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Diffstat (limited to 'compiler/utils/assembler.h')
| -rw-r--r-- | compiler/utils/assembler.h | 460 |
1 files changed, 460 insertions, 0 deletions
diff --git a/compiler/utils/assembler.h b/compiler/utils/assembler.h new file mode 100644 index 0000000000..c9be4edbf8 --- /dev/null +++ b/compiler/utils/assembler.h @@ -0,0 +1,460 @@ +/* + * Copyright (C) 2011 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef ART_COMPILER_UTILS_ASSEMBLER_H_ +#define ART_COMPILER_UTILS_ASSEMBLER_H_ + +#include <vector> + +#include "base/logging.h" +#include "base/macros.h" +#include "arm/constants_arm.h" +#include "mips/constants_mips.h" +#include "x86/constants_x86.h" +#include "instruction_set.h" +#include "managed_register.h" +#include "memory_region.h" +#include "offsets.h" + +namespace art { + +class Assembler; +class AssemblerBuffer; +class AssemblerFixup; + +namespace arm { + class ArmAssembler; +} +namespace mips { + class MipsAssembler; +} +namespace x86 { + class X86Assembler; +} + +class Label { + public: + Label() : position_(0) {} + + ~Label() { + // Assert if label is being destroyed with unresolved branches pending. + CHECK(!IsLinked()); + } + + // Returns the position for bound and linked labels. Cannot be used + // for unused labels. + int Position() const { + CHECK(!IsUnused()); + return IsBound() ? -position_ - kPointerSize : position_ - kPointerSize; + } + + int LinkPosition() const { + CHECK(IsLinked()); + return position_ - kWordSize; + } + + bool IsBound() const { return position_ < 0; } + bool IsUnused() const { return position_ == 0; } + bool IsLinked() const { return position_ > 0; } + + private: + int position_; + + void Reinitialize() { + position_ = 0; + } + + void BindTo(int position) { + CHECK(!IsBound()); + position_ = -position - kPointerSize; + CHECK(IsBound()); + } + + void LinkTo(int position) { + CHECK(!IsBound()); + position_ = position + kPointerSize; + CHECK(IsLinked()); + } + + friend class arm::ArmAssembler; + friend class mips::MipsAssembler; + friend class x86::X86Assembler; + + DISALLOW_COPY_AND_ASSIGN(Label); +}; + + +// Assembler fixups are positions in generated code that require processing +// after the code has been copied to executable memory. This includes building +// relocation information. +class AssemblerFixup { + public: + virtual void Process(const MemoryRegion& region, int position) = 0; + virtual ~AssemblerFixup() {} + + private: + AssemblerFixup* previous_; + int position_; + + AssemblerFixup* previous() const { return previous_; } + void set_previous(AssemblerFixup* previous) { previous_ = previous; } + + int position() const { return position_; } + void set_position(int position) { position_ = position; } + + friend class AssemblerBuffer; +}; + +// Parent of all queued slow paths, emitted during finalization +class SlowPath { + public: + SlowPath() : next_(NULL) {} + virtual ~SlowPath() {} + + Label* Continuation() { return &continuation_; } + Label* Entry() { return &entry_; } + // Generate code for slow path + virtual void Emit(Assembler *sp_asm) = 0; + + protected: + // Entry branched to by fast path + Label entry_; + // Optional continuation that is branched to at the end of the slow path + Label continuation_; + // Next in linked list of slow paths + SlowPath *next_; + + private: + friend class AssemblerBuffer; + DISALLOW_COPY_AND_ASSIGN(SlowPath); +}; + +class AssemblerBuffer { + public: + AssemblerBuffer(); + ~AssemblerBuffer(); + + // Basic support for emitting, loading, and storing. + template<typename T> void Emit(T value) { + CHECK(HasEnsuredCapacity()); + *reinterpret_cast<T*>(cursor_) = value; + cursor_ += sizeof(T); + } + + template<typename T> T Load(size_t position) { + CHECK_LE(position, Size() - static_cast<int>(sizeof(T))); + return *reinterpret_cast<T*>(contents_ + position); + } + + template<typename T> void Store(size_t position, T value) { + CHECK_LE(position, Size() - static_cast<int>(sizeof(T))); + *reinterpret_cast<T*>(contents_ + position) = value; + } + + // Emit a fixup at the current location. + void EmitFixup(AssemblerFixup* fixup) { + fixup->set_previous(fixup_); + fixup->set_position(Size()); + fixup_ = fixup; + } + + void EnqueueSlowPath(SlowPath* slowpath) { + if (slow_path_ == NULL) { + slow_path_ = slowpath; + } else { + SlowPath* cur = slow_path_; + for ( ; cur->next_ != NULL ; cur = cur->next_) {} + cur->next_ = slowpath; + } + } + + void EmitSlowPaths(Assembler* sp_asm) { + SlowPath* cur = slow_path_; + SlowPath* next = NULL; + slow_path_ = NULL; + for ( ; cur != NULL ; cur = next) { + cur->Emit(sp_asm); + next = cur->next_; + delete cur; + } + } + + // Get the size of the emitted code. + size_t Size() const { + CHECK_GE(cursor_, contents_); + return cursor_ - contents_; + } + + byte* contents() const { return contents_; } + + // Copy the assembled instructions into the specified memory block + // and apply all fixups. + void FinalizeInstructions(const MemoryRegion& region); + + // To emit an instruction to the assembler buffer, the EnsureCapacity helper + // must be used to guarantee that the underlying data area is big enough to + // hold the emitted instruction. Usage: + // + // AssemblerBuffer buffer; + // AssemblerBuffer::EnsureCapacity ensured(&buffer); + // ... emit bytes for single instruction ... + +#ifndef NDEBUG + + class EnsureCapacity { + public: + explicit EnsureCapacity(AssemblerBuffer* buffer) { + if (buffer->cursor() >= buffer->limit()) { + buffer->ExtendCapacity(); + } + // In debug mode, we save the assembler buffer along with the gap + // size before we start emitting to the buffer. This allows us to + // check that any single generated instruction doesn't overflow the + // limit implied by the minimum gap size. + buffer_ = buffer; + gap_ = ComputeGap(); + // Make sure that extending the capacity leaves a big enough gap + // for any kind of instruction. + CHECK_GE(gap_, kMinimumGap); + // Mark the buffer as having ensured the capacity. + CHECK(!buffer->HasEnsuredCapacity()); // Cannot nest. + buffer->has_ensured_capacity_ = true; + } + + ~EnsureCapacity() { + // Unmark the buffer, so we cannot emit after this. + buffer_->has_ensured_capacity_ = false; + // Make sure the generated instruction doesn't take up more + // space than the minimum gap. + int delta = gap_ - ComputeGap(); + CHECK_LE(delta, kMinimumGap); + } + + private: + AssemblerBuffer* buffer_; + int gap_; + + int ComputeGap() { return buffer_->Capacity() - buffer_->Size(); } + }; + + bool has_ensured_capacity_; + bool HasEnsuredCapacity() const { return has_ensured_capacity_; } + +#else + + class EnsureCapacity { + public: + explicit EnsureCapacity(AssemblerBuffer* buffer) { + if (buffer->cursor() >= buffer->limit()) buffer->ExtendCapacity(); + } + }; + + // When building the C++ tests, assertion code is enabled. To allow + // asserting that the user of the assembler buffer has ensured the + // capacity needed for emitting, we add a dummy method in non-debug mode. + bool HasEnsuredCapacity() const { return true; } + +#endif + + // Returns the position in the instruction stream. + int GetPosition() { return cursor_ - contents_; } + + private: + // The limit is set to kMinimumGap bytes before the end of the data area. + // This leaves enough space for the longest possible instruction and allows + // for a single, fast space check per instruction. + static const int kMinimumGap = 32; + + byte* contents_; + byte* cursor_; + byte* limit_; + AssemblerFixup* fixup_; + bool fixups_processed_; + + // Head of linked list of slow paths + SlowPath* slow_path_; + + byte* cursor() const { return cursor_; } + byte* limit() const { return limit_; } + size_t Capacity() const { + CHECK_GE(limit_, contents_); + return (limit_ - contents_) + kMinimumGap; + } + + // Process the fixup chain starting at the given fixup. The offset is + // non-zero for fixups in the body if the preamble is non-empty. + void ProcessFixups(const MemoryRegion& region); + + // Compute the limit based on the data area and the capacity. See + // description of kMinimumGap for the reasoning behind the value. + static byte* ComputeLimit(byte* data, size_t capacity) { + return data + capacity - kMinimumGap; + } + + void ExtendCapacity(); + + friend class AssemblerFixup; +}; + +class Assembler { + public: + static Assembler* Create(InstructionSet instruction_set); + + // Emit slow paths queued during assembly + void EmitSlowPaths() { buffer_.EmitSlowPaths(this); } + + // Size of generated code + size_t CodeSize() const { return buffer_.Size(); } + + // Copy instructions out of assembly buffer into the given region of memory + void FinalizeInstructions(const MemoryRegion& region) { + buffer_.FinalizeInstructions(region); + } + + // Emit code that will create an activation on the stack + virtual void BuildFrame(size_t frame_size, ManagedRegister method_reg, + const std::vector<ManagedRegister>& callee_save_regs, + const std::vector<ManagedRegister>& entry_spills) = 0; + + // Emit code that will remove an activation from the stack + virtual void RemoveFrame(size_t frame_size, + const std::vector<ManagedRegister>& callee_save_regs) = 0; + + virtual void IncreaseFrameSize(size_t adjust) = 0; + virtual void DecreaseFrameSize(size_t