[PATCH V2] dtc: Implement -d option to write out a dependency file

[Stephen Warren]

This will allow callers to rebuild .dtb files when any of the /include/d
.dtsi files are modified, not just the top-level .dts file.

Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
v2: Replaced fputs/fputc with fprintf

This is an updated patch for dtc itself. Once it's accepted, I'll repost
the equivalent kernel patch.

 Documentation/manual.txt |    3 +++
 dtc.c                    |   20 +++++++++++++++++++-
 srcpos.c                 |    4 ++++
 srcpos.h                 |    1 +
 tests/dependencies.cmp   |    1 +
 tests/dependencies.dts   |    6 ++++++
 tests/deps_inc1.dtsi     |    1 +
 tests/deps_inc2.dtsi     |    1 +
 tests/run_tests.sh       |    4 ++++
 9 files changed, 40 insertions(+), 1 deletions(-)
 create mode 100644 tests/dependencies.cmp
 create mode 100644 tests/dependencies.dts
 create mode 100644 tests/deps_inc1.dtsi
 create mode 100644 tests/deps_inc2.dtsi

diff --git a/Documentation/manual.txt b/Documentation/manual.txt
index 14508f3..989c589 100644
--- a/Documentation/manual.txt
+++ b/Documentation/manual.txt
@@ -106,6 +106,9 @@ Options:
     -O <output_format>
 	The generated output format, as listed above.
 
+    -d <dependency_filename>
+	Generate a dependency file during compilation.
+
     -q
 	Quiet: -q suppress warnings, -qq errors, -qqq all
 
diff --git a/dtc.c b/dtc.c
index 15d2fc2..7a0c605 100644
--- a/dtc.c
+++ b/dtc.c
@@ -71,6 +71,7 @@ static void  __attribute__ ((noreturn)) usage(void)
 	fprintf(stderr, "\t\t\tasm - assembler source\n");
 	fprintf(stderr, "\t-V <output version>\n");
 	fprintf(stderr, "\t\tBlob version to produce, defaults to %d (relevant for dtb\n\t\tand asm output only)\n", DEFAULT_FDT_VERSION);
+	fprintf(stderr, "\t-d <output dependency file>\n");
 	fprintf(stderr, "\t-R <number>\n");
 	fprintf(stderr, "\t\tMake space for <number> reserve map entries (relevant for \n\t\tdtb and asm output only)\n");
 	fprintf(stderr, "\t-S <bytes>\n");
@@ -99,6 +100,7 @@ int main(int argc, char *argv[])
 	const char *inform = "dts";
 	const char *outform = "dts";
 	const char *outname = "-";
+	const char *depname = NULL;
 	int force = 0, sort = 0;
 	const char *arg;
 	int opt;
@@ -111,7 +113,7 @@ int main(int argc, char *argv[])
 	minsize    = 0;
 	padsize    = 0;
 
-	while ((opt = getopt(argc, argv, "hI:O:o:V:R:S:p:fqb:vH:s")) != EOF) {
+	while ((opt = getopt(argc, argv, "hI:O:o:V:d:R:S:p:fqb:vH:s")) != EOF) {
 		switch (opt) {
 		case 'I':
 			inform = optarg;
@@ -125,6 +127,9 @@ int main(int argc, char *argv[])
 		case 'V':
 			outversion = strtol(optarg, NULL, 0);
 			break;
+		case 'd':
+			depname = optarg;
+			break;
 		case 'R':
 			reservenum = strtol(optarg, NULL, 0);
 			break;
@@ -185,6 +190,14 @@ int main(int argc, char *argv[])
 	fprintf(stderr, "DTC: %s->%s  on file \"%s\"\n",
 		inform, outform, arg);
 
+	if (depname) {
+		depfile = fopen(depname, "w");
+		if (!depfile)
+			die("Couldn't open dependency file %s: %s\n", depname,
+			    strerror(errno));
+		fprintf(depfile, "%s:", outname);
+	}
+
 	if (streq(inform, "dts"))
 		bi = dt_from_source(arg);
 	else if (streq(inform, "fs"))
@@ -194,6 +207,11 @@ int main(int argc, char *argv[])
 	else
 		die("Unknown input format \"%s\"\n", inform);
 
+	if (depfile) {
+		fputc('\n', depfile);
+		fclose(depfile);
+	}
+
 	if (cmdline_boot_cpuid != -1)
 		bi->boot_cpuid_phys = cmdline_boot_cpuid;
 
diff --git a/srcpos.c b/srcpos.c
index 2dbc874..36a38e9 100644
--- a/srcpos.c
+++ b/srcpos.c
@@ -40,6 +40,7 @@ static char *dirname(const char *path)
 	return NULL;
 }
 
+FILE *depfile; /* = NULL */
 struct srcfile_state *current_srcfile; /* = NULL */
 
 /* Detect infinite include recursion. */
@@ -67,6 +68,9 @@ FILE *srcfile_relative_open(const char *fname, char **fullnamep)
 			    strerror(errno));
 	}
 
+	if (depfile)
+		fprintf(depfile, " %s", fullname);
+
 	if (fullnamep)
 		*fullnamep = fullname;
 	else
diff --git a/srcpos.h b/srcpos.h
index bd7966e..ce980ca 100644
--- a/srcpos.h
+++ b/srcpos.h
@@ -30,6 +30,7 @@ struct srcfile_state {
 	struct srcfile_state *prev;
 };
 
+extern FILE *depfile; /* = NULL */
 extern struct srcfile_state *current_srcfile; /* = NULL */
 
 FILE *srcfile_relative_open(const char *fname, char **fullnamep);
diff --git a/tests/dependencies.cmp b/tests/dependencies.cmp
new file mode 100644
index 0000000..bcd9432
--- /dev/null
+++ b/tests/dependencies.cmp
@@ -0,0 +1 @@
+dependencies.test.dtb: dependencies.dts deps_inc1.dtsi deps_inc2.dtsi
diff --git a/tests/dependencies.dts b/tests/dependencies.dts
new file mode 100644
index 0000000..2cfe31b
--- /dev/null
+++ b/tests/dependencies.dts
@@ -0,0 +1,6 @@
+/dts-v1/;
+
+/include/ "deps_inc1.dtsi"
+
+/ {
+};
diff --git a/tests/deps_inc1.dtsi b/tests/deps_inc1.dtsi
new file mode 100644
index 0000000..5c607dc
--- /dev/null
+++ b/tests/deps_inc1.dtsi
@@ -0,0 +1 @@
+/include/ "deps_inc2.dtsi"
diff --git a/tests/deps_inc2.dtsi b/tests/deps_inc2.dtsi
new file mode 100644
index 0000000..710cecc
--- /dev/null
+++ b/tests/deps_inc2.dtsi
@@ -0,0 +1 @@
+/* Empty */
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index da6f970..b96f6d8 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -353,6 +353,10 @@ dtc_tests () {
     run_sh_test dtc-fatal.sh -I dts -O dtb nosuchfile.dts
     run_sh_test dtc-fatal.sh -I dtb -O dtb nosuchfile.dtb
     run_sh_test dtc-fatal.sh -I fs -O dtb nosuchfile
+
+    # Dependencies
+    run_dtc_test -I dts -O dtb -o dependencies.test.dtb -d dependencies.test.d dependencies.dts
+    run_wrap_test cmp dependencies.test.d dependencies.cmp
 }
 
 cmp_tests () {
-- 
1.7.0.4