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// Mark stack as non-executable
#if defined(__linux__) && defined(__ELF__)
.section .note.GNU-stack, "", @progbits
#endif
/*
__morestack
See i386/morestack.S for the lengthy, general explanation.
*/
.text
#if defined(__APPLE__) || defined(_WIN32)
#define UPCALL_NEW_STACK _upcall_new_stack
#define UPCALL_DEL_STACK _upcall_del_stack
#define MORESTACK ___morestack
#else
#define UPCALL_NEW_STACK upcall_new_stack
#define UPCALL_DEL_STACK upcall_del_stack
#define MORESTACK __morestack
#endif
.globl UPCALL_NEW_STACK
.globl UPCALL_DEL_STACK
.globl MORESTACK
#if defined(__linux__) || defined(__FreeBSD__)
.hidden MORESTACK
#else
#if defined(__APPLE__)
.private_extern MORESTACK
#endif
#endif
#ifdef __ELF__
.type MORESTACK,@function
#endif
#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
MORESTACK:
.cfi_startproc
pushq %rbp
// The CFA is 24 bytes above the register that it will
// be associated with for this frame (%rbp). That is 8
// bytes greater than a normal frame, to allow the unwinder
// to skip the partial frame of the original function.
.cfi_def_cfa_offset 24
// %rbp is -24 bytes from the CFA
.cfi_offset %rbp, -24
movq %rsp, %rbp
// Calculate the CFA as on offset from %ebp
.cfi_def_cfa_register %rbp
subq $56, %rsp
// Save argument registers of the original function
movq %rdi, (%rsp)
movq %rsi, 8(%rsp)
movq %rdx, 16(%rsp)
movq %rcx, 24(%rsp)
movq %r8, 32(%rsp)
movq %r9, 40(%rsp)
// Calculate the address of the stack arguments.
// We have the base pointer, __morestack's return address,
// and __morestack's caller's return address to skip
movq %rbp, %rax
addq $24, %rax // Base pointer, return address x2
// The arguments to __morestack are passed in %r10 & %r11
movq %r11, %rdx // Size of stack arguments
movq %rax, %rsi // Address of stack arguments
movq %r10, %rdi // The amount of stack needed
#ifdef __APPLE__
call UPCALL_NEW_STACK
#endif
#ifdef __linux__
call UPCALL_NEW_STACK@PLT
#endif
#ifdef __FreeBSD__
call UPCALL_NEW_STACK@PLT
#endif
// Pop the saved arguments
movq (%rsp), %rdi
movq 8(%rsp), %rsi
movq 16(%rsp), %rdx
movq 24(%rsp), %rcx
movq 32(%rsp), %r8
movq 40(%rsp), %r9
addq $56, %rsp
movq 8(%rbp),%r10 // Grab the return pointer.
incq %r10 // Skip past the `ret` in our parent frame
movq %rax,%rsp // Switch to the new stack.
call *%r10 // Reenter the caller function
// Switch back to the rust stack
movq %rbp, %rsp
// Save the return value
pushq %rax
#ifdef __APPLE__
call UPCALL_DEL_STACK
#endif
#ifdef __linux__
call UPCALL_DEL_STACK@PLT
#endif
#ifdef __FreeBSD__
call UPCALL_DEL_STACK@PLT
#endif
popq %rax // Restore the return value
popq %rbp
ret
.cfi_endproc
#else
MORESTACK:
ret
#endif
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