Fix compiler check for stack unwind hint

The check inserts a DWARF directive to tell stack unwinding that the
bottom of the (co-routine) stack has been reached. Without this, stack
traces may attempt to continue past the bottom of the stack.

The GCC version check was incorrect, and failed to trigger for GCC
version 5.[0123].
This commit is contained in:
Kristian Nielsen 2016-06-08 15:12:44 +02:00
parent 4f1ad43992
commit 196d96cc8f

View file

@ -206,7 +206,7 @@ my_context_spawn(struct my_context *c, void (*f)(void *), void *d)
(
"movq %%rsp, (%[save])\n\t"
"movq %[stack], %%rsp\n\t"
#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 4 && !defined(__INTEL_COMPILER)
#if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)) && !defined(__INTEL_COMPILER)
/*
This emits a DWARF DW_CFA_undefined directive to make the return address
undefined. This indicates that this is the top of the stack frame, and
@ -456,7 +456,7 @@ my_context_spawn(struct my_context *c, void (*f)(void *), void *d)
(
"movl %%esp, (%[save])\n\t"
"movl %[stack], %%esp\n\t"
#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 4 && !defined(__INTEL_COMPILER)
#if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)) && !defined(__INTEL_COMPILER)
/*
This emits a DWARF DW_CFA_undefined directive to make the return address
undefined. This indicates that this is the top of the stack frame, and