Simplify assert() to reduce memory usage

The behaviour of assert() now depends on the value of the new optional
platform define `PLAT_LOG_LEVEL_ASSERT`. This defaults to `LOG_LEVEL` if
not defined by the platform.

- If `PLAT_LOG_LEVEL_ASSERT` >= `LOG_LEVEL_VERBOSE`, it prints the file
  name, line and asserted expression.
- If `PLAT_LOG_LEVEL_ASSERT` >= `LOG_LEVEL_INFO`, it prints the file
  name and line.
- If not, it doesn't print anything.

Note the old behaviour was to print the function name whereas now it
prints the file name. This reduces memory usage because the file name is
shared between all assert calls in a given file. Also, the default
behaviour in debug builds is to no longer print the asserted expression,
greatly reducing the string usage.

For FVP debug builds this change saves approximately:

              No TBBR    TBBR
        BL1    1.6 KB   2.2 KB
        BL2    1.7 KB   2.1 KB
        BL31   2.6 KB   3.3 KB

Change-Id: I2947569d593df0b25611dc3c7a6096f42155c115
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/include/lib/stdlib/assert.h b/include/lib/stdlib/assert.h
index 1bcd1ea..db567db 100644
--- a/include/lib/stdlib/assert.h
+++ b/include/lib/stdlib/assert.h
@@ -42,19 +42,36 @@
 #ifndef _ASSERT_H_
 #define _ASSERT_H_
 
+#include <debug.h>
+#include <platform_def.h>
 #include <sys/cdefs.h>
 
+#ifndef PLAT_LOG_LEVEL_ASSERT
+#define PLAT_LOG_LEVEL_ASSERT	LOG_LEVEL
+#endif
+
 #if ENABLE_ASSERTIONS
 #define	_assert(e)	assert(e)
-#define	assert(e)	((e) ? (void)0 : __assert(__func__, __FILE__, \
-			    __LINE__, #e))
+# if PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_VERBOSE
+#  define	assert(e)	((e) ? (void)0 : __assert(__FILE__, __LINE__, #e))
+# elif PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_INFO
+#  define	assert(e)	((e) ? (void)0 : __assert(__FILE__, __LINE__))
+# else
+#  define	assert(e)	((e) ? (void)0 : __assert())
+# endif
 #else
 #define	assert(e)	((void)0)
 #define	_assert(e)	((void)0)
 #endif /* ENABLE_ASSERTIONS */
 
 __BEGIN_DECLS
-void __assert(const char *, const char *, int, const char *) __dead2;
+#if PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_VERBOSE
+void __assert(const char *, unsigned int, const char *) __dead2;
+#elif PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_INFO
+void __assert(const char *, unsigned int) __dead2;
+#else
+void __assert(void) __dead2;
+#endif
 __END_DECLS
 
 #endif /* !_ASSERT_H_ */