[Bug target/87014] [x32] __builtin_eh_return should use 64-bit mov to set return address

[theonetruecamper at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87014

--- Comment #5 from camper  ---
test case (-O0):

using ll = long long;

void fillstack() {
ll foo[] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
};
}

void f(ll=-1,ll=-1,ll=-1,ll=-1,ll=-1,ll=-1,ll arg7_on_stack=-1) {
throw 0;
}

void g() {
try {
f();
} catch(int) {
}
}

int main() {
   fillstack();
   g();
}

[Bug target/87014] [x32] __builtin_eh_return should use 64-bit mov to set return address

[theonetruecamper at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87014

--- Comment #1 from camper  ---
Created attachment 44557
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44557&action=edit
[x32] use 64-bit mov to set return address in eh_return

compiles to:
movlhandler(%rip), %eax
movloffset(%rip), %edx
movl%edx, %ecx
movl%eax, %eax
movq%rax, 8(%ebp,%ecx)
movq-16(%ebp), %rax
movq-8(%ebp), %rdx
leal8(%rbp,%rcx), %ecx
movl0(%ebp), %ebp
movl%ecx, %esp
ret

[Bug target/87014] New: [x32] __builtin_eh_return should use 64-bit mov to set return address

[theonetruecamper at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87014

Bug ID: 87014
   Summary: [x32] __builtin_eh_return should use 64-bit mov to set
return address
   Product: gcc
   Version: unknown
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: target
  Assignee: unassigned at gcc dot gnu.org
  Reporter: theonetruecamper at gmx dot de
  Target Milestone: ---

long offset;
void* ptr;

void f(void)
{
__builtin_eh_return(offset,ptr);
}

with gcc -mx32 produces (gcc (Gentoo Hardened 7.3.0-r3 p1.4) 7.3.0)

f:
pushq   %rbp
movl%esp, %ebp
pushq   %rdx
pushq   %rax
movl%fs:24, %eax
movl%eax, -20(%ebp)
xorl%eax, %eax
movlptr(%rip), %eax
movloffset(%rip), %edx
movl%edx, %ecx
movl%eax, 8(%ebp,%ecx)# !
movq-16(%ebp), %rax
movq-8(%ebp), %rdx
leal8(%rbp,%rcx), %ecx
movl0(%ebp), %ebp
movl%ecx, %esp
ret   # !!

Since the upper half of the return address is not cleared this can lead to
SIGSEGV in _Unwind_*