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// Copyright (c) 1994-2006 Sun Microsystems Inc.
// 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.
//
// - Redistribution 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 Sun Microsystems or the names of 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.
// The original source code covered by the above license above has been
// modified significantly by Google Inc.
// Copyright 2012 the V8 project authors. All rights reserved.
#ifndef V8_ASSEMBLER_H_
#define V8_ASSEMBLER_H_
#include <forward_list>
#include <iosfwd>
#include "src/allocation.h"
#include "src/deoptimize-reason.h"
#include "src/double.h"
#include "src/external-reference.h"
#include "src/globals.h"
#include "src/label.h"
#include "src/register-configuration.h"
#include "src/reglist.h"
namespace v8 {
// Forward declarations.
class ApiFunction;
namespace internal {
// Forward declarations.
class InstructionStream;
class Isolate;
class SCTableReference;
class SourcePosition;
class StatsCounter;
// -----------------------------------------------------------------------------
// Optimization for far-jmp like instructions that can be replaced by shorter.
class JumpOptimizationInfo {
public:
bool is_collecting() const { return stage_ == kCollection; }
bool is_optimizing() const { return stage_ == kOptimization; }
void set_optimizing() { stage_ = kOptimization; }
bool is_optimizable() const { return optimizable_; }
void set_optimizable() { optimizable_ = true; }
std::vector<uint32_t>& farjmp_bitmap() { return farjmp_bitmap_; }
private:
enum { kCollection, kOptimization } stage_ = kCollection;
bool optimizable_ = false;
std::vector<uint32_t> farjmp_bitmap_;
};
// -----------------------------------------------------------------------------
// Platform independent assembler base class.
enum class CodeObjectRequired { kNo, kYes };
class AssemblerBase: public Malloced {
public:
struct IsolateData {
explicit IsolateData(Isolate* isolate);
IsolateData(const IsolateData&) = default;
bool serializer_enabled_;
#if V8_TARGET_ARCH_X64
Address code_range_start_;
#endif
};
AssemblerBase(IsolateData isolate_data, void* buffer, int buffer_size);
virtual ~AssemblerBase();
IsolateData isolate_data() const { return isolate_data_; }
bool serializer_enabled() const { return isolate_data_.serializer_enabled_; }
void enable_serializer() { isolate_data_.serializer_enabled_ = true; }
bool emit_debug_code() const { return emit_debug_code_; }
void set_emit_debug_code(bool value) { emit_debug_code_ = value; }
bool predictable_code_size() const { return predictable_code_size_; }
void set_predictable_code_size(bool value) { predictable_code_size_ = value; }
uint64_t enabled_cpu_features() const { return enabled_cpu_features_; }
void set_enabled_cpu_features(uint64_t features) {
enabled_cpu_features_ = features;
}
// Features are usually enabled by CpuFeatureScope, which also asserts that
// the features are supported before they are enabled.
bool IsEnabled(CpuFeature f) {
return (enabled_cpu_features_ & (static_cast<uint64_t>(1) << f)) != 0;
}
void EnableCpuFeature(CpuFeature f) {
enabled_cpu_features_ |= (static_cast<uint64_t>(1) << f);
}
bool is_constant_pool_available() const {
if (FLAG_enable_embedded_constant_pool) {
return constant_pool_available_;
} else {
// Embedded constant pool not supported on this architecture.
UNREACHABLE();
}
}
JumpOptimizationInfo* jump_optimization_info() {
return jump_optimization_info_;
}
void set_jump_optimization_info(JumpOptimizationInfo* jump_opt) {
jump_optimization_info_ = jump_opt;
}
// Overwrite a host NaN with a quiet target NaN. Used by mksnapshot for
// cross-snapshotting.
static void QuietNaN(HeapObject* nan) { }
int pc_offset() const { return static_cast<int>(pc_ - buffer_); }
// This function is called when code generation is aborted, so that
// the assembler could clean up internal data structures.
virtual void AbortedCodeGeneration() { }
// Debugging
void Print(Isolate* isolate);
static const int kMinimalBufferSize = 4*KB;
static void FlushICache(void* start, size_t size);
protected:
// The buffer into which code and relocation info are generated. It could
// either be owned by the assembler or be provided externally.
byte* buffer_;
int buffer_size_;
bool own_buffer_;
void set_constant_pool_available(bool available) {
if (FLAG_enable_embedded_constant_pool) {
constant_pool_available_ = available;
} else {
// Embedded constant pool not supported on this architecture.
