llvm-project/compiler-rt/test/shadowcallstack/libc_support.h

38 lines
950 B
C

// This header provides replacements for certain libc functions. It is necessary
// in order to safely run the tests on aarch64, because the system libc might
// not have been compiled with -ffixed-x18.
#pragma once
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#ifdef __aarch64__
size_t scs_strlen(const char *p) {
size_t retval = 0;
while (*p++)
retval++;
return retval;
}
// We mark this function as noinline to make sure that its callers do not
// become leaf functions as a result of inlining. This is because we want to
// make sure that we generate the correct code for non-leaf functions.
__attribute__((noinline)) void scs_fputs_stdout(const char *p) {
__asm__ __volatile__(
"mov x0, #1\n" // stdout
"mov x1, %0\n"
"mov x2, %1\n"
"mov x8, #64\n" // write
"svc #0\n" ::"r"(p),
"r"(scs_strlen(p))
: "x0", "x1", "x2", "x8");
}
#else
#error Unsupported platform
#endif