diff options
Diffstat (limited to 'deps/v8/src/x64/deoptimizer-x64.cc')
| -rw-r--r-- | deps/v8/src/x64/deoptimizer-x64.cc | 41 |
1 files changed, 39 insertions, 2 deletions
diff --git a/deps/v8/src/x64/deoptimizer-x64.cc b/deps/v8/src/x64/deoptimizer-x64.cc index ed6c47bf99..7d6e6d8522 100644 --- a/deps/v8/src/x64/deoptimizer-x64.cc +++ b/deps/v8/src/x64/deoptimizer-x64.cc @@ -203,14 +203,51 @@ void Deoptimizer::DeoptimizeFunction(JSFunction* function) { void Deoptimizer::PatchStackCheckCodeAt(Address pc_after, Code* check_code, Code* replacement_code) { - UNIMPLEMENTED(); + Address call_target_address = pc_after - kIntSize; + ASSERT(check_code->entry() == + Assembler::target_address_at(call_target_address)); + // The stack check code matches the pattern: + // + // cmp rsp, <limit> + // jae ok + // call <stack guard> + // test rax, <loop nesting depth> + // ok: ... + // + // We will patch away the branch so the code is: + // + // cmp rsp, <limit> ;; Not changed + // nop + // nop + // call <on-stack replacment> + // test rax, <loop nesting depth> + // ok: + // + ASSERT(*(call_target_address - 3) == 0x73 && // jae + *(call_target_address - 2) == 0x05 && // offset + *(call_target_address - 1) == 0xe8); // call + *(call_target_address - 3) = 0x90; // nop + *(call_target_address - 2) = 0x90; // nop + Assembler::set_target_address_at(call_target_address, + replacement_code->entry()); } void Deoptimizer::RevertStackCheckCodeAt(Address pc_after, Code* check_code, Code* replacement_code) { - UNIMPLEMENTED(); + Address call_target_address = pc_after - kIntSize; + ASSERT(replacement_code->entry() == + Assembler::target_address_at(call_target_address)); + // Replace the nops from patching (Deoptimizer::PatchStackCheckCode) to + // restore the conditional branch. + ASSERT(*(call_target_address - 3) == 0x90 && // nop + *(call_target_address - 2) == 0x90 && // nop + *(call_target_address - 1) == 0xe8); // call + *(call_target_address - 3) = 0x73; // jae + *(call_target_address - 2) = 0x05; // offset + Assembler::set_target_address_at(call_target_address, + check_code->entry()); } |