UNREACHABLE();
}
}
// The program counter, which points into the buffer above and moves forward.
byte* pc_;
private:
IsolateData isolate_data_;
uint64_t enabled_cpu_features_;
bool emit_debug_code_;
bool predictable_code_size_;
// Indicates whether the constant pool can be accessed, which is only possible
// if the pp register points to the current code object's constant pool.
bool constant_pool_available_;
JumpOptimizationInfo* jump_optimization_info_;
// Constant pool.
friend class FrameAndConstantPoolScope;
friend class ConstantPoolUnavailableScope;
};
// Avoids emitting debug code during the lifetime of this scope object.
class DontEmitDebugCodeScope BASE_EMBEDDED {
public:
explicit DontEmitDebugCodeScope(AssemblerBase* assembler)
: assembler_(assembler), old_value_(assembler->emit_debug_code()) {
assembler_->set_emit_debug_code(false);
}
~DontEmitDebugCodeScope() {
assembler_->set_emit_debug_code(old_value_);
}
private:
AssemblerBase* assembler_;
bool old_value_;
};
// Avoids using instructions that vary in size in unpredictable ways between the
// snapshot and the running VM.
class PredictableCodeSizeScope {
public:
PredictableCodeSizeScope(AssemblerBase* assembler, int expected_size);
~PredictableCodeSizeScope();
private:
AssemblerBase* const assembler_;
int const expected_size_;
int const start_offset_;
bool const old_value_;
};
// Enable a specified feature within a scope.
class CpuFeatureScope BASE_EMBEDDED {
public:
enum CheckPolicy {
kCheckSupported,
kDontCheckSupported,
};
#ifdef DEBUG
CpuFeatureScope(AssemblerBase* assembler, CpuFeature f,
CheckPolicy check = kCheckSupported);
~CpuFeatureScope();
private:
AssemblerBase* assembler_;
uint64_t old_enabled_;
#else
CpuFeatureScope(AssemblerBase* assembler, CpuFeature f,
CheckPolicy check = kCheckSupported) {}
// Define a destructor to avoid unused variable warnings.
~CpuFeatureScope() {}
#endif
};
// CpuFeatures keeps track of which features are supported by the target CPU.
// Supported features must be enabled by a CpuFeatureScope before use.
// Example:
// if (assembler->IsSupported(SSE3)) {
// CpuFeatureScope fscope(assembler, SSE3);
// // Generate code containing SSE3 instructions.
// } else {
// // Generate alternative code.
// }
class CpuFeatures : public AllStatic {
public:
static void Probe(bool cross_compile) {
STATIC_ASSERT(NUMBER_OF_CPU_FEATURES <= kBitsPerInt);
if (initialized_) return;
initialized_ = true;
ProbeImpl(cross_compile);
}
static unsigned SupportedFeatures() {
Probe(false);
return supported_;
}
static bool IsSupported(CpuFeature f) {
return (supported_ & (1u << f)) != 0;
}
static inline bool SupportsOptimizer();
static inline bool SupportsWasmSimd128();
static inline unsigned icache_line_size() {
DCHECK_NE(icache_line_size_, 0);
return icache_line_size_;
}
static inline unsigned dcache_line_size() {
DCHECK_NE(dcache_line_size_, 0);
return dcache_line_size_;
}
static void PrintTarget();
static void PrintFeatures();
private:
friend class ExternalReference;
friend class AssemblerBase;
// Flush instruction cache.
static void FlushICache(void* start, size_t size);
// Platform-dependent implementation.
static void ProbeImpl(bool cross_compile);
static unsigned supported_;
static unsigned icache_line_size_;
static unsigned dcache_line_size_;
static bool initialized_;
DISALLOW_COPY_AND_ASSIGN(CpuFeatures);
};
enum SaveFPRegsMode { kDontSaveFPRegs, kSaveFPRegs };
enum ArgvMode { kArgvOnStack, kArgvInRegister };
// Specifies whether to perform icache flush operations on RelocInfo updates.
