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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
*
* Copyright 2021 Mozilla Foundation
*
* 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
*
*
* 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 wasm_codegen_types_h
#define wasm_codegen_types_h
#include "mozilla/EnumeratedArray.h"
#include "mozilla/PodOperations.h"
#include <stdint.h>
#include "jit/IonTypes.h"
#include "wasm/WasmBuiltins.h"
#include "wasm/WasmCodegenConstants.h"
#include "wasm/WasmConstants.h"
#include "wasm/WasmInstanceData.h"
#include "wasm/WasmSerialize.h"
#include "wasm/WasmTypeDef.h"
#include "wasm/WasmUtility.h"
namespace js {
namespace jit {
template <class VecT, class ABIArgGeneratorT>
class ABIArgIterBase;
} // namespace jit
namespace wasm {
using mozilla::EnumeratedArray;
struct ModuleEnvironment;
struct TableDesc;
struct V128;
// ArgTypeVector type.
//
// Functions usually receive one ABI argument per WebAssembly argument. However
// if a function has multiple results and some of those results go to the stack,
// then it additionally receives a synthetic ABI argument holding a pointer to
// the stack result area.
//
// Given the presence of synthetic arguments, sometimes we need a name for
// non-synthetic arguments. We call those "natural" arguments.
enum class StackResults { HasStackResults, NoStackResults };
class ArgTypeVector {
const ValTypeVector& args_;
bool hasStackResults_;
// To allow ABIArgIterBase<VecT, ABIArgGeneratorT>, we define a private
// length() method. To prevent accidental errors, other users need to be
// explicit and call lengthWithStackResults() or
// lengthWithoutStackResults().
size_t length() const { return args_.length() + size_t(hasStackResults_); }
template <class VecT, class ABIArgGeneratorT>
friend class jit::ABIArgIterBase;
public:
ArgTypeVector(const ValTypeVector& args, StackResults stackResults)
: args_(args),
hasStackResults_(stackResults == StackResults::HasStackResults) {}
explicit ArgTypeVector(const FuncType& funcType);
bool hasSyntheticStackResultPointerArg() const { return hasStackResults_; }
StackResults stackResults() const {
return hasSyntheticStackResultPointerArg() ? StackResults::HasStackResults
: StackResults::NoStackResults;
}
size_t lengthWithoutStackResults() const { return args_.length(); }
bool isSyntheticStackResultPointerArg(size_t idx) const {
// The pointer to stack results area, if present, is a synthetic argument
// tacked on at the end.
MOZ_ASSERT(idx < lengthWithStackResults());
return idx == args_.length();
}
bool isNaturalArg(size_t idx) const {
return !isSyntheticStackResultPointerArg(idx);
}
size_t naturalIndex(size_t idx) const {
MOZ_ASSERT(isNaturalArg(idx));
// Because the synthetic argument, if present, is tacked on the end, an
// argument index that isn't synthetic is natural.
return idx;
}
size_t lengthWithStackResults() const { return length(); }
jit::MIRType operator[](size_t i) const {
MOZ_ASSERT(i < lengthWithStackResults());
if (isSyntheticStackResultPointerArg(i)) {
return jit::MIRType::StackResults;
}
return args_[naturalIndex(i)].toMIRType();
}
};
// A wrapper around the bytecode offset of a wasm instruction within a whole
// module, used for trap offsets or call offsets. These offsets should refer to
// the first byte of the instruction that triggered the trap / did the call and
// should ultimately derive from OpIter::bytecodeOffset.
class BytecodeOffset {
static const uint32_t INVALID = -1;
uint32_t offset_;
WASM_CHECK_CACHEABLE_POD(offset_);
public:
BytecodeOffset() : offset_(INVALID) {}
explicit BytecodeOffset(uint32_t offset) : offset_(offset) {}
bool isValid() const { return offset_ != INVALID; }
uint32_t offset() const {
MOZ_ASSERT(isValid());
return offset_;
}
};
WASM_DECLARE_CACHEABLE_POD(BytecodeOffset);
// A TrapMachineInsn describes roughly what kind of machine instruction has
// caused a trap. This is used only for validation of trap placement in debug
// builds, in ModuleGenerator::finishMetadataTier, and is not necessary for
// execution of wasm code.
enum class TrapMachineInsn {
// The "official" undefined insn for the target, or something equivalent
// that we use for that purpose. The key property is that it always raises
// SIGILL when executed. For example, UD2 on Intel.
