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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 2006-2009 the V8 project authors. All rights reserved.
#ifndef V8_ASSEMBLER_H_
#define V8_ASSEMBLER_H_
#include "runtime.h"
#include "top.h"
#include "token.h"
#include "objects.h"
namespace v8 {
namespace internal {
// -----------------------------------------------------------------------------
// Labels represent pc locations; they are typically jump or call targets.
// After declaration, a label can be freely used to denote known or (yet)
// unknown pc location. Assembler::bind() is used to bind a label to the
// current pc. A label can be bound only once.
class Label BASE_EMBEDDED {
public:
INLINE(Label()) { Unuse(); }
INLINE(~Label()) { ASSERT(!is_linked()); }
INLINE(void Unuse()) { pos_ = 0; }
INLINE(bool is_bound() const) { return pos_ < 0; }
INLINE(bool is_unused() const) { return pos_ == 0; }
INLINE(bool is_linked() const) { return pos_ > 0; }
// Returns the position of bound or linked labels. Cannot be used
// for unused labels.
int pos() const;
private:
// pos_ encodes both the binding state (via its sign)
// and the binding position (via its value) of a label.
//
// pos_ < 0 bound label, pos() returns the jump target position
// pos_ == 0 unused label
// pos_ > 0 linked label, pos() returns the last reference position
int pos_;
void bind_to(int pos) {
pos_ = -pos - 1;
ASSERT(is_bound());
}
void link_to(int pos) {
pos_ = pos + 1;
ASSERT(is_linked());
}
friend class Assembler;
friend class RegexpAssembler;
friend class Displacement;
friend class ShadowTarget;
friend class RegExpMacroAssemblerIrregexp;
};
// -----------------------------------------------------------------------------
// NearLabels are labels used for short jumps (in Intel jargon).
// NearLabels should be used if it can be guaranteed that the jump range is
// within -128 to +127. We already use short jumps when jumping backwards,
// so using a NearLabel will only have performance impact if used for forward
// jumps.
class NearLabel BASE_EMBEDDED {
public:
NearLabel() { Unuse(); }
~NearLabel() { ASSERT(!is_linked()); }
void Unuse() {
pos_ = -1;
unresolved_branches_ = 0;
#ifdef DEBUG
for (int i = 0; i < kMaxUnresolvedBranches; i++) {
unresolved_positions_[i] = -1;
}
#endif
}
int pos() {
ASSERT(is_bound());
return pos_;
}
bool is_bound() { return pos_ >= 0; }
bool is_linked() { return !is_bound() && unresolved_branches_ > 0; }
bool is_unused() { return !is_bound() && unresolved_branches_ == 0; }
void bind_to(int position) {
ASSERT(!is_bound());
pos_ = position;
}
void link_to(int position) {
ASSERT(!is_bound());
ASSERT(unresolved_branches_ < kMaxUnresolvedBranches);
unresolved_positions_[unresolved_branches_++] = position;
}
private:
static const int kMaxUnresolvedBranches = 8;
int pos_;
int unresolved_branches_;
int unresolved_positions_[kMaxUnresolvedBranches];
friend class Assembler;
};
// -----------------------------------------------------------------------------
// 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 BASE_EMBEDDED {
public:
// The constant kNoPosition is used with the collecting of source positions
// in the relocation information. Two types of source positions are collected
// "position" (RelocMode position) and "statement position" (RelocMode
// statement_position). The "position" is collected at places in the source
// code which are of interest when making stack traces to pin-point the source
// location of a stack frame as close as possible. The "statement position" is
// collected at the beginning at each statement, and is used to indicate
// possible break locations. kNoPosition is used to indicate an
// invalid/uninitialized position value.
static const int kNoPosition = -1;
enum Mode {
// Please note the order is important (see IsCodeTarget, IsGCRelocMode).
CONSTRUCT_CALL, // code target that is a call to a JavaScript constructor.
CODE_TARGET_CONTEXT, // Code target used for contextual loads.
DEBUG_BREAK, // Code target for the debugger statement.
CODE_TARGET, // Code target which is not any of the above.
EMBEDDED_OBJECT,
// Everything after runtime_entry (inclusive) is not GC'ed.
RUNTIME_ENTRY,
JS_RETURN, // Marks start of the ExitJSFrame code.
COMMENT,
POSITION, // See comment for kNoPosition above.
STATEMENT_POSITION, // See comment for kNoPosition above.
DEBUG_BREAK_SLOT, // Additional code inserted for debug break slot.
EXTERNAL_REFERENCE, // The address of an external C++ function.
INTERNAL_REFERENCE, // An address inside the same function.