// If FLUSH_ICACHE_IF_NEEDED, the icache will always be flushed if an
// instruction was modified. If SKIP_ICACHE_FLUSH the flush will always be
// skipped (only use this if you will flush the icache manually before it is
// executed).
enum ICacheFlushMode { FLUSH_ICACHE_IF_NEEDED, SKIP_ICACHE_FLUSH };
// -----------------------------------------------------------------------------
// Relocation information
// Relocation information consists of the address (pc) of the datum
// to which the relocation information applies, the relocation mode
// (rmode), and an optional data field. The relocation mode may be
// "descriptive" and not indicate a need for relocation, but simply
// describe a property of the datum. Such rmodes are useful for GC
// and nice disassembly output.
class RelocInfo {
public:
enum Flag : uint8_t {
kNoFlags = 0,
kInNativeWasmCode = 1u << 0, // Reloc info belongs to native wasm code.
};
typedef base::Flags<Flag> Flags;
// This string is used to add padding comments to the reloc info in cases
// where we are not sure to have enough space for patching in during
// lazy deoptimization. This is the case if we have indirect calls for which
// we do not normally record relocation info.
static const char* const kFillerCommentString;
// The minimum size of a comment is equal to two bytes for the extra tagged
// pc and kPointerSize for the actual pointer to the comment.
static const int kMinRelocCommentSize = 2 + kPointerSize;
// The maximum size for a call instruction including pc-jump.
static const int kMaxCallSize = 6;
// The maximum pc delta that will use the short encoding.
static const int kMaxSmallPCDelta;
enum Mode : int8_t {
// Please note the order is important (see IsCodeTarget, IsGCRelocMode).
CODE_TARGET,
EMBEDDED_OBJECT,
// Wasm entries are to relocate pointers into the wasm memory embedded in
// wasm code. Everything after WASM_CONTEXT_REFERENCE (inclusive) is not
// GC'ed.
WASM_CONTEXT_REFERENCE,
WASM_FUNCTION_TABLE_SIZE_REFERENCE,
WASM_GLOBAL_HANDLE,
WASM_CALL,
JS_TO_WASM_CALL,
RUNTIME_ENTRY,
COMMENT,
EXTERNAL_REFERENCE, // The address of an external C++ function.
INTERNAL_REFERENCE, // An address inside the same function.
// Encoded internal reference, used only on MIPS, MIPS64 and PPC.
INTERNAL_REFERENCE_ENCODED,
// Marks constant and veneer pools. Only used on ARM and ARM64.
// They use a custom noncompact encoding.
CONST_POOL,
VENEER_POOL,
DEOPT_SCRIPT_OFFSET,
DEOPT_INLINING_ID, // Deoptimization source position.
DEOPT_REASON, // Deoptimization reason index.
DEOPT_ID, // Deoptimization inlining id.
// This is not an actual reloc mode, but used to encode a long pc jump that
// cannot be encoded as part of another record.
PC_JUMP,
// Pseudo-types
NUMBER_OF_MODES,
NONE, // never recorded value
FIRST_REAL_RELOC_MODE = CODE_TARGET,
LAST_REAL_RELOC_MODE = VENEER_POOL,
LAST_CODE_ENUM = CODE_TARGET,
LAST_GCED_ENUM = EMBEDDED_OBJECT,
FIRST_SHAREABLE_RELOC_MODE = RUNTIME_ENTRY,
};
STATIC_ASSERT(NUMBER_OF_MODES <= kBitsPerInt);
RelocInfo() = default;
RelocInfo(byte* pc, Mode rmode, intptr_t data, Code* host)
: pc_(pc), rmode_(rmode), data_(data), host_(host) {}
static inline bool IsRealRelocMode(Mode mode) {
return mode >= FIRST_REAL_RELOC_MODE && mode <= LAST_REAL_RELOC_MODE;
}
static inline bool IsCodeTarget(Mode mode) {
return mode <= LAST_CODE_ENUM;
}
static inline bool IsEmbeddedObject(Mode mode) {
return mode == EMBEDDED_OBJECT;
}
static inline bool IsRuntimeEntry(Mode mode) {
return mode == RUNTIME_ENTRY;
}
static inline bool IsWasmCall(Mode mode) { return mode == WASM_CALL; }
// Is the relocation mode affected by GC?
