diff options
Diffstat (limited to 'rjit.c')
| -rw-r--r-- | rjit.c | 108 |
1 files changed, 106 insertions, 2 deletions
@@ -56,6 +56,12 @@ void rb_rjit(void) {} #endif #include "dln.h" +// For mmapp(), sysconf() +#ifndef _WIN32 +#include <unistd.h> +#include <sys/mman.h> +#endif + #include "ruby/util.h" // A copy of RJIT portion of MRI options since RJIT initialization. We @@ -261,6 +267,105 @@ rjit_compile(FILE *f, const rb_iseq_t *iseq, const char *funcname, int id) // New stuff from here // +#if defined(MAP_FIXED_NOREPLACE) && defined(_SC_PAGESIZE) +// Align the current write position to a multiple of bytes +static uint8_t * +align_ptr(uint8_t *ptr, uint32_t multiple) +{ + // Compute the pointer modulo the given alignment boundary + uint32_t rem = ((uint32_t)(uintptr_t)ptr) % multiple; + + // If the pointer is already aligned, stop + if (rem == 0) + return ptr; + + // Pad the pointer by the necessary amount to align it + uint32_t pad = multiple - rem; + + return ptr + pad; +} +#endif + +// Address space reservation. Memory pages are mapped on an as needed basis. +// See the Rust mm module for details. +static uint8_t * +rb_mjit_reserve_addr_space(uint32_t mem_size) +{ +#ifndef _WIN32 + uint8_t *mem_block; + + // On Linux + #if defined(MAP_FIXED_NOREPLACE) && defined(_SC_PAGESIZE) + uint32_t const page_size = (uint32_t)sysconf(_SC_PAGESIZE); + uint8_t *const cfunc_sample_addr = (void *)&rb_mjit_reserve_addr_space; + uint8_t *const probe_region_end = cfunc_sample_addr + INT32_MAX; + // Align the requested address to page size + uint8_t *req_addr = align_ptr(cfunc_sample_addr, page_size); + + // Probe for addresses close to this function using MAP_FIXED_NOREPLACE + // to improve odds of being in range for 32-bit relative call instructions. + do { + mem_block = mmap( + req_addr, + mem_size, + PROT_NONE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE, + -1, + 0 + ); + + // If we succeeded, stop + if (mem_block != MAP_FAILED) { + break; + } + + // +4MB + req_addr += 4 * 1024 * 1024; + } while (req_addr < probe_region_end); + + // On MacOS and other platforms + #else + // Try to map a chunk of memory as executable + mem_block = mmap( + (void *)rb_mjit_reserve_addr_space, + mem_size, + PROT_NONE, + MAP_PRIVATE | MAP_ANONYMOUS, + -1, + 0 + ); + #endif + + // Fallback + if (mem_block == MAP_FAILED) { + // Try again without the address hint (e.g., valgrind) + mem_block = mmap( + NULL, + mem_size, + PROT_NONE, + MAP_PRIVATE | MAP_ANONYMOUS, + -1, + 0 + ); + } + + // Check that the memory mapping was successful + if (mem_block == MAP_FAILED) { + perror("ruby: yjit: mmap:"); + if(errno == ENOMEM) { + // No crash report if it's only insufficient memory + exit(EXIT_FAILURE); + } + rb_bug("mmap failed"); + } + + return mem_block; +#else + // Windows not supported for now + return NULL; +#endif +} + // JIT buffer uint8_t *rb_rjit_mem_block = NULL; @@ -485,8 +590,7 @@ rjit_init(const struct rjit_options *opts) VM_ASSERT(rjit_enabled); rjit_opts = *opts; - extern uint8_t* rb_yjit_reserve_addr_space(uint32_t mem_size); - rb_rjit_mem_block = rb_yjit_reserve_addr_space(RJIT_CODE_SIZE); + rb_rjit_mem_block = rb_mjit_reserve_addr_space(RJIT_CODE_SIZE); // RJIT doesn't support miniruby, but it might reach here by RJIT_FORCE_ENABLE. rb_mRJIT = rb_const_get(rb_cRubyVM, rb_intern("RJIT")); |