// add more as needed
// Pseudo-types
NUMBER_OF_MODES, // must be no greater than 14 - see RelocInfoWriter
NONE, // never recorded
LAST_CODE_ENUM = CODE_TARGET,
LAST_GCED_ENUM = EMBEDDED_OBJECT
};
RelocInfo() {}
RelocInfo(byte* pc, Mode rmode, intptr_t data)
: pc_(pc), rmode_(rmode), data_(data) {
}
static inline bool IsConstructCall(Mode mode) {
return mode == CONSTRUCT_CALL;
}
static inline bool IsCodeTarget(Mode mode) {
return mode <= LAST_CODE_ENUM;
}
// Is the relocation mode affected by GC?
static inline bool IsGCRelocMode(Mode mode) {
return mode <= LAST_GCED_ENUM;
}
static inline bool IsJSReturn(Mode mode) {
return mode == JS_RETURN;
}
static inline bool IsComment(Mode mode) {
return mode == COMMENT;
}
static inline bool IsPosition(Mode mode) {
return mode == POSITION || mode == STATEMENT_POSITION;
}
static inline bool IsStatementPosition(Mode mode) {
return mode == STATEMENT_POSITION;
}
static inline bool IsExternalReference(Mode mode) {
return mode == EXTERNAL_REFERENCE;
}
static inline bool IsInternalReference(Mode mode) {
return mode == INTERNAL_REFERENCE;
}
static inline bool IsDebugBreakSlot(Mode mode) {
return mode == DEBUG_BREAK_SLOT;
}
static inline 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_; }
// Apply a relocation by delta bytes
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 (eg relative or patched into a series of
// instructions).
bool IsCodedSpecially();
// Read/modify the code target in the branch/call instruction
// this relocation applies to;
// can only be called if IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY
INLINE(Address target_address());
INLINE(void set_target_address(Address target));
INLINE(Object* target_object());
INLINE(Handle<Object> target_object_handle(Assembler* origin));
INLINE(Object** target_object_address());
INLINE(void set_target_object(Object* target));
// 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/modify the reference in the instruction this relocation
// applies to; can only be called if rmode_ is external_reference
INLINE(Address* target_reference_address());
// Read/modify the address of a call instruction. This is used to relocate
// the break points where straight-line code is patched with a call
// instruction.
INLINE(Address call_address());
INLINE(void set_call_address(Address target));
INLINE(Object* call_object());
INLINE(void set_call_object(Object* target));
INLINE(Object** call_object_address());
template<typename StaticVisitor> inline void Visit();
inline void Visit(ObjectVisitor* v);
// Patch the code with some other code.
void PatchCode(byte* instructions, int instruction_count);
// Patch the code with a call.
void PatchCodeWithCall(Address target, int guard_bytes);
// Check whether this return sequence has been patched
// with a call to the debugger.
INLINE(bool IsPatchedReturnSequence());
// Check whether this debug break slot has been patched with a call to the
// debugger.
INLINE(bool IsPatchedDebugBreakSlotSequence());
#ifdef ENABLE_DISASSEMBLER
// Printing
static const char* RelocModeName(Mode rmode);
void Print();
#endif // ENABLE_DISASSEMBLER
#ifdef DEBUG
// Debugging
void Verify();
#endif
static const int kCodeTargetMask = (1 << (LAST_CODE_ENUM + 1)) - 1;
static const int kPositionMask = 1 << POSITION | 1 << STATEMENT_POSITION;
static const int kDebugMask = kPositionMask | 1 << COMMENT;
static const int kApplyMask; // Modes affected by apply. Depends on arch.
private:
// 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_;
friend class RelocIterator;
};
// RelocInfoWriter serializes a stream of relocation info. It writes towards
// lower addresses.
class RelocInfoWriter BASE_EMBEDDED {
public:
RelocInfoWriter() : pos_(NULL), last_pc_(NULL), last_data_(0) {}
RelocInfoWriter(byte* pos, byte* pc) : pos_(pos), last_pc_(pc),
last_data_(0) {}
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, ExtraTag, data_delta.
// On ia32 and arm this is 1 + 4 + 1 + 1 + 1 + 4 = 12.
// On x64 this is 1 + 4 + 1 + 1 + 1 + 8 == 16;
// Here we use the maximum of the two.
static const int kMaxSize = 16;
private:
inline uint32_t WriteVariableLengthPCJump(uint32_t pc_delta);
inline void WriteTaggedPC(uint32_t pc_delta, int tag);
inline void WriteExtraTaggedPC(uint32_t pc_delta, int extra_tag);
inline void WriteExtraTaggedData(intptr_t data_delta, int top_tag);
inline void WriteTaggedData(intptr_t data_delta, int tag);
inline void WriteExtraTag(int extra_tag, int top_tag);
byte* pos_;
byte* last_pc_;
intptr_t last_data_;
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);
// Iteration
bool done() const { return done_; }
void next();
// Return pointer valid until next next().