static inline bool IsGCRelocMode(Mode mode) {
return mode <= LAST_GCED_ENUM;
}
static inline bool IsComment(Mode mode) {
return mode == COMMENT;
}
static inline bool IsConstPool(Mode mode) {
return mode == CONST_POOL;
}
static inline bool IsVeneerPool(Mode mode) {
return mode == VENEER_POOL;
}
static inline bool IsDeoptPosition(Mode mode) {
return mode == DEOPT_SCRIPT_OFFSET || mode == DEOPT_INLINING_ID;
}
static inline bool IsDeoptReason(Mode mode) {
return mode == DEOPT_REASON;
}
static inline bool IsDeoptId(Mode mode) {
return mode == DEOPT_ID;
}
static inline bool IsExternalReference(Mode mode) {
return mode == EXTERNAL_REFERENCE;
}
static inline bool IsInternalReference(Mode mode) {
return mode == INTERNAL_REFERENCE;
}
static inline bool IsInternalReferenceEncoded(Mode mode) {
return mode == INTERNAL_REFERENCE_ENCODED;
}
static inline bool IsNone(Mode mode) { return mode == NONE; }
static inline bool IsWasmContextReference(Mode mode) {
return mode == WASM_CONTEXT_REFERENCE;
}
static inline bool IsWasmFunctionTableSizeReference(Mode mode) {
return mode == WASM_FUNCTION_TABLE_SIZE_REFERENCE;
}
static inline bool IsWasmReference(Mode mode) {
return IsWasmPtrReference(mode) || IsWasmSizeReference(mode);
}
static inline bool IsWasmSizeReference(Mode mode) {
return IsWasmFunctionTableSizeReference(mode);
}
static inline bool IsWasmPtrReference(Mode mode) {
return mode == WASM_CONTEXT_REFERENCE || mode == WASM_GLOBAL_HANDLE ||
mode == WASM_CALL || mode == JS_TO_WASM_CALL;
}
static constexpr int ModeMask(Mode mode) { return 1 << mode; }
// Accessors
byte* pc() const { return pc_; }
void set_pc(byte* pc) { pc_ = pc; }
Mode rmode() const { return rmode_; }
intptr_t data() const { return data_; }
Code* host() const { return host_; }
Address constant_pool() const { return constant_pool_; }
void set_constant_pool(Address constant_pool) {
constant_pool_ = constant_pool;
}
// Apply a relocation by delta bytes. When the code object is moved, PC
// relative addresses have to be updated as well as absolute addresses
// inside the code (internal references).
// Do not forget to flush the icache afterwards!
INLINE(void apply(intptr_t delta));
// Is the pointer this relocation info refers to coded like a plain pointer
// or is it strange in some way (e.g. relative or patched into a series of
// instructions).
bool IsCodedSpecially();
// If true, the pointer this relocation info refers to is an entry in the
// constant pool, otherwise the pointer is embedded in the instruction stream.
