RuntimeIC::RuntimeIC(void* func_addr, int total_size) {
static StatCounter sc("num_runtime_ics");
sc.log();
if (ENABLE_RUNTIME_ICS) {
assert(SCRATCH_BYTES >= 0);
assert(SCRATCH_BYTES < 0x80); // This would break both the instruction encoding and the dwarf encoding
assert(SCRATCH_BYTES % 8 == 0);
#if RUNTIMEICS_OMIT_FRAME_PTR
/*
* prologue:
* sub $0x28, %rsp # 48 83 ec 28
*
* epilogue:
* add $0x28, %rsp # 48 83 c4 28
* retq # c3
*
*/
static const int PROLOGUE_SIZE = 4;
static const int EPILOGUE_SIZE = 5;
assert(SCRATCH_BYTES % 16 == 8);
#else
/*
* The prologue looks like:
* push %rbp # 55
* mov %rsp, %rbp # 48 89 e5
* sub $0x30, %rsp # 48 83 ec 30
*
* The epilogue is:
* add $0x30, %rsp # 48 83 c4 30
* pop %rbp # 5d
* retq # c3
*/
static const int PROLOGUE_SIZE = 8;
static const int EPILOGUE_SIZE = 6;
assert(SCRATCH_BYTES % 16 == 0);
#endif
static const int CALL_SIZE = 13;
int total_code_size = total_size - EH_FRAME_SIZE;
int patchable_size = total_code_size - (PROLOGUE_SIZE + CALL_SIZE + EPILOGUE_SIZE);
int total_size = total_code_size + EH_FRAME_SIZE;
assert(total_size == 512 && "we currently only have a 512 byte block memory manager");
addr = memory_manager_512b.alloc();
// the memory block contains the EH frame directly followed by the generated machine code.
void* eh_frame_addr = addr;
addr = (char*)addr + EH_FRAME_SIZE;
// printf("Allocated runtime IC at %p\n", addr);
std::unique_ptr<ICSetupInfo> setup_info(ICSetupInfo::initialize(true, patchable_size, ICSetupInfo::Generic));
uint8_t* pp_start = (uint8_t*)addr + PROLOGUE_SIZE;
uint8_t* pp_end = pp_start + patchable_size + CALL_SIZE;
SpillMap _spill_map;
PatchpointInitializationInfo initialization_info = initializePatchpoint3(
func_addr, pp_start, pp_end, 0 /* scratch_offset */, 0 /* scratch_size */, LiveOutSet(), _spill_map);
assert(_spill_map.size() == 0);
assert(initialization_info.slowpath_start == pp_start + patchable_size);
assert(initialization_info.slowpath_rtn_addr == pp_end);
assert(initialization_info.continue_addr == pp_end);
StackInfo stack_info(SCRATCH_BYTES, 0);
icinfo = registerCompiledPatchpoint(pp_start, pp_start + patchable_size, pp_end, pp_end, setup_info.get(),
stack_info, LiveOutSet());
assembler::Assembler prologue_assem((uint8_t*)addr, PROLOGUE_SIZE);
#if RUNTIMEICS_OMIT_FRAME_PTR
// If SCRATCH_BYTES is 8 or less, we could use more compact instruction encodings
// (push instead of sub), but it doesn't seem worth it for now.
