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// Mark stack as non-executable
#if defined(__linux__) && defined(__ELF__)
.section .note.GNU-stack, "", %progbits
#endif
.text
.code 32
.arm
.align
.global upcall_new_stack
.global upcall_del_stack
.global __morestack
.hidden __morestack
// r4 and r5 are scratch registers for __morestack due to llvm
// ARMFrameLowering::adjustForSegmentedStacks() implementation.
.type __morestack,%function
__morestack:
.fnstart
// Save frame pointer and return address
.save {r4, r5}
.save {lr}
.save {r6, fp, lr}
push {r6, fp, lr}
.movsp r6
mov r6, sp
.setfp fp, sp, #4
add fp, sp, #4
// Save argument registers of the original function
push {r0, r1, r2, r3, lr}
mov r0, r4 // The amount of stack needed
add r1, fp, #20 // Address of stack arguments
mov r2, r5 // Size of stack arguments
// Create new stack
bl upcall_new_stack@plt
// Hold new stack pointer
mov r5, r0
// Pop the saved arguments
pop {r0, r1, r2, r3, lr}
// Grab the return pointer
add r4, lr, #16 // Skip past the return
mov sp, r5 // Swich to the new stack
mov lr, pc
mov pc, r4 // Call the original function
// Switch back to rust stack
mov sp, r6
// Save return value
mov r4, r0
mov r5, r1
// Remove the new allocated stack
bl upcall_del_stack@plt
// Restore return value
mov r0, r4
mov r1, r5
// Return
pop {r6, fp, lr}
mov pc, lr
.fnend
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