ccroot.py: add skip_stlib_deps feature

demos/c/stlib-deps/libA/external_vars.c

@@ -0,0 +1,11 @@
+
+#include <stdio.h>
+#include "external_vars.h"
+
+int k = 5;
+
+void print_value_of_k() {
+
+    printf("K = %d\n", k);
+
+}

demos/c/stlib-deps/libA/external_vars.h

@@ -0,0 +1,14 @@
+/*
+   Export internal vars
+   */
+
+#ifndef _EXTERNAL_VARS_H
+#define _EXTERNAL_VARS_H
+
+extern int k; /* export k */
+
+void print_value_of_k();
+
+extern int r;
+
+#endif /*_EXTERNAL_VARS_H */

demos/c/stlib-deps/libA/wscript_build

@@ -0,0 +1,7 @@
+# This is a static library that provides a header to include reference to
+# internal variables.
+bld.stlib(
+	target='A',
+	source='external_vars.c',
+	includes='.',
+	export_includes='.')

demos/c/stlib-deps/libB/sum.c

@@ -0,0 +1,12 @@
+
+#include <stdio.h>
+
+#include "sum.h"
+
+#include "external_vars.h"
+
+void sum(int j) {
+    printf("Adding %d...\n", j);
+    // Add our new value
+    k += j;
+}

demos/c/stlib-deps/libB/sum.h

@@ -0,0 +1,10 @@
+/*
+   Export internal vars
+   */
+
+#ifndef _SUM_H
+#define _SUM_H
+
+void sum(int j);
+
+#endif /*_SUM_H */

demos/c/stlib-deps/libB/wscript_build

@@ -0,0 +1,9 @@
+# This script uses libA to do some internal logic. It uses the default
+# behavior so it will be re-archived every time libA changes, even if
+# changes in libA are only visible at runtime.
+bld.stlib(
+	target='B',
+	source='sum.c',
+	use='A',
+	includes='.',
+	export_includes='.')

demos/c/stlib-deps/libC/diff.c

@@ -0,0 +1,13 @@
+
+#include <stdio.h>
+
+#include "diff.h"
+
+#include "external_vars.h"
+
+void diff(int j) {
+
+    printf("Subtracting %d...\n", j);
+    // subtract our new value
+    k -= j;
+}

demos/c/stlib-deps/libC/diff.h

@@ -0,0 +1,10 @@
+/*
+   Export internal vars
+   */
+
+#ifndef _DIFF_H
+#define _DIFF_H
+
+void diff(int j);
+
+#endif /* _DIFF_H */

demos/c/stlib-deps/libC/wscript_build

@@ -0,0 +1,10 @@
+# This script uses the logic that prevents static libraries from depending on
+# eachother. This means that the only way libC is re-archived is if the source
+# code file diff.c or any of its depenencies change.
+bld.stlib(
+	target='C',
+	source='diff.c',
+	features='skip_stlib_link_deps',
+	use='A',
+	includes='.',
+	export_includes='.')

demos/c/stlib-deps/main.c

@@ -0,0 +1,22 @@
+
+#include <stdio.h>
+
+#include "external_vars.h"
+#include "sum.h"
+#include "diff.h"
+
+int main()
+{
+    /* This should return to whatever the default value is. */
+    print_value_of_k();
+    sum(6);
+    print_value_of_k();
+    diff(8);
+    print_value_of_k();
+    sum(8);
+    print_value_of_k();
+    diff(6);
+    print_value_of_k();
+
+    return 0;
+}

demos/c/stlib-deps/wscript_build

@@ -0,0 +1,11 @@
+#! /usr/bin/env python
+
+bld.recurse('libA')
+bld.recurse('libB')
+bld.recurse('libC')
+
+# Note that main has an implied dependency between our main program and libA
+bld.program(
+	source   = 'main.c',
+	target   = 'test_static_link_chain',
+	use      = 'B C')

demos/c/wscript

@@ -75,7 +75,7 @@ def configure(conf):
 def build(bld):
 	bld.env.DEFINES=['WAF=1']
 
-	bld.recurse('program stlib shlib')
+	bld.recurse('program stlib stlib-deps shlib')
 	#bld.install_files('/tmp/foo', 'wscript')
 	#bld.env.PREFIX='/tmp/foo'
 	bld.install_files('${PREFIX}/', 'program/a.h  program/main.c', relative_trick=False)

waflib/Tools/ccroot.py

@@ -238,6 +238,17 @@ def rm_tgt(cls):
 	setattr(cls, 'run', wrap)
 rm_tgt(stlink_task)
 
+@feature('skip_stlib_link_deps')
+@before_method('process_use')
+def apply_skip_stlib_link_deps(self):
+	"""
+	This enables an optimization in the :py:func:wafilb.Tools.ccroot.processes_use: method that skips dependency and
+	link flag optimizations for targets that generate static libraries (via the :py:class:Tools.ccroot.stlink_task task).
+	The actual behavior is implemented in :py:func:wafilb.Tools.ccroot.processes_use: method so this feature only tells waf
+	to enable the new behavior.
+	"""
+	self.env.SKIP_STLIB_LINK_DEPS = True
+
 @feature('c', 'cxx', 'd', 'fc', 'asm')
 @after_method('process_source')
 def apply_link(self):
@@ -386,7 +397,11 @@ def process_use(self):
 		y = self.bld.get_tgen_by_name(x)
 		var = y.tmp_use_var
 		if var and link_task:
-			if var == 'LIB' or y.tmp_use_stlib or x in names:
+			if self.env.SKIP_STLIB_LINK_DEPS and isinstance(link_task, stlink_task):
+				# If the skip_stlib_link_deps feature is enabled then we should
+				# avoid adding lib deps to the stlink_task instance.
+				pass
+			elif var == 'LIB' or y.tmp_use_stlib or x in names:
 				self.env.append_value(var, [y.target[y.target.rfind(os.sep) + 1:]])
 				self.link_task.dep_nodes.extend(y.link_task.outputs)
 				tmp_path = y.link_task.outputs[0].parent.path_from(self.get_cwd())