// Copyright 2014 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "src/compiler/linkage.h" #include "src/codegen/assembler-inl.h" #include "src/codegen/macro-assembler.h" #include "src/codegen/optimized-compilation-info.h" #include "src/compiler/frame.h" #include "src/compiler/osr.h" #include "src/compiler/pipeline.h" namespace v8 { namespace internal { namespace compiler { namespace { // Offsets from callee to caller frame, in slots. constexpr int kFirstCallerSlotOffset = 1; constexpr int kNoCallerSlotOffset = 0; inline LinkageLocation regloc(Register reg, MachineType type) { return LinkageLocation::ForRegister(reg.code(), type); } inline LinkageLocation regloc(DoubleRegister reg, MachineType type) { return LinkageLocation::ForRegister(reg.code(), type); } } // namespace std::ostream& operator<<(std::ostream& os, const CallDescriptor::Kind& k) { switch (k) { case CallDescriptor::kCallCodeObject: os << "Code"; break; case CallDescriptor::kCallJSFunction: os << "JS"; break; case CallDescriptor::kCallAddress: os << "Addr"; break; #if V8_ENABLE_WEBASSEMBLY case CallDescriptor::kCallWasmCapiFunction: os << "WasmExit"; break; case CallDescriptor::kCallWasmFunction: os << "WasmFunction"; break; case CallDescriptor::kCallWasmImportWrapper: os << "WasmImportWrapper"; break; #endif // V8_ENABLE_WEBASSEMBLY case CallDescriptor::kCallBuiltinPointer: os << "BuiltinPointer"; break; } return os; } std::ostream& operator<<(std::ostream& os, const CallDescriptor& d) { // TODO(svenpanne) Output properties etc. and be less cryptic. return os << d.kind() << ":" << d.debug_name() << ":r" << d.ReturnCount() << "s" << d.ParameterSlotCount() << "i" << d.InputCount() << "f" << d.FrameStateCount(); } MachineSignature* CallDescriptor::GetMachineSignature(Zone* zone) const { size_t param_count = ParameterCount(); size_t return_count = ReturnCount(); MachineType* types = zone->NewArray<MachineType>(param_count + return_count); int current = 0; for (size_t i = 0; i < return_count; ++i) { types[current++] = GetReturnType(i); } for (size_t i = 0; i < param_count; ++i) { types[current++] = GetParameterType(i); } return zone->New<MachineSignature>(return_count, param_count, types); } int CallDescriptor::GetStackParameterDelta( CallDescriptor const* tail_caller) const { // In the IsTailCallForTierUp case, the callee has // identical linkage and runtime arguments to the caller, thus the stack // parameter delta is 0. We don't explicitly pass the runtime arguments as // inputs to the TailCall node, since they already exist on the stack. if (IsTailCallForTierUp()) return 0; // Add padding if necessary before computing the stack parameter delta. int callee_slots_above_sp = AddArgumentPaddingSlots(GetOffsetToReturns()); int tail_caller_slots_above_sp = AddArgumentPaddingSlots(tail_caller->GetOffsetToReturns()); int stack_param_delta = callee_slots_above_sp - tail_caller_slots_above_sp; DCHECK(!ShouldPadArguments(stack_param_delta)); return stack_param_delta; } int CallDescriptor::GetOffsetToFirstUnusedStackSlot() const { int offset = kFirstCallerSlotOffset; for (size_t i = 0; i < InputCount(); ++i) { LinkageLocation operand = GetInputLocation(i); if (!operand.IsRegister()) { DCHECK(operand.IsCallerFrameSlot()); int slot_offset = -operand.GetLocation(); offset = std::max(offset, slot_offset + operand.GetSizeInPointers()); } } return offset; } int CallDescriptor::GetOffsetToReturns() const { // Find the return slot with the least offset relative to the callee. int offset = kNoCallerSlotOffset; for (size_t i = 0; i < ReturnCount(); ++i) { LinkageLocation operand = GetReturnLocation(i); if (!operand.IsRegister()) { DCHECK(operand.IsCallerFrameSlot()); int slot_offset = -operand.GetLocation(); offset = std::min(offset, slot_offset); } } // If there was a