prologue_assem.sub(assembler::Immediate(SCRATCH_BYTES), assembler::RSP);
#else
prologue_assem.push(assembler::RBP);
prologue_assem.mov(assembler::RSP, assembler::RBP);
prologue_assem.sub(assembler::Immediate(SCRATCH_BYTES), assembler::RSP);
#endif
assert(!prologue_assem.hasFailed());
assert(prologue_assem.isExactlyFull());
assembler::Assembler epilogue_assem(pp_end, EPILOGUE_SIZE);
#if RUNTIMEICS_OMIT_FRAME_PTR
epilogue_assem.add(assembler::Immediate(SCRATCH_BYTES), assembler::RSP);
#else
epilogue_assem.add(assembler::Immediate(SCRATCH_BYTES), assembler::RSP);
epilogue_assem.pop(assembler::RBP);
#endif
epilogue_assem.retq();
assert(!epilogue_assem.hasFailed());
assert(epilogue_assem.isExactlyFull());
if (RUNTIMEICS_OMIT_FRAME_PTR)
memcpy(eh_frame_addr, _eh_frame_template_ofp, _eh_frame_template_ofp_size);
else
memcpy(eh_frame_addr, _eh_frame_template_fp, _eh_frame_template_fp_size);
register_eh_frame.updateAndRegisterFrameFromTemplate((uint64_t)addr, total_code_size, (uint64_t)eh_frame_addr,
EH_FRAME_SIZE);
} else {
addr = func_addr;
}
}
int JitFragmentWriter::finishCompilation() {
RELEASE_ASSERT(!assembler->hasFailed(), "");
commit();
if (failed) {
blocks_aborted.insert(block);
code_block.fragmentAbort(false);
return 0;
}
if (assembler->hasFailed()) {
int bytes_written = assembler->bytesWritten();
// don't retry JITing very large blocks
const auto large_block_threshold = JitCodeBlock::code_size - 4096;
if (bytes_written > large_block_threshold) {
static StatCounter num_jit_large_blocks("num_baselinejit_skipped_large_blocks");
num_jit_large_blocks.log();
blocks_aborted.insert(block);
code_block.fragmentAbort(false);
} else {
// we ran out of space - we allow a retry and set shouldCreateNewBlock to true in order to allocate a new
// block for the next attempt.
code_block.fragmentAbort(true /* not_enough_space */);
}
return 0;
}
block->code = (void*)((uint64_t)entry_code + code_offset);
block->entry_code = (decltype(block->entry_code))entry_code;
// if any side exits point to this block patch them to a direct jump to this block
auto it = block_patch_locations.find(block);
if (it != block_patch_locations.end()) {
for (void* patch_location : it->second) {
assembler::Assembler patch_asm((uint8_t*)patch_location, min_patch_size);
int64_t offset = (uint64_t)block->code - (uint64_t)patch_location;
if (isLargeConstant(offset)) {
patch_asm.mov(assembler::Immediate(block->code), assembler::R11);
patch_asm.jmpq(assembler::R11);
} else
patch_asm.jmp(assembler::JumpDestination::fromStart(offset));
RELEASE_ASSERT(!patch_asm.hasFailed(), "you may have to increase 'min_patch_size'");
}
block_patch_locations.erase(it);
}
// if we have a side exit, remember its location for patching
if (side_exit_patch_location.first) {
void* patch_location = (uint8_t*)block->code + side_exit_patch_location.second;
block_patch_locations[side_exit_patch_location.first].push_back(patch_location);
}
for (auto&& pp_info : pp_infos) {
SpillMap _spill_map;
uint8_t* start_addr = pp_info.start_addr;
uint8_t* end_addr = pp_info.end_addr;
PatchpointInitializationInfo initialization_info
= initializePatchpoint3(pp_info.func_addr, start_addr, end_addr, 0 /* scratch_offset */,
0 /* scratch_size */, LiveOutSet(), _spill_map);
uint8_t* slowpath_start = initialization_info.slowpath_start;
uint8_t* slowpath_rtn_addr = initialization_info.slowpath_rtn_addr;
std::unique_ptr<ICInfo> pp
= registerCompiledPatchpoint(start_addr, slowpath_start, initialization_info.continue_addr,
slowpath_rtn_addr, pp_info.ic.get(), pp_info.stack_info, LiveOutSet());
pp->associateNodeWithICInfo(pp_info.node);
pp.release();
}
void* next_fragment_start = (uint8_t*)block->code + assembler->bytesWritten();
code_block.fragmentFinished(assembler->bytesWritten(), num_bytes_overlapping, next_fragment_start);
#if MOVING_GC
// If JitFragmentWriter is destroyed, we don't necessarily want the ICInfo to be destroyed also,
// because it may contain a list of references to pointers in generated code that still exists
// and we need to keep those around.
// TODO: When should these ICInfo be freed?
registerGCTrackedICInfo(ic_info.release());
#endif
return num_bytes_exit;
}
