target/armv7m: fix static analyzer warning

Despite of assert(is_packed) clang static analyser complains on use
of the uninitialized offset variable.

Cross compiling with latest x86_64-w64-mingw32-gcc hits warnings
	src/target/armv7m.c: In function ‘armv7m_read_core_reg’:
	src/target/armv7m.c:337:54: error: ‘reg32_id’ may be used
	    uninitialized in this function [-Werror=maybe-uninitialized]

It happens because mingw32 defines assert() without the attribute
"noreturn", whatever NDEBUG is defined or not.

Replace assert(is_packed) by if (is_packed) conditional and call
assert(false) in the else branch.

Change-Id: Id3c7dcccb65106e28be200b9a4d2b642f4d31019
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/6256
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-by: Andrzej Sierżęga <asier70@gmail.com>

diff --git a/src/target/armv7m.c b/src/target/armv7m.c
index 2bcb8abae0e050eb5bf973556b2633f2a62c1a7e..11770b5b5a12e7cd81e73e87503e8bb95f119e59 100644 (file)
--- a/src/target/armv7m.c
+++ b/src/target/armv7m.c
@@ -329,11 +329,17 @@ static int armv7m_read_core_reg(struct target *target, struct reg *r,
 
        if (r->size <= 8) {
                /* any 8-bit or shorter register is packed */
-               uint32_t offset = 0;    /* silence false gcc warning */
+               uint32_t offset;
                unsigned int reg32_id;
 
                bool is_packed = armv7m_map_reg_packing(num, &reg32_id, &offset);
-               assert(is_packed);
+               if (!is_packed) {
+                       /* We should not get here as all 8-bit or shorter registers
+                        * are packed */
+                       assert(false);
+                       /* assert() does nothing if NDEBUG is defined */
+                       return ERROR_FAIL;
+               }
                struct reg *r32 = &armv7m->arm.core_cache->reg_list[reg32_id];
 
                /* Read 32-bit container register if not cached */
@@ -394,11 +400,17 @@ static int armv7m_write_core_reg(struct target *target, struct reg *r,
 
        if (r->size <= 8) {
                /* any 8-bit or shorter register is packed */
-               uint32_t offset = 0;    /* silence false gcc warning */
+               uint32_t offset;
                unsigned int reg32_id;
 
                bool is_packed = armv7m_map_reg_packing(num, &reg32_id, &offset);
-               assert(is_packed);
+               if (!is_packed) {
+                       /* We should not get here as all 8-bit or shorter registers
+                        * are packed */
+                       assert(false);
+                       /* assert() does nothing if NDEBUG is defined */
+                       return ERROR_FAIL;
+               }
                struct reg *r32 = &armv7m->arm.core_cache->reg_list[reg32_id];
 
                if (!r32->valid) {