return slot, return the offset minus 1 slot. if (offset != kNoCallerSlotOffset) { return offset - 1; } // Otherwise, return the first slot after the parameters area, including // optional padding slots. int last_argument_slot = GetOffsetToFirstUnusedStackSlot() - 1; offset = AddArgumentPaddingSlots(last_argument_slot); DCHECK_IMPLIES(offset == 0, ParameterSlotCount() == 0); return offset; } uint32_t CallDescriptor::GetTaggedParameterSlots() const { uint32_t count = 0; uint32_t first_offset = kMaxInt; for (size_t i = 0; i < InputCount(); ++i) { LinkageLocation operand = GetInputLocation(i); if (!operand.IsRegister() && operand.GetType().IsTagged()) { ++count; // Caller frame slots have negative indices and start at -1. Flip it // back to a positive offset (to be added to the frame's SP to find the // slot). int slot_offset = -operand.GetLocation() - 1; DCHECK_GE(slot_offset, 0); first_offset = std::min(first_offset, static_cast<uint32_t>(slot_offset)); } } if (count > 0) { DCHECK(first_offset != kMaxInt); return (first_offset << 16) | (count & 0xFFFFu); } return 0; } bool CallDescriptor::CanTailCall(const CallDescriptor* callee) const { if (ReturnCount() != callee->ReturnCount()) return false; const int stack_returns_delta = GetOffsetToReturns() - callee->GetOffsetToReturns(); for (size_t i = 0; i < ReturnCount(); ++i) { if (GetReturnLocation(i).IsCallerFrameSlot() && callee->GetReturnLocation(i).IsCallerFrameSlot()) { if (GetReturnLocation(i).AsCallerFrameSlot() + stack_returns_delta != callee->GetReturnLocation(i).AsCallerFrameSlot()) { return false; } } else if (!LinkageLocation::IsSameLocation(GetReturnLocation(i), callee->GetReturnLocation(i))) { return false; } } return true; } // TODO(jkummerow, sigurds): Arguably frame size calculation should be // keyed on code/frame type, not on CallDescriptor kind. Think about a // good way to organize this logic. int CallDescriptor::CalculateFixedFrameSize(CodeKind code_kind) const { switch (kind_) { case kCallJSFunction: return StandardFrameConstants::kFixedSlotCount; case kCallAddress: #if V8_ENABLE_WEBASSEMBLY if (code_kind == CodeKind::C_WASM_ENTRY) { return CWasmEntryFrameConstants::kFixedSlotCount; } #endif // V8_ENABLE_WEBASSEMBLY return CommonFrameConstants::kFixedSlotCountAboveFp + CommonFrameConstants::kCPSlotCount; case kCallCodeObject: case kCallBuiltinPointer: return TypedFrameConstants::kFixedSlotCount; #if V8_ENABLE_WEBASSEMBLY case kCallWasmFunction: case kCallWasmImportWrapper: return WasmFrameConstants::kFixedSlotCount; case kCallWasmCapiFunction: return WasmExitFrameConstants::kFixedSlotCount; #endif // V8_ENABLE_WEBASSEMBLY } UNREACHABLE(); } EncodedCSignature CallDescriptor::ToEncodedCSignature() const { int parameter_count = static_cast<int>(ParameterCount()); EncodedCSignature sig(parameter_count); CHECK_LT(parameter_count, EncodedCSignature::kInvalidParamCount); for (int i = 0; i < parameter_count; ++i) { if (IsFloatingPoint(GetParameterType(i).representation())) { sig.SetFloat(i); } } if (ReturnCount() > 0) { DCHECK_EQ(1, ReturnCount()); if (IsFloatingPoint(GetReturnType(0).representation())) { sig.SetFloat(EncodedCSignature::kReturnIndex); } } return sig; } void CallDescriptor::ComputeParamCounts() const { gp_param_count_ = 0; fp_param_count_ = 0; for (size_t i = 0; i < ParameterCount(); ++i) { if (IsFloatingPoint(GetParameterType(i).representation())) { ++fp_param_count_.value(); } else { ++gp_param_count_.value(); } } } CallDescriptor* Linkage::ComputeIncoming(Zone* zone, OptimizedCompilationInfo* info) { #if V8_ENABLE_WEBASSEMBLY DCHECK(info->IsOptimizing() || info->IsWasm()); #else DCHECK(info->IsOptimizing()); #endif // V8_ENABLE_WEBASSEMBLY if (!info->closure().is_null()) { // If we are compiling a JS function, use a JS call descriptor, // plus