archer-sergiodj-stap -O2 -Wall warnings=errors

[Jan Kratochvil]

Hi Sergio,

with -O2 (+some -Wall or so options possibly - what applies for Fedora builds)
one gets:

gcc-4.6.0-0.14.fc15.x86_64
stap-probe.c: In function $B!F(Bstap_fetch_reg_value$B!G(B:
stap-probe.c:923:12: error: $B!F(Baop$B!G(B may be used uninitialized in this function [-Werror=uninitialized]
stap-probe.c:919:10: error: $B!F(Bret$B!G(B may be used uninitialized in this function [-Werror=uninitialized]
stap-probe.c: In function $B!F(Bstap_evaluate_conditionally$B!G(B:
stap-probe.c:1184:3: error: $B!F(Bres$B!G(B may be used uninitialized in this function [-Werror=uninitialized]

The attached patch needs a review, I have only briefly checked it is not
completely bogus.


Thanks,
Jan


--- a/gdb/stap-probe.c
+++ b/gdb/stap-probe.c
@@ -780,7 +780,9 @@ stap_fetch_reg_value (struct stap_evaluation_info *eval_info,
#define REG_NAME_MAX_SIZE 20
char regname[REG_NAME_MAX_SIZE + 1];
int len, regnum, indirect_p = 0;
- struct value *ret;
+ /* GCC false warning: $B!F(Bret$B!G(B may be used uninitialized in this function
+ */
+ struct value *ret = NULL;

/* The function which called us did not check if the expression
buffer was empty. */
@@ -851,7 +853,9 @@ stap_fetch_reg_value (struct stap_evaluation_info *eval_info,
if (indirect_p)
{
struct type *t = NULL;
- enum agent_op aop;
+ /* GCC false warning: $B!F(Baop$B!G(B may be used uninitialized in this function.
+ */
+ enum agent_op aop = 0;

/* If the user has specified that the register must be indirected,
we should know what's the correct type to cast it before making
@@ -949,7 +953,9 @@ stap_evaluate_single_operand (struct stap_evaluation_info *eval_info)
struct gdbarch *gdbarch = eval_info->gdbarch;
struct frame_info *frame = eval_info->frame;
enum stap_arg_bitness bitness = eval_info->bitness;
- struct value *res;
+ /* GCC false warning: $B!F(Bres$B!G(B may be used uninitialized in this function
+ */
+ struct value *res = NULL;

switch (*eval_info->exp_buf)
{

[Sergio Durigan Junior]

Hi Jan,

Post by Jan Kratochvil
Hi Sergio,
with -O2 (+some -Wall or so options possibly - what applies for Fedora builds)
gcc-4.6.0-0.14.fc15.x86_64
stap-probe.c:923:12: error: ‘aop’ may be used uninitialized in this function [-Werror=uninitialized]
stap-probe.c:919:10: error: ‘ret’ may be used uninitialized in this function [-Werror=uninitialized]
stap-probe.c:1184:3: error: ‘res’ may be used uninitialized in this
function [-Werror=uninitialized]

Thanks for pointing out those errors. They were fixed today (Sunday)
afternoon, after you tried to compile my branch. I compiled it here
with -O2 -Wall and everything worked.

Thanks.