// Copyright 2006-2008 the V8 project authors. All rights reserved. // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following // disclaimer in the documentation and/or other materials provided // with the distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #include "v8.h" #include "bootstrapper.h" #include "codegen-inl.h" #include "debug.h" #include "runtime.h" namespace v8 { namespace internal { DECLARE_bool(debug_code); DECLARE_bool(optimize_locals); // Give alias names to registers Register cp = { 8 }; // JavaScript context pointer Register pp = { 10 }; // parameter pointer MacroAssembler::MacroAssembler(void* buffer, int size) : Assembler(buffer, size), unresolved_(0), generating_stub_(false), allow_stub_calls_(true) { } // We always generate arm code, never thumb code, even if V8 is compiled to // thumb, so we require inter-working support #if defined(__thumb__) && !defined(__THUMB_INTERWORK__) #error "flag -mthumb-interwork missing" #endif // We do not support thumb inter-working with an arm architecture not supporting // the blx instruction (below v5t) #if defined(__THUMB_INTERWORK__) #if !defined(__ARM_ARCH_5T__) && !defined(__ARM_ARCH_5TE__) // add tests for other versions above v5t as required #error "for thumb inter-working we require architecture v5t or above" #endif #endif // Using blx may yield better code, so use it when required or when available #if defined(__THUMB_INTERWORK__) || defined(__ARM_ARCH_5__) #define USE_BLX 1 #endif // Using bx does not yield better code, so use it only when required #if defined(__THUMB_INTERWORK__) #define USE_BX 1 #endif void MacroAssembler::Jump(Register target, Condition cond) { #if USE_BX bx(target, cond); #else mov(pc, Operand(target), LeaveCC, cond); #endif } void MacroAssembler::Jump(intptr_t target, RelocMode rmode, Condition cond) { #if USE_BX mov(ip, Operand(target, rmode), LeaveCC, cond); bx(ip, cond); #else mov(pc, Operand(target, rmode), LeaveCC, cond); #endif } void MacroAssembler::Jump(byte* target, RelocMode rmode, Condition cond) { ASSERT(!is_code_target(rmode)); Jump(reinterpret_cast(target), rmode, cond); } void MacroAssembler::Jump(Handle code, RelocMode rmode, Condition cond) { ASSERT(is_code_target(rmode)); // 'code' is always generated ARM code, never THUMB code Jump(reinterpret_cast(code.location()), rmode, cond); } void MacroAssembler::Call(Register target, Condition cond) { #if USE_BLX blx(target, cond); #else // set lr for return at current pc + 8 mov(lr, Operand(pc), LeaveCC, cond); mov(pc, Operand(target), LeaveCC, cond); #endif } void MacroAssembler::Call(intptr_t target, RelocMode rmode, Condition cond) { #if !defined(__arm__) if (rmode == runtime_entry) { mov(r2, Operand(target, rmode), LeaveCC, cond); // Set lr for return at current pc + 8. mov(lr, Operand(pc), LeaveCC, cond); // Emit a ldr pc, [pc + offset of target in constant pool]. // Notify the simulator of the transition to C code. swi(assembler::arm::call_rt_r2); } else { // set lr for return at current pc + 8 mov(lr, Operand(pc), LeaveCC, cond); // emit a ldr pc, [pc + offset of target in constant pool] mov(pc, Operand(target, rmode), LeaveCC, cond); } #else // Set lr for return at current pc + 8. mov(lr, Operand(pc), LeaveCC, cond); // Emit a ldr pc, [pc + offset of target in constant pool]. mov(pc, Operand(target, rmode), LeaveCC, cond); #endif // !defined(__arm__) // If USE_BLX is defined, we could emit a 'mov ip, target', followed by a // 'blx ip'; however, the code would not be shorter than the above sequence // and the target address of the call would be referenced by the first // instruction rather than the second one, which would make it harder to patch // (two instructions before the return address, instead of one). ASSERT(kTargetAddrToReturnAddrDist == sizeof(Instr)); } void MacroAssembler::Call(byte* target, RelocMode rmode, Condition cond) { ASSERT(!is_code_target(rmode)); Call(reinterpret_cast(target), rmode, cond); } void MacroAssembler::Call(Handle code, RelocMode rmode, Condition cond) { ASSERT(is_code_target(rmode)); // 'code' is always generated ARM code, never THUMB code Call(reinterpret_cast(code.location()), rmode, cond); } void MacroAssembler::Ret() { #if USE_BX bx(lr); #else mov(pc, Operand(lr)); #endif } // Will clobber 4 registers: object, offset, scratch, ip. The // register 'object' contains a heap