the receiver. SharedFunctionInfo shared = info->closure()->shared(); return GetJSCallDescriptor( zone, info->is_osr(), shared.internal_formal_parameter_count_with_receiver(), CallDescriptor::kCanUseRoots); } return nullptr; // TODO(titzer): ? } // static bool Linkage::NeedsFrameStateInput(Runtime::FunctionId function) { switch (function) { // Most runtime functions need a FrameState. A few chosen ones that we know // not to call into arbitrary JavaScript, not to throw, and not to lazily // deoptimize are allowlisted here and can be called without a FrameState. case Runtime::kAbort: case Runtime::kAllocateInOldGeneration: case Runtime::kCreateIterResultObject: case Runtime::kIncBlockCounter: case Runtime::kIsFunction: case Runtime::kNewClosure: case Runtime::kNewClosure_Tenured: case Runtime::kNewFunctionContext: case Runtime::kPushBlockContext: case Runtime::kPushCatchContext: case Runtime::kReThrow: case Runtime::kReThrowWithMessage: case Runtime::kStringEqual: case Runtime::kStringLessThan: case Runtime::kStringLessThanOrEqual: case Runtime::kStringGreaterThan: case Runtime::kStringGreaterThanOrEqual: case Runtime::kToFastProperties: // TODO(conradw): Is it safe? case Runtime::kTraceEnter: case Runtime::kTraceExit: return false; // Some inline intrinsics are also safe to call without a FrameState. case Runtime::kInlineCreateIterResultObject: case Runtime::kInlineIncBlockCounter: case Runtime::kInlineGeneratorClose: case Runtime::kInlineGeneratorGetResumeMode: case Runtime::kInlineCreateJSGeneratorObject: return false; default: break; } // For safety, default to needing a FrameState unless allowlisted. return true; } CallDescriptor* Linkage::GetRuntimeCallDescriptor( Zone* zone, Runtime::FunctionId function_id, int js_parameter_count, Operator::Properties properties, CallDescriptor::Flags flags) { const Runtime::Function* function = Runtime::FunctionForId(function_id); const int return_count = function->result_size; const char* debug_name = function->name; if (!Linkage::NeedsFrameStateInput(function_id)) { flags = static_cast<CallDescriptor::Flags>( flags & ~CallDescriptor::kNeedsFrameState); } return GetCEntryStubCallDescriptor(zone, return_count, js_parameter_count, debug_name, properties, flags); } CallDescriptor* Linkage::GetCEntryStubCallDescriptor( Zone* zone, int return_count, int js_parameter_count, const char* debug_name, Operator::Properties properties, CallDescriptor::Flags flags, StackArgumentOrder stack_order) { const size_t function_count = 1; const size_t num_args_count = 1; const size_t context_count = 1; const size_t parameter_count = function_count + static_cast<size_t>(js_parameter_count) + num_args_count + context_count; LocationSignature::Builder locations(zone, static_cast<size_t>(return_count), static_cast<size_t>(parameter_count)); // Add returns. if (locations.return_count_ > 0) { locations.AddReturn(regloc(kReturnRegister0, MachineType::AnyTagged())); } if (locations.return_count_ > 1) { locations.AddReturn(regloc(kReturnRegister1, MachineType::AnyTagged())); } if (locations.return_count_ > 2) { locations.AddReturn(regloc(kReturnRegister2, MachineType::AnyTagged())); } // All parameters to the runtime call go on the stack. for (int i = 0; i < js_parameter_count; i++) { locations.AddParam(LinkageLocation::ForCallerFrameSlot( i - js_parameter_count, MachineType::AnyTagged())); } // Add runtime function itself. locations.AddParam( regloc(kRuntimeCallFunctionRegister, MachineType::Pointer())); // Add runtime call argument count. locations.AddParam( regloc(kRuntimeCallArgCountRegister, MachineType::Int32())); // Add context. locations.AddParam(regloc(kContextRegister, MachineType::AnyTagged())); // The target for runtime calls is a code object. MachineType target_type = MachineType::AnyTagged(); LinkageLocation