helper/binarybuffer: fix clang static analyzer warnings

Writing bits to an uninitialized buffer generated false warnings.
Zero buffers before setting them by buf_set_u32|64()
(do it only if bit-by-bit copy loop is used,
zeroed buffer is not necessary if a fast path write is used)

Change-Id: I2f7f8ddb45b0cbd08d3e249534fc51f4b5cc6694
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/5383
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

src/target/riscv/riscv-011.c

@@ -280,7 +280,7 @@ static uint32_t dtmcontrol_scan(struct target *target, uint32_t out)
 {
 	struct scan_field field;
 	uint8_t in_value[4];
-	uint8_t out_value[4];
+	uint8_t out_value[4] = { 0 };
 
 	buf_set_u32(out_value, 0, 32, out);
 
@@ -422,7 +422,7 @@ static dbus_status_t dbus_scan(struct target *target, uint16_t *address_in,
 {
 	riscv011_info_t *info = get_info(target);
 	uint8_t in[8] = {0};
-	uint8_t out[8];
+	uint8_t out[8] = {0};
 	struct scan_field field = {
 		.num_bits = info->addrbits + DBUS_OP_SIZE + DBUS_DATA_SIZE,
 		.out_value = out,

src/target/riscv/riscv-013.c

@@ -402,7 +402,7 @@ static uint32_t dtmcontrol_scan(struct target *target, uint32_t out)
 {
 	struct scan_field field;
 	uint8_t in_value[4];
-	uint8_t out_value[4];
+	uint8_t out_value[4] = { 0 };
 
 	buf_set_u32(out_value, 0, 32, out);
 
@@ -468,6 +468,7 @@ static dmi_status_t dmi_scan(struct target *target, uint32_t *address_in,
 	}
 
 	memset(in, 0, num_bytes);
+	memset(out, 0, num_bytes);
 
 	assert(info->abits != 0);
 

src/target/riscv/riscv.c

@@ -203,7 +203,7 @@ static uint32_t dtmcontrol_scan(struct target *target, uint32_t out)
 {
 	struct scan_field field;
 	uint8_t in_value[4];
-	uint8_t out_value[4];
+	uint8_t out_value[4] = { 0 };
 
 	buf_set_u32(out_value, 0, 32, out);
 
@@ -540,7 +540,7 @@ int riscv_add_breakpoint(struct target *target, struct breakpoint *breakpoint)
 			return ERROR_FAIL;
 		}
 
-		uint8_t buff[4];
+		uint8_t buff[4] = { 0 };
 		buf_set_u32(buff, 0, breakpoint->length * CHAR_BIT, breakpoint->length == 4 ? ebreak() : ebreak_c());
 		int const retval = target_write_memory(target, breakpoint->address, 2, breakpoint->length / 2, buff);
 
@@ -1047,7 +1047,7 @@ static int riscv_run_algorithm(struct target *target, int num_mem_params,
 
 	/* Disable Interrupts before attempting to run the algorithm. */
 	uint64_t current_mstatus;
-	uint8_t mstatus_bytes[8];
+	uint8_t mstatus_bytes[8] = { 0 };
 
 	LOG_DEBUG("Disabling Interrupts");
 	struct reg *reg_mstatus = register_get_by_name(target->reg_cache,
@@ -1103,7 +1103,7 @@ static int riscv_run_algorithm(struct target *target, int num_mem_params,
 	reg_mstatus->type->set(reg_mstatus, mstatus_bytes);
 
 	/* Restore registers */
-	uint8_t buf[8];
+	uint8_t buf[8] = { 0 };
 	buf_set_u64(buf, 0, info->xlen[0], saved_pc);
 	if (reg_pc->type->set(reg_pc, buf) != ERROR_OK)
 		return ERROR_FAIL;