RelocInfo* rinfo() {
ASSERT(!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();
int GetExtraTag();
int GetTopTag();
void ReadTaggedPC();
void AdvanceReadPC();
void AdvanceReadData();
void AdvanceReadVariableLengthPCJump();
int GetPositionTypeTag();
void ReadTaggedData();
static RelocInfo::Mode DebugInfoModeFromTag(int tag);
// 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;
}
byte* pos_;
byte* end_;
RelocInfo rinfo_;
bool done_;
int mode_mask_;
DISALLOW_COPY_AND_ASSIGN(RelocIterator);
};
//------------------------------------------------------------------------------
// External function
//----------------------------------------------------------------------------
class IC_Utility;
class SCTableReference;
#ifdef ENABLE_DEBUGGER_SUPPORT
class Debug_Address;
#endif
typedef void* ExternalReferenceRedirector(void* original, bool fp_return);
// An ExternalReference represents a C++ address used in the generated
// code. All references to C++ functions and variables must be encapsulated in
// an ExternalReference instance. This is done in order to track the origin of
// all external references in the code so that they can be bound to the correct
// addresses when deserializing a heap.
class ExternalReference BASE_EMBEDDED {
public:
explicit ExternalReference(Builtins::CFunctionId id);
explicit ExternalReference(ApiFunction* ptr);
explicit ExternalReference(Builtins::Name name);
explicit ExternalReference(Runtime::FunctionId id);
explicit ExternalReference(Runtime::Function* f);
explicit ExternalReference(const IC_Utility& ic_utility);
#ifdef ENABLE_DEBUGGER_SUPPORT
explicit ExternalReference(const Debug_Address& debug_address);
#endif
explicit ExternalReference(StatsCounter* counter);
explicit ExternalReference(Top::AddressId id);
explicit ExternalReference(const SCTableReference& table_ref);
// One-of-a-kind references. These references are not part of a general
// pattern. This means that they have to be added to the
// ExternalReferenceTable in serialize.cc manually.
static ExternalReference perform_gc_function();
static ExternalReference fill_heap_number_with_random_function();
static ExternalReference random_uint32_function();
static ExternalReference transcendental_cache_array_address();
static ExternalReference delete_handle_scope_extensions();
// Static data in the keyed lookup cache.
static ExternalReference keyed_lookup_cache_keys();
static ExternalReference keyed_lookup_cache_field_offsets();
// Static variable Factory::the_hole_value.location()
static ExternalReference the_hole_value_location();
// Static variable Heap::roots_address()
static ExternalReference roots_address();
// Static variable StackGuard::address_of_jslimit()
static ExternalReference address_of_stack_limit();
// Static variable StackGuard::address_of_real_jslimit()
static ExternalReference address_of_real_stack_limit();
// Static variable RegExpStack::limit_address()
static ExternalReference address_of_regexp_stack_limit();
// Static variables for RegExp.
static ExternalReference address_of_static_offsets_vector();
static ExternalReference address_of_regexp_stack_memory_address();
static ExternalReference address_of_regexp_stack_memory_size();
// Static variable Heap::NewSpaceStart()
static ExternalReference new_space_start();
static ExternalReference new_space_mask();
static ExternalReference heap_always_allocate_scope_depth();
// Used for fast allocation in generated code.
static ExternalReference new_space_allocation_top_address();
static ExternalReference new_space_allocation_limit_address();
static ExternalReference double_fp_operation(Token::Value operation);
static ExternalReference compare_doubles();
static ExternalReference handle_scope_next_address();
static ExternalReference handle_scope_limit_address();
static ExternalReference handle_scope_level_address();
static ExternalReference scheduled_exception_address();
Address address() const {return reinterpret_cast<Address>(address_);}
#ifdef ENABLE_DEBUGGER_SUPPORT
// Function Debug::Break()
static ExternalReference debug_break();
// Used to check if single stepping is enabled in generated code.
static ExternalReference debug_step_in_fp_address();
#endif
#ifndef V8_INTERPRETED_REGEXP
// C functions called from RegExp generated code.