OfficialUD,
// Loads and stores that move 8, 16, 32, 64 or 128 bits of data, regardless
// of their type and how they are subsequently used (widened or duplicated).
Load8,
Load16,
Load32,
Load64,
Load128,
Store8,
Store16,
Store32,
Store64,
Store128,
// Any kind of atomic r-m-w or CAS memory transaction, but not including
// Load-Linked or Store-Checked style insns -- those count as plain LoadX
// and StoreX.
Atomic
};
static inline TrapMachineInsn TrapMachineInsnForLoad(int byteSize) {
switch (byteSize) {
case 1:
return TrapMachineInsn::Load8;
case 2:
return TrapMachineInsn::Load16;
case 4:
return TrapMachineInsn::Load32;
case 8:
return TrapMachineInsn::Load64;
case 16:
return TrapMachineInsn::Load128;
default:
MOZ_CRASH("TrapMachineInsnForLoad");
}
}
static inline TrapMachineInsn TrapMachineInsnForLoadWord() {
return TrapMachineInsnForLoad(sizeof(void*));
}
static inline TrapMachineInsn TrapMachineInsnForStore(int byteSize) {
switch (byteSize) {
case 1:
return TrapMachineInsn::Store8;
case 2:
return TrapMachineInsn::Store16;
case 4:
return TrapMachineInsn::Store32;
case 8:
return TrapMachineInsn::Store64;
case 16:
return TrapMachineInsn::Store128;
default:
MOZ_CRASH("TrapMachineInsnForStore");
}
}
static inline TrapMachineInsn TrapMachineInsnForStoreWord() {
return TrapMachineInsnForStore(sizeof(void*));
}
#ifdef DEBUG
const char* NameOfTrap(Trap trap);
const char* NameOfTrapMachineInsn(TrapMachineInsn tmi);
#endif // DEBUG
// This holds an assembler buffer offset, which indicates the offset of a
// faulting instruction, and is used for the construction of TrapSites below.
// It is wrapped up as a new type only to avoid getting it confused with any
// other uint32_t or with CodeOffset.
class FaultingCodeOffset {
static constexpr uint32_t INVALID = UINT32_MAX;
uint32_t offset_;
public:
FaultingCodeOffset() : offset_(INVALID) {}
explicit FaultingCodeOffset(uint32_t offset) : offset_(offset) {
MOZ_ASSERT(offset != INVALID);
}
bool isValid() const { return offset_ != INVALID; }
uint32_t get() const {
MOZ_ASSERT(isValid());
return offset_;
}
};
static_assert(sizeof(FaultingCodeOffset) == 4);
// And this holds two such offsets. Needed for 64-bit integer transactions on
// 32-bit targets.
using FaultingCodeOffsetPair =
std::pair<FaultingCodeOffset, FaultingCodeOffset>;
static_assert(sizeof(FaultingCodeOffsetPair) == 8);
// A TrapSite (in the TrapSiteVector for a given Trap code) represents a wasm
// instruction at a given bytecode offset that can fault at the given pc
// offset. When such a fault occurs, a signal/exception handler looks up the
// TrapSite to confirm the fault is intended/safe and redirects pc to the trap
// stub.
struct TrapSite {
#ifdef DEBUG
TrapMachineInsn insn;
#endif
uint32_t pcOffset;
BytecodeOffset bytecode;
WASM_CHECK_CACHEABLE_POD(pcOffset, bytecode);
TrapSite()
:
#ifdef DEBUG
insn(TrapMachineInsn::OfficialUD),
#endif
pcOffset(-1) {
}
TrapSite(TrapMachineInsn insn, FaultingCodeOffset fco,
BytecodeOffset bytecode)
:
#ifdef DEBUG
insn(insn),
#endif
pcOffset(fco.get()),
bytecode(bytecode) {
}
void offsetBy(uint32_t offset) { pcOffset += offset; }
};
WASM_DECLARE_CACHEABLE_POD(TrapSite);
WASM_DECLARE_POD_VECTOR(TrapSite, TrapSiteVector)
struct TrapSiteVectorArray
: EnumeratedArray<Trap, TrapSiteVector, size_t(Trap::Limit)> {
bool empty() const;
void clear();
void swap(TrapSiteVectorArray& rhs);
void shrinkStorageToFit();
size_t sumOfLengths() const;
size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
};
// On trap, the bytecode offset to be reported in callstacks is saved.