object pointer. The heap object // tag is shifted away. void MacroAssembler::RecordWrite(Register object, Register offset, Register scratch) { // This is how much we shift the remembered set bit offset to get the // offset of the word in the remembered set. We divide by kBitsPerInt (32, // shift right 5) and then multiply by kIntSize (4, shift left 2). const int kRSetWordShift = 3; Label fast, done; // First, test that the object is not in the new space. We cannot set // remembered set bits in the new space. // object: heap object pointer (with tag) // offset: offset to store location from the object and_(scratch, object, Operand(Heap::NewSpaceMask())); cmp(scratch, Operand(ExternalReference::new_space_start())); b(eq, &done); // Compute the bit offset in the remembered set. // object: heap object pointer (with tag) // offset: offset to store location from the object mov(ip, Operand(Page::kPageAlignmentMask)); // load mask only once and_(scratch, object, Operand(ip)); // offset into page of the object add(offset, scratch, Operand(offset)); // add offset into the object mov(offset, Operand(offset, LSR, kObjectAlignmentBits)); // Compute the page address from the heap object pointer. // object: heap object pointer (with tag) // offset: bit offset of store position in the remembered set bic(object, object, Operand(ip)); // If the bit offset lies beyond the normal remembered set range, it is in // the extra remembered set area of a large object. // object: page start // offset: bit offset of store position in the remembered set cmp(offset, Operand(Page::kPageSize / kPointerSize)); b(lt, &fast); // Adjust the bit offset to be relative to the start of the extra // remembered set and the start address to be the address of the extra // remembered set. sub(offset, offset, Operand(Page::kPageSize / kPointerSize)); // Load the array length into 'scratch' and multiply by four to get the // size in bytes of the elements. ldr(scratch, MemOperand(object, Page::kObjectStartOffset + FixedArray::kLengthOffset)); mov(scratch, Operand(scratch, LSL, kObjectAlignmentBits)); // Add the page header (including remembered set), array header, and array // body size to the page address. add(object, object, Operand(Page::kObjectStartOffset + Array::kHeaderSize)); add(object, object, Operand(scratch)); bind(&fast); // Get address of the rset word. // object: start of the remembered set (page start for the fast case) // offset: bit offset of store position in the remembered set bic(scratch, offset, Operand(kBitsPerInt - 1)); // clear the bit offset add(object, object, Operand(scratch, LSR, kRSetWordShift)); // Get bit offset in the rset word. // object: address of remembered set word // offset: bit offset of store position and_(offset, offset, Operand(kBitsPerInt - 1)); ldr(scratch, MemOperand(object)); mov(ip, Operand(1)); orr(scratch, scratch, Operand(ip, LSL, offset)); str(scratch, MemOperand(object)); bind(&done); } void MacroAssembler::EnterJSFrame(int argc) { // Generate code entering a JS function called from a JS function // stack: receiver, arguments // r0: number of arguments (not including function, nor receiver) // r1: preserved // sp: stack pointer // fp: frame pointer // cp: callee's context // pp: caller's parameter pointer // lr: return address // compute parameter pointer before making changes // ip = sp + kPointerSize*(args_len+1); // +1 for receiver add(ip, sp, Operand(r0, LSL, kPointerSizeLog2)); add(ip, ip, Operand(kPointerSize)); // push extra parameters if we don't have enough // (this can only happen if argc > 0 to begin with) if (argc > 0) { Label loop, done; // assume enough arguments to be the most common case sub(r2, r0, Operand(argc), SetCC); // number of missing arguments b(ge, &done); // enough arguments // not enough arguments mov(r3, Operand(Factory::undefined_value())); bind(&loop); push(r3); add(r2, r2, Operand(1), SetCC); b(lt, &loop); bind(&done); } mov(r3, Operand(r0)); // args_len to be saved mov(r2, Operand(cp)); // context to be saved // push in reverse order: context (r2), args_len (r3), caller_pp, caller_fp, // sp_on_exit (ip == pp, may be patched on exit), return address stm(db_w, sp, r2.bit() | r3.bit() | pp.bit() | fp.bit() | ip.bit() | lr.bit()); // Setup new frame pointer. add(fp, sp, Operand(-StandardFrameConstants::kContextOffset)); mov(pp, Operand(ip)); // setup