bool IsInConstantPool();
Address wasm_context_reference() const;
uint32_t wasm_function_table_size_reference() const;
Address global_handle() const;
Address js_to_wasm_address() const;
Address wasm_call_address() const;
void set_wasm_context_reference(
Address address,
ICacheFlushMode icache_flush_mode = FLUSH_ICACHE_IF_NEEDED);
void update_wasm_function_table_size_reference(
uint32_t old_base, uint32_t new_base,
ICacheFlushMode icache_flush_mode = FLUSH_ICACHE_IF_NEEDED);
void set_target_address(
Address target,
WriteBarrierMode write_barrier_mode = UPDATE_WRITE_BARRIER,
ICacheFlushMode icache_flush_mode = FLUSH_ICACHE_IF_NEEDED);
void set_global_handle(Address address, ICacheFlushMode icache_flush_mode =
FLUSH_ICACHE_IF_NEEDED);
void set_wasm_call_address(
Address, ICacheFlushMode icache_flush_mode = FLUSH_ICACHE_IF_NEEDED);
void set_js_to_wasm_address(
Address, ICacheFlushMode icache_flush_mode = FLUSH_ICACHE_IF_NEEDED);
// this relocation applies to;
// can only be called if IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_)
INLINE(Address target_address());
INLINE(HeapObject* target_object());
INLINE(Handle<HeapObject> target_object_handle(Assembler* origin));
INLINE(void set_target_object(
HeapObject* target,
WriteBarrierMode write_barrier_mode = UPDATE_WRITE_BARRIER,
ICacheFlushMode icache_flush_mode = FLUSH_ICACHE_IF_NEEDED));
INLINE(Address target_runtime_entry(Assembler* origin));
INLINE(void set_target_runtime_entry(
Address target,
WriteBarrierMode write_barrier_mode = UPDATE_WRITE_BARRIER,
ICacheFlushMode icache_flush_mode = FLUSH_ICACHE_IF_NEEDED));
INLINE(Cell* target_cell());
INLINE(Handle<Cell> target_cell_handle());
INLINE(void set_target_cell(
Cell* cell, WriteBarrierMode write_barrier_mode = UPDATE_WRITE_BARRIER,
ICacheFlushMode icache_flush_mode = FLUSH_ICACHE_IF_NEEDED));
// Returns the address of the constant pool entry where the target address
// is held. This should only be called if IsInConstantPool returns true.
INLINE(Address constant_pool_entry_address());
// Read the address of the word containing the target_address in an
// instruction stream. What this means exactly is architecture-independent.
// The only architecture-independent user of this function is the serializer.
// The serializer uses it to find out how many raw bytes of instruction to
// output before the next target. Architecture-independent code shouldn't
// dereference the pointer it gets back from this.
INLINE(Address target_address_address());
// This indicates how much space a target takes up when deserializing a code
// stream. For most architectures this is just the size of a pointer. For
// an instruction like movw/movt where the target bits are mixed into the
// instruction bits the size of the target will be zero, indicating that the
// serializer should not step forwards in memory after a target is resolved
// and written. In this case the target_address_address function above
// should return the end of the instructions to be patched, allowing the
// deserializer to deserialize the instructions as raw bytes and put them in
// place, ready to be patched with the target.
INLINE(int target_address_size());
// Read the reference in the instruction this relocation
// applies to; can only be called if rmode_ is EXTERNAL_REFERENCE.
INLINE(Address target_external_reference());
// Read the reference in the instruction this relocation
// applies to; can only be called if rmode_ is INTERNAL_REFERENCE.
INLINE(Address target_internal_reference());
// Return the reference address this relocation applies to;
// can only be called if rmode_ is INTERNAL_REFERENCE.
INLINE(Address target_internal_reference_address());
// Wipe out a relocation to a fixed value, used for making snapshots
// reproducible.
INLINE(void WipeOut());
template <typename ObjectVisitor>
inline void Visit(ObjectVisitor* v);
#ifdef DEBUG
// Check whether the given code contains relocation information that
// either is position-relative or movable by the garbage collector.
static bool RequiresRelocation(const CodeDesc& desc);
#endif
#ifdef ENABLE_DISASSEMBLER
// Printing
static const char* RelocModeName(Mode rmode);
void Print(Isolate* isolate, std::ostream& os); // NOLINT
#endif // ENABLE_DISASSEMBLER
#ifdef VERIFY_HEAP
void Verify(Isolate* isolate);
#endif
static const int kCodeTargetMask = (1 << (LAST_CODE_ENUM + 1)) - 1;
static const int kApplyMask; // Modes affected by apply. Depends on arch.
private:
void set_embedded_address(Address address, ICacheFlushMode flush_mode);
void set_embedded_size(uint32_t size, ICacheFlushMode flush_mode);
uint32_t embedded_size() const;
Address embedded_address() const;
// On ARM, note that pc_ is the address of the constant pool entry
// to be relocated and not the address of the instruction
// referencing the constant pool entry (except when rmode_ ==
// comment).