struct TrapData {
// The resumePC indicates where, if the trap doesn't throw, the trap stub
// should jump to after restoring all register state.
void* resumePC;
// The unwoundPC is the PC after adjustment by wasm::StartUnwinding(), which
// basically unwinds partially-construted wasm::Frames when pc is in the
// prologue/epilogue. Stack traces during a trap should use this PC since
// it corresponds to the JitActivation::wasmExitFP.
void* unwoundPC;
Trap trap;
uint32_t bytecodeOffset;
// A return_call_indirect from the first function in an activation into
// a signature mismatch may leave us with only one frame. This frame is
// validly constructed, but has no debug frame yet.
bool failedUnwindSignatureMismatch;
};
// The (,Callable,Func)Offsets classes are used to record the offsets of
// different key points in a CodeRange during compilation.
struct Offsets {
explicit Offsets(uint32_t begin = 0, uint32_t end = 0)
: begin(begin), end(end) {}
// These define a [begin, end) contiguous range of instructions compiled
// into a CodeRange.
uint32_t begin;
uint32_t end;
WASM_CHECK_CACHEABLE_POD(begin, end);
};
WASM_DECLARE_CACHEABLE_POD(Offsets);
struct CallableOffsets : Offsets {
MOZ_IMPLICIT CallableOffsets(uint32_t ret = 0) : ret(ret) {}
// The offset of the return instruction precedes 'end' by a variable number
// of instructions due to out-of-line codegen.
uint32_t ret;
WASM_CHECK_CACHEABLE_POD_WITH_PARENT(Offsets, ret);
};
WASM_DECLARE_CACHEABLE_POD(CallableOffsets);
struct FuncOffsets : CallableOffsets {
MOZ_IMPLICIT FuncOffsets() : uncheckedCallEntry(0), tierEntry(0) {}
// Function CodeRanges have a checked call entry which takes an extra
// signature argument which is checked against the callee's signature before
// falling through to the normal prologue. The checked call entry is thus at
// the beginning of the CodeRange and the unchecked call entry is at some
// offset after the checked call entry.
//
// Note that there won't always be a checked call entry because not all
// functions require them. See GenerateFunctionPrologue.
uint32_t uncheckedCallEntry;
// The tierEntry is the point within a function to which the patching code
// within a Tier-1 function jumps. It could be the instruction following
// the jump in the Tier-1 function, or the point following the standard
// prologue within a Tier-2 function.
uint32_t tierEntry;
WASM_CHECK_CACHEABLE_POD_WITH_PARENT(CallableOffsets, uncheckedCallEntry,
tierEntry);
};
WASM_DECLARE_CACHEABLE_POD(FuncOffsets);
using FuncOffsetsVector = Vector<FuncOffsets, 0, SystemAllocPolicy>;
// A CodeRange describes a single contiguous range of code within a wasm
// module's code segment. A CodeRange describes what the code does and, for
// function bodies, the name and source coordinates of the function.
class CodeRange {
public:
enum Kind {
Function, // function definition
InterpEntry, // calls into wasm from C++
JitEntry, // calls into wasm from jit code
ImportInterpExit, // slow-path calling from wasm into C++ interp
ImportJitExit, // fast-path calling from wasm into jit code
BuiltinThunk, // fast-path calling from wasm into a C++ native
TrapExit, // calls C++ to report and jumps to throw stub
DebugTrap, // calls C++ to handle debug event
FarJumpIsland, // inserted to connect otherwise out-of-range insns
Throw // special stack-unwinding stub jumped to by other stubs
};
private:
// All fields are treated as cacheable POD:
uint32_t begin_;
uint32_t ret_;
uint32_t end_;
union {
struct {
uint32_t funcIndex_;
union {
struct {
uint32_t lineOrBytecode_;
uint16_t beginToUncheckedCallEntry_;
uint16_t beginToTierEntry_;
bool hasUnwindInfo_;
} func;
};
};
Trap trap_;
} u;
Kind kind_ : 8;
WASM_CHECK_CACHEABLE_POD(begin_, ret_, end_, u.funcIndex_,
u.func.lineOrBytecode_,
u.func.beginToUncheckedCallEntry_,
u.func.beginToTierEntry_, u.func.hasUnwindInfo_,
u.trap_, kind_);
public:
CodeRange() = default;
CodeRange(Kind kind, Offsets offsets);
CodeRange(Kind kind, uint32_t funcIndex, Offsets offsets);
CodeRange(Kind kind, CallableOffsets offsets);
CodeRange(Kind kind, uint32_t funcIndex, CallableOffsets);
CodeRange(uint32_t funcIndex, uint32_t lineOrBytecode, FuncOffsets offsets,
bool hasUnwindInfo);
void offsetBy(uint32_t offset) {
begin_ += offset;
end_ += offset;
if (hasReturn()) {
ret_ += offset;
}
}
// All CodeRanges have a begin and end.