new parameter pointer mov(r0, Operand(0)); // spare slot to store caller code object during GC push(r0); // r1: preserved } void MacroAssembler::ExitJSFrame(ExitJSFlag flag) { // r0: result // sp: stack pointer // fp: frame pointer // pp: parameter pointer if (flag == DO_NOT_RETURN) { add(r3, fp, Operand(JavaScriptFrameConstants::kSavedRegistersOffset)); } if (flag == DO_NOT_RETURN) { // restore sp as caller_sp (not as pp) str(r3, MemOperand(fp, JavaScriptFrameConstants::kSPOnExitOffset)); } if (flag == DO_NOT_RETURN && generating_stub()) { // If we're generating a stub, we need to preserve the link // register to be able to return to the place the stub was called // from. mov(ip, Operand(lr)); } mov(sp, Operand(fp)); // respect ABI stack constraint ldm(ia, sp, pp.bit() | fp.bit() | sp.bit() | ((flag == RETURN) ? pc.bit() : lr.bit())); if (flag == DO_NOT_RETURN && generating_stub()) { // Return to the place where the stub was called without // clobbering the value of the link register. mov(pc, Operand(ip)); } // r0: result // sp: points to function arg (if return) or to last arg (if no return) // fp: restored frame pointer // pp: restored parameter pointer } void MacroAssembler::InvokePrologue(const ParameterCount& expected, const ParameterCount& actual, Handle code_constant, Register code_reg, Label* done, InvokeFlag flag) { if (actual.is_immediate()) { mov(r0, Operand(actual.immediate())); // Push the number of arguments. } else { if (!actual.reg().is(r0)) { mov(r0, Operand(actual.reg())); } } } void MacroAssembler::InvokeCode(Register code, const ParameterCount& expected, const ParameterCount& actual, InvokeFlag flag) { Label done; InvokePrologue(expected, actual, Handle::null(), code, &done, flag); if (flag == CALL_FUNCTION) { Call(code); } else { ASSERT(flag == JUMP_FUNCTION); Jump(code); } // Continue here if InvokePrologue does handle the invocation due to // mismatched parameter counts. bind(&done); } void MacroAssembler::InvokeCode(Handle code, const ParameterCount& expected, const ParameterCount& actual, RelocMode rmode, InvokeFlag flag) { Label done; InvokePrologue(expected, actual, code, no_reg, &done, flag); if (flag == CALL_FUNCTION) { Call(code, rmode); } else { Jump(code, rmode); } // Continue here if InvokePrologue does handle the invocation due to // mismatched parameter counts. bind(&done); } void MacroAssembler::InvokeFunction(Register fun, const ParameterCount& actual, InvokeFlag flag) { // Contract with called JS functions requires that function is passed in r1. ASSERT(fun.is(r1)); Register code_reg = r3; Register expected_reg = r2; // Make sure that the code and expected registers do not collide with the // actual register being passed in. if (actual.is_reg()) { if (actual.reg().is(code_reg)) { code_reg = r4; } else if (actual.reg().is(expected_reg)) { expected_reg = r4; } } ldr(code_reg, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset)); ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset)); ldr(expected_reg, FieldMemOperand(code_reg, SharedFunctionInfo::kFormalParameterCountOffset)); ldr(code_reg, MemOperand(code_reg, SharedFunctionInfo::kCodeOffset - kHeapObjectTag)); add(code_reg, code_reg, Operand(Code::kHeaderSize - kHeapObjectTag)); ParameterCount expected(expected_reg); InvokeCode(code_reg, expected, actual, flag); } void MacroAssembler::SaveRegistersToMemory(RegList regs) { ASSERT((regs & ~kJSCallerSaved) == 0); // Copy the content of registers to memory location. for (int i = 0; i < kNumJSCallerSaved; i++) { int r = JSCallerSavedCode(i); if ((regs & (1 << r)) != 0) { Register reg = { r }; mov(ip, Operand(ExternalReference(Debug_Address::Register(i)))); str(reg, MemOperand(ip)); } } } void MacroAssembler::RestoreRegistersFromMemory(RegList regs) { ASSERT((regs & ~kJSCallerSaved) == 0); // Copy the content of memory location to registers. for (int i = kNumJSCallerSaved; --i >= 0;) { int r = JSCallerSavedCode(i); if ((regs & (1 << r)) != 0) { Register reg = { r }; mov(ip, Operand(ExternalReference(Debug_Address::Register(i)))); ldr(reg, MemOperand(ip)); } } } void MacroAssembler::CopyRegistersFromMemoryToStack(Register base, RegList regs) { ASSERT((regs & ~kJSCallerSaved) == 0); // Copy the content of the memory location to the stack and adjust base. for (int i = kNumJSCallerSaved; --i >= 0;) { int r = JSCallerSavedCode(i); if ((regs & (1 << r)) != 0) { mov(ip, Operand(ExternalReference(Debug_Address::Register(i)))); ldr(ip, MemOperand(ip)); str(ip, MemOperand(base, 4, NegPreIndex)); } } } void MacroAssembler::CopyRegistersFromStackToMemory(Register base, Register scratch, RegList regs) { ASSERT((regs & ~kJSCallerSaved) == 0); // Copy the content of the stack to the memory location and adjust base. for (int i = 0; i < kNumJSCallerSaved; i++) { int r = JSCallerSavedCode(i); if ((regs & (1 << r)) != 0) { mov(ip, Operand(ExternalReference(Debug_Address::Register(i)))); ldr(scratch, MemOperand(base, 4, PostIndex)); str(scratch, MemOperand(ip)); } } } void MacroAssembler::PushTryHandler(CodeLocation try_location, HandlerType type) { ASSERT(StackHandlerConstants::kSize == 6 * kPointerSize); // adjust this code // The pc (return address) is passed in register lr. if (try_location == IN_JAVASCRIPT) { stm(db_w, sp, pp.bit() | fp.bit() | lr.bit()); if (type == TRY_CATCH_HANDLER) { mov(r3, Operand(StackHandler::TRY_CATCH)); } else { mov(r3, Operand(StackHandler::TRY_FINALLY)); } push(r3); // state mov(r3, Operand(ExternalReference(Top::k_handler_address))); ldr(r1, MemOperand(r3)); push(r1); // next sp str(sp, MemOperand(r3)); // chain handler mov(r0, Operand(Smi::FromInt(StackHandler::kCodeNotPresent))); // new TOS push(r0); } else { // Must preserve r0-r3, r5-r7 are available. ASSERT(try_location == IN_JS_ENTRY); // The parameter pointer is meaningless here and fp does not point to a JS // frame. So we save NULL for both pp and fp. We expect the code throwing an // exception to check fp before dereferencing it to restore the context. mov(pp, Operand(0)); // set pp to NULL mov(ip, Operand(0)); // to save a NULL fp stm(db_w, sp, pp.bit() | ip.bit() | lr.bit()); mov(r6, Operand(StackHandler::ENTRY)); push(r6); // state mov(r7, Operand(ExternalReference(Top::k_handler_address))); ldr(r6, MemOperand(r7)); push(r6); // next sp str(sp, MemOperand(r7)); // chain handler mov(r5, Operand(Smi::FromInt(StackHandler::kCodeNotPresent))); // new TOS push(r5); // flush TOS } } Register MacroAssembler::CheckMaps(JSObject* object, Register object_reg, JSObject* holder, Register holder_reg, Register scratch, Label* miss) { // Make sure there's no overlap between scratch and the other // registers. ASSERT(!scratch.is(object_reg) && !scratch.is(holder_reg)); // Keep track of the current object in register reg. Register reg = object_reg; int depth = 1; // Check the maps in the prototype chain. // Traverse the prototype chain from the object and do map checks. while (object != holder) { depth++; // Only global objects and objects that do not require access // checks are allowed in stubs. ASSERT(object->IsJSGlobalObject() || !object->IsAccessCheckNeeded()); // Get the map of the current object. ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset)); cmp(scratch, Operand(Handle(object->map()))); // Branch on the result of the map check. b(ne, miss); // Check access rights to the global object. This has to happen // after the map check so that we know that the object is // actually a global object. if (object->IsJSGlobalObject()) { CheckAccessGlobal(reg, scratch, miss); // Restore scratch register to be the map of the object. In the // new space case below, we load the prototype from the map in // the scratch register. ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset)); } reg = holder_reg; // from now the object is in holder_reg JSObject* prototype = JSObject::cast(object->GetPrototype()); if (Heap::InNewSpace(prototype)) { // The prototype is in new space; we cannot store a reference // to it in the code. Load it from the map. ldr(reg, FieldMemOperand(scratch, Map::kPrototypeOffset)); } else { // The prototype is in old space; load it directly. mov(reg, Operand(Handle(prototype))); } // Go to the next object in the prototype chain. object = prototype; } // Check the holder map. ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset)); cmp(scratch, Operand(Handle(object->map()))); b(ne, miss); // Log the check depth. LOG(IntEvent("check-maps-depth", depth)); // Perform security check for access to the global object and return // the holder register. ASSERT(object == holder); ASSERT(object->IsJSGlobalObject() || !object->IsAccessCheckNeeded()); if (object->IsJSGlobalObject()) { CheckAccessGlobal(reg, scratch, miss); } return reg; } void MacroAssembler::CheckAccessGlobal(Register holder_reg, Register scratch, Label* miss) { ASSERT(!holder_reg.is(scratch)); // Load the security context. mov(scratch, Operand(Top::security_context_address())); ldr(scratch, MemOperand(scratch)); // In debug mode, make sure the security context is set. if (kDebug) { cmp(scratch, Operand(0)); Check(ne, "we should not have an empty security context"); } // Load the global object of the security context. int offset = Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize; ldr(scratch, FieldMemOperand(scratch, offset)); // Check that the security token in the calling global object is // compatible with the security token in the receiving global // object. ldr(scratch, FieldMemOperand(scratch, JSGlobalObject::kSecurityTokenOffset)); ldr(ip, FieldMemOperand(holder_reg, JSGlobalObject::kSecurityTokenOffset)); cmp(scratch, Operand(ip)); b(ne, miss); } void MacroAssembler::CallStub(CodeStub* stub) { ASSERT(allow_stub_calls()); // stub calls are not allowed in some stubs Call(stub->GetCode(), code_target); } void MacroAssembler::CallJSExitStub(CodeStub* stub) { ASSERT(allow_stub_calls()); // stub calls are not allowed in some stubs Call(stub->GetCode(), exit_js_frame); } void MacroAssembler::StubReturn(int argc) { ASSERT(argc >= 1 && generating_stub()); if (argc > 1) add(sp, sp, Operand((argc - 1) * kPointerSize)); Ret(); } void MacroAssembler::CallRuntime(Runtime::Function* f, int num_arguments) { // All parameters are on the stack. r0 has the return value after call. // Either the expected number of arguments is unknown, or the actual // number of arguments match the expectation. ASSERT(f->nargs < 0 || f->nargs == num_arguments); Runtime::FunctionId function_id = static_cast(f->stub_id); RuntimeStub stub(function_id, num_arguments); CallStub(&stub); } void MacroAssembler::CallRuntime(Runtime::FunctionId fid, int num_arguments) { CallRuntime(Runtime::FunctionForId(fid), num_arguments); } void MacroAssembler::TailCallRuntime(const ExternalReference& ext, int num_arguments) { // TODO(1236192): Most runtime routines don't need the number of // arguments passed in because it is constant. At some point we // should remove this need and make the runtime routine entry code // smarter. mov(r0, Operand(num_arguments)); JumpToBuiltin(ext); } void MacroAssembler::JumpToBuiltin(const ExternalReference& builtin) { #if defined(__thumb__) // Thumb mode builtin. ASSERT((reinterpret_cast(builtin.address()) & 1) == 1); #endif mov(r1, Operand(builtin)); CEntryStub stub; Jump(stub.GetCode(), code_target); } void MacroAssembler::InvokeBuiltin(const char* name, int argc, InvokeJSFlags flags) { Handle symbol = Factory::LookupAsciiSymbol(name); Object* object = Top::security_context_builtins()->GetProperty(*symbol); bool unresolved = true; Code* code = Builtins::builtin(Builtins::Illegal); if (object->IsJSFunction()) { Handle function(JSFunction::cast(object)); if (function->is_compiled() || CompileLazy(function, CLEAR_EXCEPTION)) { code = function->code(); unresolved = false; } } if (flags == CALL_JS) { Call(Handle(code), code_target); } else { ASSERT(flags == JUMP_JS); Jump(Handle(code), code_target); } if (unresolved) { uint32_t flags = Bootstrapper::FixupFlagsArgumentsCount::encode(argc) | Bootstrapper::FixupFlagsIsPCRelative::encode(false); Unresolved entry = { pc_offset() - sizeof(Instr), flags, name }; unresolved_.Add(entry); } } void MacroAssembler::Assert(Condition cc, const char* msg) { if (FLAG_debug_code) Check(cc, msg); } void MacroAssembler::Check(Condition cc, const char* msg) { Label L; b(cc, &L); Abort(msg); // will not return here bind(&L); } void MacroAssembler::Abort(const char* msg) { // We want to pass the msg string like a smi to avoid GC // problems, however msg is not guaranteed to be aligned // properly. Instead, we pass an aligned pointer that is // a proper v8 smi, but also pass the aligment difference // from the real pointer as a smi. intptr_t p1 = reinterpret_cast(msg); intptr_t p0 = (p1 & ~kSmiTagMask) + kSmiTag; ASSERT(reinterpret_cast(p0)->IsSmi()); #ifdef DEBUG if (msg != NULL) { RecordComment("Abort message: "); RecordComment(msg); } #endif mov(r0, Operand(p0)); push(r0); mov(r0, Operand(Smi::FromInt(p1 - p0))); push(r0); CallRuntime(Runtime::kAbort, 2); // will not return here } } } // namespace v8::internal