byte* pc_;
Mode rmode_;
intptr_t data_ = 0;
Code* host_;
Address constant_pool_ = nullptr;
Flags flags_;
friend class RelocIterator;
};
// RelocInfoWriter serializes a stream of relocation info. It writes towards
// lower addresses.
class RelocInfoWriter BASE_EMBEDDED {
public:
RelocInfoWriter() : pos_(nullptr), last_pc_(nullptr) {}
byte* pos() const { return pos_; }
byte* last_pc() const { return last_pc_; }
void Write(const RelocInfo* rinfo);
// Update the state of the stream after reloc info buffer
// and/or code is moved while the stream is active.
void Reposition(byte* pos, byte* pc) {
pos_ = pos;
last_pc_ = pc;
}
// Max size (bytes) of a written RelocInfo. Longest encoding is
// ExtraTag, VariableLengthPCJump, ExtraTag, pc_delta, data_delta.
static constexpr int kMaxSize = 1 + 4 + 1 + 1 + kPointerSize;
private:
inline uint32_t WriteLongPCJump(uint32_t pc_delta);
inline void WriteShortTaggedPC(uint32_t pc_delta, int tag);
inline void WriteShortData(intptr_t data_delta);
inline void WriteMode(RelocInfo::Mode rmode);
inline void WriteModeAndPC(uint32_t pc_delta, RelocInfo::Mode rmode);
inline void WriteIntData(int data_delta);
inline void WriteData(intptr_t data_delta);
byte* pos_;
byte* last_pc_;
DISALLOW_COPY_AND_ASSIGN(RelocInfoWriter);
};
// A RelocIterator iterates over relocation information.
// Typical use:
//
// for (RelocIterator it(code); !it.done(); it.next()) {
// // do something with it.rinfo() here
// }
//
// A mask can be specified to skip unwanted modes.
class RelocIterator: public Malloced {
public:
// Create a new iterator positioned at
// the beginning of the reloc info.
// Relocation information with mode k is included in the
// iteration iff bit k of mode_mask is set.
explicit RelocIterator(Code* code, int mode_mask = -1);
explicit RelocIterator(const CodeDesc& desc, int mode_mask = -1);
explicit RelocIterator(Vector<byte> instructions,
Vector<const byte> reloc_info, Address const_pool,
int mode_mask = -1);
RelocIterator(RelocIterator&&) = default;
RelocIterator& operator=(RelocIterator&&) = default;
// Iteration
bool done() const { return done_; }
void next();
// Return pointer valid until next next().
RelocInfo* rinfo() {
DCHECK(!done());
return &rinfo_;
}
private:
// Advance* moves the position before/after reading.
// *Read* reads from current byte(s) into rinfo_.
// *Get* just reads and returns info on current byte.
void Advance(int bytes = 1) { pos_ -= bytes; }
int AdvanceGetTag();
RelocInfo::Mode GetMode();
void AdvanceReadLongPCJump();
void ReadShortTaggedPC();
void ReadShortData();
void AdvanceReadPC();
void AdvanceReadInt();
void AdvanceReadData();
// If the given mode is wanted, set it in rinfo_ and return true.
// Else return false. Used for efficiently skipping unwanted modes.
bool SetMode(RelocInfo::Mode mode) {
return (mode_mask_ & (1 << mode)) ? (rinfo_.rmode_ = mode, true) : false;
}
const byte* pos_;
const byte* end_;
RelocInfo rinfo_;
bool done_ = false;
const int mode_mask_;
DISALLOW_COPY_AND_ASSIGN(RelocIterator);
};
// -----------------------------------------------------------------------------
// Utility functions
// Computes pow(x, y) with the special cases in the spec for Math.pow.
