When allocating stack space with a larger alignment than the known stack
alignment a temporary register is used for storing the stack pointer.
Ensure that this isn't one of the registers used for passing arguments.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
%if %1 != 0 && required_stack_alignment > STACK_ALIGNMENT
%if %1 > 0
%assign regs_used (regs_used + 1)
- %elif ARCH_X86_64 && regs_used == num_args && num_args <= 4 + UNIX64 * 2
- %warning "Stack pointer will overwrite register argument"
+ %endif
+ %if ARCH_X86_64 && regs_used < 5 + UNIX64 * 3
+ ; Ensure that we don't clobber any registers containing arguments. For UNIX64 we also preserve r6 (rax)
+ ; since it's used as a hidden argument in vararg functions to specify the number of vector registers used.
+ %assign regs_used 5 + UNIX64 * 3
%endif
%endif
%endif