uint32_t begin() const { return begin_; }
uint32_t end() const { return end_; }
// Other fields are only available for certain CodeRange::Kinds.
Kind kind() const { return kind_; }
bool isFunction() const { return kind() == Function; }
bool isImportExit() const {
return kind() == ImportJitExit || kind() == ImportInterpExit ||
kind() == BuiltinThunk;
}
bool isImportInterpExit() const { return kind() == ImportInterpExit; }
bool isImportJitExit() const { return kind() == ImportJitExit; }
bool isTrapExit() const { return kind() == TrapExit; }
bool isDebugTrap() const { return kind() == DebugTrap; }
bool isThunk() const { return kind() == FarJumpIsland; }
// Functions, import exits, trap exits and JitEntry stubs have standard
// callable prologues and epilogues. Asynchronous frame iteration needs to
// know the offset of the return instruction to calculate the frame pointer.
bool hasReturn() const {
return isFunction() || isImportExit() || isDebugTrap() || isJitEntry();
}
uint32_t ret() const {
MOZ_ASSERT(hasReturn());
return ret_;
}
// Functions, export stubs and import stubs all have an associated function
// index.
bool isJitEntry() const { return kind() == JitEntry; }
bool isInterpEntry() const { return kind() == InterpEntry; }
bool isEntry() const { return isInterpEntry() || isJitEntry(); }
bool hasFuncIndex() const {
return isFunction() || isImportExit() || isEntry();
}
uint32_t funcIndex() const {
MOZ_ASSERT(hasFuncIndex());
return u.funcIndex_;
}
// TrapExit CodeRanges have a Trap field.
Trap trap() const {
MOZ_ASSERT(isTrapExit());
return u.trap_;
}
// Function CodeRanges have two entry points: one for normal calls (with a
// known signature) and one for table calls (which involves dynamic
// signature checking).
uint32_t funcCheckedCallEntry() const {
MOZ_ASSERT(isFunction());
// not all functions have the checked call prologue;
// see GenerateFunctionPrologue
MOZ_ASSERT(u.func.beginToUncheckedCallEntry_ != 0);
return begin_;
}
uint32_t funcUncheckedCallEntry() const {
MOZ_ASSERT(isFunction());
return begin_ + u.func.beginToUncheckedCallEntry_;
}
uint32_t funcTierEntry() const {
MOZ_ASSERT(isFunction());
return begin_ + u.func.beginToTierEntry_;
}
uint32_t funcLineOrBytecode() const {
MOZ_ASSERT(isFunction());
return u.func.lineOrBytecode_;
}
bool funcHasUnwindInfo() const {
MOZ_ASSERT(isFunction());
return u.func.hasUnwindInfo_;
}
// A sorted array of CodeRanges can be looked up via BinarySearch and
// OffsetInCode.
struct OffsetInCode {
size_t offset;
explicit OffsetInCode(size_t offset) : offset(offset) {}
bool operator==(const CodeRange& rhs) const {
return offset >= rhs.begin() && offset < rhs.end();
}
bool operator<(const CodeRange& rhs) const { return offset < rhs.begin(); }
};
};
WASM_DECLARE_CACHEABLE_POD(CodeRange);
WASM_DECLARE_POD_VECTOR(CodeRange, CodeRangeVector)
extern const CodeRange* LookupInSorted(const CodeRangeVector& codeRanges,
CodeRange::OffsetInCode target);
// While the frame-pointer chain allows the stack to be unwound without
// metadata, Error.stack still needs to know the line/column of every call in
// the chain. A CallSiteDesc describes a single callsite to which CallSite adds
// the metadata necessary to walk up to the next frame. Lastly CallSiteAndTarget
// adds the function index of the callee.