double power_helper(Isolate* isolate, double x, double y);
double power_double_int(double x, int y);
double power_double_double(double x, double y);
// -----------------------------------------------------------------------------
// Constant pool support
class ConstantPoolEntry {
public:
ConstantPoolEntry() {}
ConstantPoolEntry(int position, intptr_t value, bool sharing_ok,
RelocInfo::Mode rmode = RelocInfo::NONE)
: position_(position),
merged_index_(sharing_ok ? SHARING_ALLOWED : SHARING_PROHIBITED),
value_(value),
rmode_(rmode) {}
ConstantPoolEntry(int position, Double value,
RelocInfo::Mode rmode = RelocInfo::NONE)
: position_(position),
merged_index_(SHARING_ALLOWED),
value64_(value.AsUint64()),
rmode_(rmode) {}
int position() const { return position_; }
bool sharing_ok() const { return merged_index_ != SHARING_PROHIBITED; }
bool is_merged() const { return merged_index_ >= 0; }
int merged_index(void) const {
DCHECK(is_merged());
return merged_index_;
}
void set_merged_index(int index) {
DCHECK(sharing_ok());
merged_index_ = index;
DCHECK(is_merged());
}
int offset(void) const {
DCHECK_GE(merged_index_, 0);
return merged_index_;
}
void set_offset(int offset) {
DCHECK_GE(offset, 0);
merged_index_ = offset;
}
intptr_t value() const { return value_; }
uint64_t value64() const { return value64_; }
RelocInfo::Mode rmode() const { return rmode_; }
enum Type { INTPTR, DOUBLE, NUMBER_OF_TYPES };
static int size(Type type) {
return (type == INTPTR) ? kPointerSize : kDoubleSize;
}
enum Access { REGULAR, OVERFLOWED };
private:
int position_;
int merged_index_;
union {
intptr_t value_;
uint64_t value64_;
};
// TODO(leszeks): The way we use this, it could probably be packed into
// merged_index_ if size is a concern.
RelocInfo::Mode rmode_;
enum { SHARING_PROHIBITED = -2, SHARING_ALLOWED = -1 };
};
// -----------------------------------------------------------------------------
// Embedded constant pool support
class ConstantPoolBuilder BASE_EMBEDDED {
public:
ConstantPoolBuilder(int ptr_reach_bits, int double_reach_bits);
// Add pointer-sized constant to the embedded constant pool
ConstantPoolEntry::Access AddEntry(int position, intptr_t value,
bool sharing_ok) {
ConstantPoolEntry entry(position, value, sharing_ok);
return AddEntry(entry, ConstantPoolEntry::INTPTR);
}
// Add double constant to the embedded constant pool
ConstantPoolEntry::Access AddEntry(int position, Double value) {
ConstantPoolEntry entry(position, value);
return AddEntry(entry, ConstantPoolEntry::DOUBLE);
}
// Add double constant to the embedded constant pool
ConstantPoolEntry::Access AddEntry(int position, double value) {
return AddEntry(position, Double(value));
}
// Previews the access type required for the next new entry to be added.
ConstantPoolEntry::Access NextAccess(ConstantPoolEntry::Type type) const;
bool IsEmpty() {
return info_[ConstantPoolEntry::INTPTR].entries.empty() &&
info_[ConstantPoolEntry::INTPTR].shared_entries.empty() &&
info_[ConstantPoolEntry::DOUBLE].entries.empty() &&
info_[ConstantPoolEntry::DOUBLE].shared_entries.empty();
}
// Emit the constant pool. Invoke only after all entries have been
// added and all instructions have been emitted.
// Returns position of the emitted pool (zero implies no constant pool).
int Emit(Assembler* assm);
// Returns the label associated with the start of the constant pool.
