIVATE_OUTDIR_' in i:
                     match = re.search('@PRIVATE_OUTDIR_(ABS_)?([-a-zA-Z0-9.@:]*)@', i)
                     source = match.group(0)
@@ -558,7 +563,6 @@ class Backend():
                         lead_dir = ''
                     else:
                         lead_dir = self.environment.get_build_dir()
-                    target_id = match.group(2)
                     i = i.replace(source,
                                   os.path.join(lead_dir,
                                                outdir))
diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 15f298b..eacfda4 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -366,7 +366,11 @@ int dummy;
         desc = 'Generating {0} with a {1} command.'
         if target.build_always:
             deps.append('PHONY')
-        elem = NinjaBuildElement(self.all_outputs, ofilenames, 'CUSTOM_COMMAND', srcs)
+        if target.depfile is None:
+            rulename = 'CUSTOM_COMMAND'
+        else:
+            rulename = 'CUSTOM_COMMAND_DEP'
+        elem = NinjaBuildElement(self.all_outputs, ofilenames, rulename, srcs)
         for i in target.depend_files:
             if isinstance(i, mesonlib.File):
                 deps.append(i.rel_to_builddir(self.build_to_src))
@@ -394,6 +398,11 @@ int dummy;
         else:
             cmd_type = 'custom'
 
+        if target.depfile is not None:
+            rel_dfile = os.path.join(self.get_target_private_dir(target), target.depfile)
+            abs_pdir = os.path.join(self.environment.get_build_dir(), self.get_target_private_dir(target))
+            os.makedirs(abs_pdir, exist_ok=True)
+            elem.add_item('DEPFILE', rel_dfile)
         elem.add_item('COMMAND', cmd)
         elem.add_item('description',  desc.format(target.name, cmd_type))
         elem.write(outfile)
@@ -636,7 +645,6 @@ int dummy;
             velem.write(outfile)
 
         # And then benchmarks.
-        benchmark_script = os.path.join(script_root, 'meson_benchmark.py')
         cmd = [sys.executable, self.environment.get_build_command(), '--internal', 'benchmark', benchmark_data]
         elem = NinjaBuildElement(self.all_outputs, 'benchmark', 'CUSTOM_COMMAND', ['all', 'PHONY'])
         elem.add_item('COMMAND', cmd)
@@ -657,6 +665,14 @@ int dummy;
         outfile.write(' command = $COMMAND\n')
         outfile.write(' description = $DESC\n')
         outfile.write(' restat = 1\n\n')
+        # Ninja errors out if you have deps = gcc but no depfile, so we must
+        # have two rules for custom commands.
+        outfile.write('rule CUSTOM_COMMAND_DEP\n')
+        outfile.write(' command = $COMMAND\n')
+        outfile.write(' description = $DESC\n')
+        outfile.write(' deps = gcc\n')
+        outfile.write(' depfile = $DEPFILE\n')
+        outfile.write(' restat = 1\n\n')
         outfile.write('rule REGENERATE_BUILD\n')
         c = (quote_char + ninja_quote(sys.executable) + quote_char,
              quote_char + ninja_quote(self.environment.get_build_command())  + quote_char,
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 0922dfb..c92c99f 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -931,6 +931,7 @@ class CustomTarget:
                     'build_always' : True,
                     'depends' : True,
                     'depend_files' : True,
+                    'depfile' : True,
                     }
 
     def __init__(self, name, subdir, kwargs):
@@ -939,6 +940,7 @@ class CustomTarget:
         self.dependencies = []
         self.extra_depends = []
         self.depend_files = [] # Files that this target depends on but are not on the command line.
+        self.depfile = None
         self.process_kwargs(kwargs)
         self.extra_files = []
         self.install_rpath = ''
@@ -983,6 +985,13 @@ class CustomTarget:
                 raise InvalidArguments('Output must not contain a path segment.')
         if 'command' not in kwargs:
             raise InvalidArguments('Missing keyword argument "command".')
+        if 'depfile' in kwargs:
+            depfile = kwargs['depfile']
+            if not isinstance(depfile, str):
+                raise InvalidArguments('Depfile must be a string.')
+            if os.path.split(depfile)[1] != depfile:
+                raise InvalidArguments('Depfile must be a plain filename without a subdirectory.')
+            self.depfile = depfile
         cmd = kwargs['command']
         if not(isinstance(cmd, list)):
             cmd = [cmd]
diff --git a/test cases/common/56 custom target/depfile/dep.py b/test cases/common/56 custom target/depfile/dep.py
new file mode 100755
index 0000000..3a772ec
--- /dev/null
+++ b/test cases/common/56 custom target/depfile/dep.py
@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+
+import sys, os
+from glob import glob
+
+_, srcdir, depfile, output = sys.argv
+
+depfiles = glob(os.path.join(srcdir, '*'))
+
+quoted_depfiles = [x.replace(' ', '\ ') for x in depfiles]
+
+open(output, 'w').write('I am the result of globbing.')
+open(depfile, 'w').write('%s: %s\n' % (output, ' '.join(quoted_depfiles)))
diff --git a/test cases/common/56 custom target/depfile/meson.build b/test cases/common/56 custom target/depfile/meson.build
new file mode 100644
index 0000000..46bca74
--- /dev/null
+++ b/test cases/common/56 custom target/depfile/meson.build
@@ -0,0 +1,7 @@
+
+
+mytarget = custom_target('depfile',
+  output : 'dep.dat',
+  depfile : 'dep.dat.d',
+  command : [find_program('dep.py'), meson.current_source_dir(), '@DEPFILE@', '@OUTPUT@'],
+)
diff --git a/test cases/common/56 custom target/meson.build b/test cases/common/56 custom target/meson.build
index db81824..e216bae 100644
--- a/test cases/common/56 custom target/meson.build
+++ b/test cases/common/56 custom target/meson.build
@@ -13,3 +13,5 @@ command : [python, comp, '@INPUT@', '@OUTPUT@'],
 install : true,
 install_dir : 'subdir'
 )
+
+subdir('depfile')