https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79918
Bug ID: 79918
Summary: Feature request: Warning about (may potential)
misaligned address-reference
Product: gcc
Version: 5.4.0
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: meisenmann....@fh-salzburg.ac.at
Target Milestone: ---
Target: arm-none-eabi
Hi!
I'm currently working on porting code (from x86) to ARM-targets and detecting
(potential) "alignment-problems". By using the option '-Wcast-align', I'm able
determine some "problematic" implementations, but I haven't found an
warning-option to detect another issue: I.e., getting a (misaligned)
address-reference, if referencing a misaligned struct-member.
--- Begin: Test-Code ---
extern void foo(double* p);
struct __attribute__((packed)) una_t
{
char data[2];
double value;
};
void Test1(char* p)
{
foo((double*)p);
}
void Test2(struct una_t* p)
{
foo(&p->value);
}
--- End of Code ---
I think (IMHO), it should be possible to detect &p->value in Test2() as risk;
similar as the pointer-cast in Test1(), but based on referencing an unaligned
member of a struct-typ.
Perhaps, a corresponding warning-option could be introduced in a future release
...
Best regards from Salzburg,
Markus