// Linking to this label in the function prologue may provide an
// efficient means of constant pool pointer register initialization
// on some architectures.
inline Label* EmittedPosition() { return &emitted_label_; }
private:
ConstantPoolEntry::Access AddEntry(ConstantPoolEntry& entry,
ConstantPoolEntry::Type type);
void EmitSharedEntries(Assembler* assm, ConstantPoolEntry::Type type);
void EmitGroup(Assembler* assm, ConstantPoolEntry::Access access,
ConstantPoolEntry::Type type);
struct PerTypeEntryInfo {
PerTypeEntryInfo() : regular_count(0), overflow_start(-1) {}
bool overflow() const {
return (overflow_start >= 0 &&
overflow_start < static_cast<int>(entries.size()));
}
int regular_reach_bits;
int regular_count;
int overflow_start;
std::vector<ConstantPoolEntry> entries;
std::vector<ConstantPoolEntry> shared_entries;
};
Label emitted_label_; // Records pc_offset of emitted pool
PerTypeEntryInfo info_[ConstantPoolEntry::NUMBER_OF_TYPES];
};
class HeapObjectRequest {
public:
explicit HeapObjectRequest(double heap_number, int offset = -1);
explicit HeapObjectRequest(CodeStub* code_stub, int offset = -1);
enum Kind { kHeapNumber, kCodeStub };
Kind kind() const { return kind_; }
double heap_number() const {
DCHECK_EQ(kind(), kHeapNumber);
return value_.heap_number;
}
CodeStub* code_stub() const {
DCHECK_EQ(kind(), kCodeStub);
return value_.code_stub;
}
// The code buffer offset at the time of the request.
int offset() const {
DCHECK_GE(offset_, 0);
return offset_;
}
void set_offset(int offset) {
DCHECK_LT(offset_, 0);
offset_ = offset;
DCHECK_GE(offset_, 0);
}
private:
Kind kind_;
union {
double heap_number;
CodeStub* code_stub;
} value_;
int offset_;
};
// Base type for CPU Registers.
//
// 1) We would prefer to use an enum for registers, but enum values are
// assignment-compatible with int, which has caused code-generation bugs.
//
// 2) By not using an enum, we are possibly preventing the compiler from
// doing certain constant folds, which may significantly reduce the
// code generated for some assembly instructions (because they boil down
// to a few constants). If this is a problem, we could change the code
// such that we use an enum in optimized mode, and the class in debug
// mode. This way we get the compile-time error checking in debug mode
// and best performance in optimized code.
template <typename SubType, int kAfterLastRegister>
class RegisterBase {
// Internal enum class; used for calling constexpr methods, where we need to
// pass an integral type as template parameter.
enum class RegisterCode : int { kFirst = 0, kAfterLast = kAfterLastRegister };
public:
static constexpr int kCode_no_reg = -1;
static constexpr int kNumRegisters = kAfterLastRegister;
static constexpr SubType no_reg() { return SubType{kCode_no_reg}; }
template <int code>
static constexpr SubType from_code() {
static_assert(code >= 0 && code < kNumRegisters, "must be valid reg code");
return SubType{code};
}
constexpr operator RegisterCode() const {
return static_cast<RegisterCode>(reg_code_);
}
template <RegisterCode reg_code>
static constexpr int code() {
static_assert(
reg_code >= RegisterCode::kFirst && reg_code < RegisterCode::kAfterLast,
"must be valid reg");
return static_cast<int>(reg_code);
}
template <RegisterCode reg_code>
static constexpr int bit() {
return 1 << code<reg_code>();
}
static SubType from_code(int code) {
DCHECK_LE(0, code);
DCHECK_GT(kNumRegisters, code);
return SubType{code};
}
template <RegisterCode... reg_codes>
static constexpr RegList ListOf() {
return CombineRegLists(RegisterBase::bit<reg_codes>()...);
}
bool is_valid() const { return reg_code_ != kCode_no_reg; }
int code() const {
DCHECK(is_valid());
return reg_code_;
}
int bit() const { return 1 << code(); }
inline constexpr bool operator==(SubType other) const {
return reg_code_ == other.reg_code_;
}
inline constexpr bool operator!=(SubType other) const {
return reg_code_ != other.reg_code_;
}
protected:
explicit constexpr RegisterBase(int code) : reg_code_(code) {}
int reg_code_;
};
template <typename SubType, int kAfterLastRegister>
inline std::ostream& operator<<(std::ostream& os,
RegisterBase<SubType, kAfterLastRegister> reg) {
return reg.is_valid() ? os << "r" << reg.code() : os << "<invalid reg>";
}
} // namespace internal
} // namespace v8
#endif // V8_ASSEMBLER_H_