adjust) = 0; + + // Store routines + virtual void Store(FrameOffset offs, ManagedRegister src, size_t size) = 0; + virtual void StoreRef(FrameOffset dest, ManagedRegister src) = 0; + virtual void StoreRawPtr(FrameOffset dest, ManagedRegister src) = 0; + + virtual void StoreImmediateToFrame(FrameOffset dest, uint32_t imm, + ManagedRegister scratch) = 0; + + virtual void StoreImmediateToThread(ThreadOffset dest, uint32_t imm, + ManagedRegister scratch) = 0; + + virtual void StoreStackOffsetToThread(ThreadOffset thr_offs, + FrameOffset fr_offs, + ManagedRegister scratch) = 0; + + virtual void StoreStackPointerToThread(ThreadOffset thr_offs) = 0; + + virtual void StoreSpanning(FrameOffset dest, ManagedRegister src, + FrameOffset in_off, ManagedRegister scratch) = 0; + + // Load routines + virtual void Load(ManagedRegister dest, FrameOffset src, size_t size) = 0; + + virtual void Load(ManagedRegister dest, ThreadOffset src, size_t size) = 0; + + virtual void LoadRef(ManagedRegister dest, FrameOffset src) = 0; + + virtual void LoadRef(ManagedRegister dest, ManagedRegister base, + MemberOffset offs) = 0; + + virtual void LoadRawPtr(ManagedRegister dest, ManagedRegister base, + Offset offs) = 0; + + virtual void LoadRawPtrFromThread(ManagedRegister dest, + ThreadOffset offs) = 0; + + // Copying routines + virtual void Move(ManagedRegister dest, ManagedRegister src, size_t size) = 0; + + virtual void CopyRawPtrFromThread(FrameOffset fr_offs, ThreadOffset thr_offs, + ManagedRegister scratch) = 0; + + virtual void CopyRawPtrToThread(ThreadOffset thr_offs, FrameOffset fr_offs, + ManagedRegister scratch) = 0; + + virtual void CopyRef(FrameOffset dest, FrameOffset src, + ManagedRegister scratch) = 0; + + virtual void Copy(FrameOffset dest, FrameOffset src, ManagedRegister scratch, size_t size) = 0; + + virtual void Copy(FrameOffset dest, ManagedRegister src_base, Offset src_offset, + ManagedRegister scratch, size_t size) = 0; + + virtual void Copy(ManagedRegister dest_base, Offset dest_offset, FrameOffset src, + ManagedRegister scratch, size_t size) = 0; + + virtual void Copy(FrameOffset dest, FrameOffset src_base, Offset src_offset, + ManagedRegister scratch, size_t size) = 0; + + virtual void Copy(ManagedRegister dest, Offset dest_offset, + ManagedRegister src, Offset src_offset, + ManagedRegister scratch, size_t size) = 0; + + virtual void Copy(FrameOffset dest, Offset dest_offset, FrameOffset src, Offset src_offset, + ManagedRegister scratch, size_t size) = 0; + + virtual void MemoryBarrier(ManagedRegister scratch) = 0; + + // Sign extension + virtual void SignExtend(ManagedRegister mreg, size_t size) = 0; + + // Zero extension + virtual void ZeroExtend(ManagedRegister mreg, size_t size) = 0; + + // Exploit fast access in managed code to Thread::Current() + virtual void GetCurrentThread(ManagedRegister tr) = 0; + virtual void GetCurrentThread(FrameOffset dest_offset, + ManagedRegister scratch) = 0; + + // Set up out_reg to hold a Object** into the SIRT, or to be NULL if the + // value is null and null_allowed. in_reg holds a possibly stale reference + // that can be used to avoid loading the SIRT entry to see if the value is + // NULL. + virtual void CreateSirtEntry(ManagedRegister out_reg, FrameOffset sirt_offset, + ManagedRegister in_reg, bool null_allowed) = 0; + + // Set up out_off to hold a Object** into the SIRT, or to be NULL if the + // value is null and null_allowed. + virtual void CreateSirtEntry(FrameOffset out_off, FrameOffset sirt_offset, + ManagedRegister scratch, bool null_allowed) = 0; + + // src holds a SIRT entry (Object**) load this into dst + virtual void LoadReferenceFromSirt(ManagedRegister dst, + ManagedRegister src) = 0; + + // Heap::VerifyObject on src. In some cases (such as a reference to this) we + // know that src may not be null. + virtual void VerifyObject(ManagedRegister src, bool could_be_null) = 0; + virtual void VerifyObject(FrameOffset src, bool could_be_null) = 0; + + // Call to address held at [base+offset] + virtual void Call(ManagedRegister base, Offset offset, + ManagedRegister scratch) = 0; + virtual void Call(FrameOffset base, Offset offset, + ManagedRegister scratch) = 0; + virtual void Call(ThreadOffset offset, ManagedRegister scratch) = 0; + + // Generate code to check if Thread::Current()->exception_ is non-null + // and branch to a ExceptionSlowPath if it is. + virtual void ExceptionPoll(ManagedRegister scratch, size_t stack_adjust) = 0; + + virtual ~Assembler() {} + + protected: + Assembler() : buffer_() {} + + AssemblerBuffer buffer_; +}; + +} // namespace art + +#endif // ART_COMPILER_UTILS_ASSEMBLER_H_ |