// Function NativeRegExpMacroAssembler::CaseInsensitiveCompareUC16()
static ExternalReference re_case_insensitive_compare_uc16();
// Function RegExpMacroAssembler*::CheckStackGuardState()
static ExternalReference re_check_stack_guard_state();
// Function NativeRegExpMacroAssembler::GrowStack()
static ExternalReference re_grow_stack();
// byte NativeRegExpMacroAssembler::word_character_bitmap
static ExternalReference re_word_character_map();
#endif
// This lets you register a function that rewrites all external references.
// Used by the ARM simulator to catch calls to external references.
static void set_redirector(ExternalReferenceRedirector* redirector) {
ASSERT(redirector_ == NULL); // We can't stack them.
redirector_ = redirector;
}
private:
explicit ExternalReference(void* address)
: address_(address) {}
static ExternalReferenceRedirector* redirector_;
static void* Redirect(void* address, bool fp_return = false) {
if (redirector_ == NULL) return address;
void* answer = (*redirector_)(address, fp_return);
return answer;
}
static void* Redirect(Address address_arg, bool fp_return = false) {
void* address = reinterpret_cast<void*>(address_arg);
void* answer = (redirector_ == NULL) ?
address :
(*redirector_)(address, fp_return);
return answer;
}
void* address_;
};
// -----------------------------------------------------------------------------
// Position recording support
enum PositionRecordingType { FORCED_POSITION, NORMAL_POSITION };
class PositionsRecorder BASE_EMBEDDED {
public:
explicit PositionsRecorder(Assembler* assembler)
: assembler_(assembler),
current_position_(RelocInfo::kNoPosition),
current_position_recording_type_(NORMAL_POSITION),
written_position_(RelocInfo::kNoPosition),
current_statement_position_(RelocInfo::kNoPosition),
written_statement_position_(RelocInfo::kNoPosition) { }
// Set current position to pos. If recording_type is FORCED_POSITION then
// WriteRecordedPositions will write this position even if it is equal to
// statement position previously written for another pc.
void RecordPosition(int pos,
PositionRecordingType recording_type = NORMAL_POSITION);
// Set current statement position to pos.
void RecordStatementPosition(int pos);
// Write recorded positions to relocation information.
bool WriteRecordedPositions();
int current_position() const { return current_position_; }
int current_statement_position() const { return current_statement_position_; }
private:
Assembler* assembler_;
int current_position_;
PositionRecordingType current_position_recording_type_;
int written_position_;
int current_statement_position_;
int written_statement_position_;
};
class PreserveStatementPositionScope BASE_EMBEDDED {
public:
explicit PreserveStatementPositionScope(PositionsRecorder* positions_recorder)
: positions_recorder_(positions_recorder),
statement_position_(positions_recorder->current_statement_position()) {}
~PreserveStatementPositionScope() {
if (statement_position_ != RelocInfo::kNoPosition) {
positions_recorder_->RecordStatementPosition(statement_position_);
}
}
private:
PositionsRecorder* positions_recorder_;
int statement_position_;
};
// -----------------------------------------------------------------------------
// Utility functions
static inline bool is_intn(int x, int n) {
return -(1 << (n-1)) <= x && x < (1 << (n-1));
}
static inline bool is_int8(int x) { return is_intn(x, 8); }
static inline bool is_int16(int x) { return is_intn(x, 16); }
static inline bool is_int18(int x) { return is_intn(x, 18); }
static inline bool is_int24(int x) { return is_intn(x, 24); }
static inline bool is_uintn(int x, int n) {
return (x & -(1 << n)) == 0;
}
static inline bool is_uint2(int x) { return is_uintn(x, 2); }
static inline bool is_uint3(int x) { return is_uintn(x, 3); }
static inline bool is_uint4(int x) { return is_uintn(x, 4); }
static inline bool is_uint5(int x) { return is_uintn(x, 5); }
static inline bool is_uint6(int x) { return is_uintn(x, 6); }
static inline bool is_uint8(int x) { return is_uintn(x, 8); }
static inline bool is_uint10(int x) { return is_uintn(x, 10); }
static inline bool is_uint12(int x) { return is_uintn(x, 12); }
static inline bool is_uint16(int x) { return is_uintn(x, 16); }
static inline bool is_uint24(int x) { return is_uintn(x, 24); }
static inline bool is_uint26(int x) { return is_uintn(x, 26); }
static inline bool is_uint28(int x) { return is_uintn(x, 28); }
static inline int NumberOfBitsSet(uint32_t x) {
unsigned int num_bits_set;
for (num_bits_set = 0; x; x >>= 1) {
num_bits_set += x & 1;
}
return num_bits_set;
}
} } // namespace v8::internal
#endif // V8_ASSEMBLER_H_