Construct linked list of gcov data structures

The gcov constructors call __gcov_init() for each gcov covered file,
which we then need to turn into a linked list of all gcov files so
that we can traverse them later to pull out gcov profiling data.

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

3 files changed, 68 insertions, 4 deletions

diff --git a/Makefile.main b/Makefile.main
index bd03ff4..c01b16b 100644
--- a/Makefile.main
+++ b/Makefile.main
@@ -53,7 +53,7 @@ CPPFLAGS += -ffreestanding
 CFLAGS := -fno-strict-aliasing -fstack-protector-all -pie -mbig-endian -m64
 
 ifeq ($(SKIBOOT_GCOV),1)
-CFLAGS += -fprofile-arcs -ftest-coverage
+CFLAGS += -fprofile-arcs -ftest-coverage -DSKIBOOT_GCOV=1
 endif
 
 ifeq ($(STACK_CHECK),1)
diff --git a/core/gcov-profiling.c b/core/gcov-profiling.c
index 453ae7f..cf8b509 100644
--- a/core/gcov-profiling.c
+++ b/core/gcov-profiling.c
@@ -14,11 +14,43 @@
  * limitations under the License.
  */
 
+#include <skiboot.h>
 #include <compiler.h>
+#include <stdio.h>
 
 typedef long gcov_type;
 
-void __gcov_init(void* f) __attrconst;
+/*
+ * This is GCC internal data structure. See GCC libgcc/libgcov.h for
+ * details.
+ *
+ * If gcc changes this, we have to change it.
+ */
+
+typedef unsigned int gcov_unsigned_int;
+
+#if __GNUC__ == 4 && __GNUC_MINOR__ >= 9
+#define GCOV_COUNTERS                   9
+#else
+#define GCOV_COUNTERS                   8
+#endif
+
+struct gcov_info
+{
+        gcov_unsigned_int version;
+        struct gcov_info *next;
+        gcov_unsigned_int stamp;
+        const char *filename;
+        void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
+        unsigned int n_functions;
+        struct gcov_fn_info **functions;
+};
+
+/* We have a list of all gcov info set up at startup */
+struct gcov_info *gcov_info_list;
+
+void __gcov_init(struct gcov_info* f);
+void skiboot_gcov_done(void);
 void __gcov_flush(void) __attrconst;
 void __gcov_merge_add(gcov_type *counters, unsigned int n_counters) __attrconst;
 void __gcov_merge_single(gcov_type *counters, unsigned int n_counters) __attrconst;
@@ -26,13 +58,37 @@ void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters) __attrcons
 void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters) __attrconst;
 void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters) __attrconst;
 
-void __gcov_init(void* f)
+void __gcov_init(struct gcov_info* f)
 {
-	(void)f;
+	static gcov_unsigned_int version = 0;
 
+	if (version == 0) {
+		printf("GCOV version: %u\n", f->version);
+		version = f->version;
+	}
+
+	if (gcov_info_list)
+		f->next = gcov_info_list;
+
+	gcov_info_list = f;
 	return;
 }
 
+void skiboot_gcov_done(void)
+{
+	struct gcov_info *i = gcov_info_list;
+
+	if (i->filename)
+		printf("GCOV: gcov_info_list looks sane (first file: %s)\n",
+		       i->filename);
+	else
+		prlog(PR_WARNING, "GCOV: gcov_info_list doesn't look sane. "
+		      "i->filename == NULL.");
+
+	printf("GCOV: gcov_info_list at 0x%p\n", gcov_info_list);
+}
+
+
 void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
 {
 	(void)counters;
diff --git a/core/init.c b/core/init.c
index d4c0c25..0e28f95 100644
--- a/core/init.c
+++ b/core/init.c
@@ -56,6 +56,10 @@ enum proc_gen proc_gen;
 static uint64_t kernel_entry;
 static bool kernel_32bit;
 
+#ifdef SKIBOOT_GCOV
+void skiboot_gcov_done(void);
+#endif
+
 struct debug_descriptor debug_descriptor = {
 	.eye_catcher	= "OPALdbug",
 	.version	= DEBUG_DESC_VERSION,
@@ -585,6 +589,10 @@ void __noreturn main_cpu_entry(const void *fdt, u32 master_cpu)
 	       (debug_descriptor.console_log_levels & 0x0f));
 	prlog(PR_TRACE, "You will not see this\n");
 
+#ifdef SKIBOOT_GCOV
+	skiboot_gcov_done();
+#endif
+
 	/* Initialize boot cpu's cpu_thread struct */
 	init_boot_cpu();