target_loc = LinkageLocation::ForAnyRegister(MachineType::AnyTagged()); return zone->New<CallDescriptor>( // -- CallDescriptor::kCallCodeObject, // kind target_type, // target MachineType target_loc, // target location locations.Build(), // location_sig js_parameter_count, // stack_parameter_count properties, // properties kNoCalleeSaved, // callee-saved kNoCalleeSaved, // callee-saved fp flags, // flags debug_name, // debug name stack_order); // stack order } CallDescriptor* Linkage::GetJSCallDescriptor(Zone* zone, bool is_osr, int js_parameter_count, CallDescriptor::Flags flags) { const size_t return_count = 1; const size_t context_count = 1; const size_t new_target_count = 1; const size_t num_args_count = 1; const size_t parameter_count = js_parameter_count + new_target_count + num_args_count + context_count; LocationSignature::Builder locations(zone, return_count, parameter_count); // All JS calls have exactly one return value. locations.AddReturn(regloc(kReturnRegister0, MachineType::AnyTagged())); // All parameters to JS calls go on the stack. for (int i = 0; i < js_parameter_count; i++) { int spill_slot_index = -i - 1; locations.AddParam(LinkageLocation::ForCallerFrameSlot( spill_slot_index, MachineType::AnyTagged())); } // Add JavaScript call new target value. locations.AddParam( regloc(kJavaScriptCallNewTargetRegister, MachineType::AnyTagged())); // Add JavaScript call argument count. locations.AddParam( regloc(kJavaScriptCallArgCountRegister, MachineType::Int32())); // Add context. locations.AddParam(regloc(kContextRegister, MachineType::AnyTagged())); // The target for JS function calls is the JSFunction object. MachineType target_type = MachineType::AnyTagged(); // When entering into an OSR function from unoptimized code the JSFunction // is not in a register, but it is on the stack in the marker spill slot. LinkageLocation target_loc = is_osr ? LinkageLocation::ForSavedCallerFunction() : regloc(kJSFunctionRegister, MachineType::AnyTagged()); return zone->New<CallDescriptor>( // -- CallDescriptor::kCallJSFunction, // kind target_type, // target MachineType target_loc, // target location locations.Build(), // location_sig js_parameter_count, // stack_parameter_count Operator::kNoProperties, // properties kNoCalleeSaved, // callee-saved kNoCalleeSaved, // callee-saved fp flags, // flags "js-call"); // debug name } // TODO(turbofan): cache call descriptors for code stub calls. // TODO(jgruber): Clean up stack parameter count handling. The descriptor // already knows the formal stack parameter count and ideally only additional // stack parameters should be passed into this method. All call-sites should // be audited for correctness (e.g. many used to assume a stack parameter count // of 0). CallDescriptor* Linkage::GetStubCallDescriptor( Zone* zone, const CallInterfaceDescriptor& descriptor, int stack_parameter_count, CallDescriptor::Flags flags, Operator::Properties properties, StubCallMode stub_mode) { const int register_parameter_count = descriptor.GetRegisterParameterCount(); const int js_parameter_count = register_parameter_count + stack_parameter_count; const int context_count = descriptor.HasContextParameter() ? 1 : 0; const size_t parameter_count = static_cast<size_t>(js_parameter_count + context_count); DCHECK_GE(stack_parameter_count, descriptor.GetStackParameterCount()); size_t return_count = descriptor.GetReturnCount(); LocationSignature::Builder locations(zone, return_count, parameter_count); // Add returns. static constexpr Register return_registers[] = { kReturnRegister0, kReturnRegister1, kReturnRegister2}; size_t num_returns = 0; size_t num_fp_returns = 0; for (size_t i = 0; i < locations.return_count_; i++) { MachineType type = descriptor.GetReturnType(static_cast<int>(i)); if (IsFloatingPoint(type.representation())) { DCHECK_LT(num_fp_returns, 1); // Only 1 FP return is supported. locations.AddReturn(regloc(kFPReturnRegister0, type)); num_fp_returns++; } else { DCHECK_LT(num_returns, arraysize(return_registers)); locations.AddReturn(regloc(return_registers[num_returns], type)); num_returns++; } } // Add parameters in registers and on the stack. for (int i = 0; i < js_parameter_count; i++) { if (i < register_parameter_count) { // The first parameters go in registers. // TODO(bbudge) Add floating point registers to the InterfaceDescriptor // and use them for FP types. Currently, this works because on most // platforms, all FP registers are available for use. On ia32, xmm0 is // not allocatable and so we must work around that with platform-specific // descriptors, adjusting the GP register set to avoid eax, which has // register code 0. Register reg = descriptor.GetRegisterParameter(i); MachineType type = descriptor.GetParameterType(i); locations.AddParam(regloc(reg, type)); } else { // The rest of the parameters go on the stack. int stack_slot = i - register_parameter_count - stack_parameter_count; locations.AddParam(LinkageLocation::ForCallerFrameSlot( stack_slot, i < descriptor.GetParameterCount() ? descriptor.GetParameterType(i) : MachineType::AnyTagged())); } } // Add context. if (context_count) { locations.AddParam(regloc(kContextRegister, MachineType::AnyTagged())); } // The target for stub calls depends on the requested mode. CallDescriptor::Kind kind; MachineType target_type; switch (stub_mode) { case StubCallMode::kCallCodeObject: kind = CallDescriptor::kCallCodeObject; target_type = MachineType::AnyTagged(); break; #if V8_ENABLE_WEBASSEMBLY case StubCallMode::kCallWasmRuntimeStub: kind = CallDescriptor::kCallWasmFunction; target_type = MachineType::Pointer(); break; #endif // V8_ENABLE_WEBASSEMBLY case StubCallMode::kCallBuiltinPointer: kind = CallDescriptor::kCallBuiltinPointer; target_type = MachineType::AnyTagged(); break; } RegList allocatable_registers = descriptor.allocatable_registers(); RegList callee_saved_registers = kNoCalleeSaved; if (descriptor.CalleeSaveRegisters()) { callee_saved_registers = allocatable_registers; DCHECK(callee_saved_registers); } LinkageLocation target_loc = LinkageLocation::ForAnyRegister(target_type); return zone->New<CallDescriptor>( // -- kind, // kind target_type, // target MachineType target_loc, // target location locations.Build(), // location_sig stack_parameter_count, // stack_parameter_count properties, // properties callee_saved_registers, // callee-saved registers kNoCalleeSaved, // callee-saved fp CallDescriptor::kCanUseRoots | flags, // flags descriptor.DebugName(), // debug name descriptor.GetStackArgumentOrder(), // stack order #if V8_ENABLE_WEBASSEMBLY nullptr, // wasm function signature #endif allocatable_registers); } // static CallDescriptor* Linkage::GetBytecodeDispatchCallDescriptor( Zone* zone, const CallInterfaceDescriptor& descriptor, int stack_parameter_count) { const int register_parameter_count = descriptor.GetRegisterParameterCount(); const int parameter_count = register_parameter_count + stack_parameter_count; DCHECK_EQ(descriptor.GetReturnCount(), 1); LocationSignature::Builder locations(zone, 1, parameter_count); locations.AddReturn(regloc(kReturnRegister0, descriptor.GetReturnType(0))); // Add parameters in registers and on the stack. for (int i = 0; i < parameter_count; i++) { if (i < register_parameter_count) { // The first parameters go in registers. Register reg = descriptor.GetRegisterParameter(i); MachineType type = descriptor.GetParameterType(i); locations.AddParam(regloc(reg, type)); } else { // The rest of the parameters go on the stack. int stack_slot = i - register_parameter_count - stack_parameter_count; locations.AddParam(LinkageLocation::ForCallerFrameSlot( stack_slot, MachineType::AnyTagged())); } } // The target for interpreter dispatches is a code entry address. MachineType target_type = MachineType::Pointer(); LinkageLocation target_loc = LinkageLocation::ForAnyRegister(target_type); const CallDescriptor::Flags kFlags = CallDescriptor::kCanUseRoots | CallDescriptor::kFixedTargetRegister; return zone->New<CallDescriptor>( // -- CallDescriptor::kCallAddress, // kind target_type, // target MachineType target_loc, // target location locations.Build(), // location_sig stack_parameter_count, // stack_parameter_count Operator::kNoProperties, // properties kNoCalleeSaved, // callee-saved registers kNoCalleeSaved, // callee-saved fp kFlags, // flags descriptor.DebugName()); } LinkageLocation Linkage::GetOsrValueLocation(int index) const { CHECK(incoming_->IsJSFunctionCall()); int parameter_count = static_cast<int>(incoming_->JSParameterCount() - 1); int first_stack_slot = OsrHelper::FirstStackSlotIndex(parameter_count); if (index == kOsrContextSpillSlotIndex) { // Context. Use the parameter location of the context spill slot. // Parameter (arity + 2) is special for the context of the function frame. // >> context_index = target + receiver + params + new_target + #args int context_index = 1 + 1 + parameter_count + 1 + 1; return incoming_->GetInputLocation(context_index); } else if (index >= first_stack_slot) { // Local variable stored in this (callee) stack. int spill_index = index - first_stack_slot + StandardFrameConstants::kFixedSlotCount; return LinkageLocation::ForCalleeFrameSlot(spill_index, MachineType::AnyTagged()); } else { // Parameter. Use the assigned location from the incoming call descriptor. int parameter_index = 1 + index; // skip index 0, which is the target. return incoming_->GetInputLocation(parameter_index); } } namespace { inline bool IsTaggedReg(const LinkageLocation& loc, Register reg) { return loc.IsRegister() && loc.AsRegister() == reg.code() && loc.GetType().representation() == MachineRepresentation::kTaggedPointer; } } // namespace bool Linkage::ParameterHasSecondaryLocation(int index) const { // TODO(titzer): this should be configurable, not call-type specific. if (incoming_->IsJSFunctionCall()) { LinkageLocation loc = GetParameterLocation(index); return IsTaggedReg(loc, kJSFunctionRegister) || IsTaggedReg(loc, kContextRegister); } #if V8_ENABLE_WEBASSEMBLY if (incoming_->IsWasmFunctionCall()) { LinkageLocation loc = GetParameterLocation(index); return IsTaggedReg(loc, kWasmInstanceRegister); } #endif // V8_ENABLE_WEBASSEMBLY return false; } LinkageLocation Linkage::GetParameterSecondaryLocation(int index) const { // TODO(titzer): these constants are necessary due to offset/slot# mismatch static const int kJSContextSlot = 2 + StandardFrameConstants::kCPSlotCount; static const int kJSFunctionSlot = 3 + StandardFrameConstants::kCPSlotCount; DCHECK(ParameterHasSecondaryLocation(index)); LinkageLocation loc = GetParameterLocation(index); // TODO(titzer): this should be configurable, not call-type specific. if (incoming_->IsJSFunctionCall()) { if (IsTaggedReg(loc, kJSFunctionRegister)) { return LinkageLocation::ForCalleeFrameSlot(kJSFunctionSlot, MachineType::AnyTagged()); } else { DCHECK(IsTaggedReg(loc, kContextRegister)); return LinkageLocation::ForCalleeFrameSlot(kJSContextSlot, MachineType::AnyTagged()); } } #if V8_ENABLE_WEBASSEMBLY static const int kWasmInstanceSlot = 3 + StandardFrameConstants::kCPSlotCount; if (incoming_->IsWasmFunctionCall()) { DCHECK(IsTaggedReg(loc, kWasmInstanceRegister)); return LinkageLocation::ForCalleeFrameSlot(kWasmInstanceSlot, MachineType::AnyTagged()); } #endif // V8_ENABLE_WEBASSEMBLY UNREACHABLE(); } } // namespace compiler } // namespace internal } // namespace v8