add libfirmprof helper library

support/libfirmprof/Makefile

+GOAL=libfirmprof.a
+LFLAGS=
+CFLAGS=-Wall -W
+OBJECTS=instrument.o
+CC?=gcc
+AR?=ar
+RANLIB?=ranlib
+
+.PHONY: clean
+
+all: $(GOAL)
+
+$(GOAL): $(OBJECTS)
+	$(AR) rc $@ $(OBJECTS)
+	$(RANLIB) $@
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+clean:
+	rm -rf $(GOAL) $(OBJECTS)

support/libfirmprof/instrument.c

+/**
+ * Helper code to output instrumentation results
+ *  @author Matthias Braun, Steven Schaefer
+ */
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+/* Prevent the compiler from mangling the name of this function. */
+void __init_firmprof(const char*, unsigned int*, size_t)
+     asm("__init_firmprof");
+
+typedef struct _profile_counter_t {
+	const char *filename;
+	unsigned   *counters;
+	unsigned    len;
+	struct _profile_counter_t *next;
+} profile_counter_t;
+
+static profile_counter_t *counters = NULL;
+
+static void write_profiles(void)
+{
+	profile_counter_t *counter = counters;
+	while(counter != NULL) {
+		profile_counter_t *next = counter->next;
+		FILE *f = fopen(counter->filename, "wb");
+		if (f == NULL) {
+			perror("Warning: couldn't open file for writing profiling data");
+		} else {
+			fputs("firmprof", f);
+			fwrite(counter->counters, counter->len * sizeof(unsigned), 1, f);
+			fclose(f);
+		}
+		free(counter);
+		counter = next;
+	}
+}
+
+/**
+ * Register a new profile counter. This is called by separate constructors
+ * for each translation unit. Incidentally, referring to this function as
+ * "__init_firmprof" is perfectly linker friendly.
+ */
+void __init_firmprof(const char *filename,
+                      unsigned int *counts, size_t len)
+{
+	static int initialized = 0;
+	profile_counter_t *counter;
+
+	if (!initialized) {
+		initialized = 1;
+		atexit(write_profiles);
+	}
+
+	counter = (profile_counter_t*) malloc(sizeof(*counter));
+	if (counter == NULL)
+		return;
+
+	counter->filename = filename;
+	counter->counters = counts;
+	counter->next     = counters;
+	counter->len      = len;
+
+	counters = counter;
+}