class CallSiteDesc {
static constexpr size_t LINE_OR_BYTECODE_BITS_SIZE = 28;
uint32_t lineOrBytecode_ : LINE_OR_BYTECODE_BITS_SIZE;
uint32_t kind_ : 4;
WASM_CHECK_CACHEABLE_POD(lineOrBytecode_, kind_);
public:
static constexpr uint32_t MAX_LINE_OR_BYTECODE_VALUE =
(1 << LINE_OR_BYTECODE_BITS_SIZE) - 1;
enum Kind {
Func, // pc-relative call to a specific function
Import, // wasm import call
Indirect, // dynamic callee called via register, context on stack
IndirectFast, // dynamically determined to be same-instance
FuncRef, // call using direct function reference
FuncRefFast, // call using direct function reference within same-instance
ReturnFunc, // return call to a specific function
ReturnStub, // return call trampoline
Symbolic, // call to a single symbolic callee
EnterFrame, // call to a enter frame handler
LeaveFrame, // call to a leave frame handler
CollapseFrame, // call to a leave frame handler during tail call
Breakpoint // call to instruction breakpoint
};
CallSiteDesc() : lineOrBytecode_(0), kind_(0) {}
explicit CallSiteDesc(Kind kind) : lineOrBytecode_(0), kind_(kind) {
MOZ_ASSERT(kind == Kind(kind_));
}
CallSiteDesc(uint32_t lineOrBytecode, Kind kind)
: lineOrBytecode_(lineOrBytecode), kind_(kind) {
MOZ_ASSERT(kind == Kind(kind_));
MOZ_ASSERT(lineOrBytecode == lineOrBytecode_);
}
CallSiteDesc(BytecodeOffset bytecodeOffset, Kind kind)
: lineOrBytecode_(bytecodeOffset.offset()), kind_(kind) {
MOZ_ASSERT(kind == Kind(kind_));
MOZ_ASSERT(bytecodeOffset.offset() == lineOrBytecode_);
}
uint32_t lineOrBytecode() const { return lineOrBytecode_; }
Kind kind() const { return Kind(kind_); }
bool isImportCall() const { return kind() == CallSiteDesc::Import; }
bool isIndirectCall() const { return kind() == CallSiteDesc::Indirect; }
bool isFuncRefCall() const { return kind() == CallSiteDesc::FuncRef; }
bool isReturnStub() const { return kind() == CallSiteDesc::ReturnStub; }
bool mightBeCrossInstance() const {
return isImportCall() || isIndirectCall() || isFuncRefCall() ||
isReturnStub();
}
};
static_assert(js::wasm::MaxFunctionBytes <=
CallSiteDesc::MAX_LINE_OR_BYTECODE_VALUE);
WASM_DECLARE_CACHEABLE_POD(CallSiteDesc);
class CallSite : public CallSiteDesc {
uint32_t returnAddressOffset_;
WASM_CHECK_CACHEABLE_POD_WITH_PARENT(CallSiteDesc, returnAddressOffset_);
public:
CallSite() : returnAddressOffset_(0) {}
CallSite(CallSiteDesc desc, uint32_t returnAddressOffset)
: CallSiteDesc(desc), returnAddressOffset_(returnAddressOffset) {}
void offsetBy(uint32_t delta) { returnAddressOffset_ += delta; }
uint32_t returnAddressOffset() const { return returnAddressOffset_; }
};
WASM_DECLARE_CACHEABLE_POD(CallSite);
WASM_DECLARE_POD_VECTOR(CallSite, CallSiteVector)
// A CallSiteTarget describes the callee of a CallSite, either a function or a
// trap exit. Although checked in debug builds, a CallSiteTarget doesn't
// officially know whether it targets a function or trap, relying on the Kind of
// the CallSite to discriminate.
class CallSiteTarget {
uint32_t packed_;
WASM_CHECK_CACHEABLE_POD(packed_);
#ifdef DEBUG
enum Kind { None, FuncIndex, TrapExit } kind_;
WASM_CHECK_CACHEABLE_POD(kind_);
#endif
public:
explicit CallSiteTarget()
: packed_(UINT32_MAX)
#ifdef DEBUG
,
kind_(None)
#endif
{
}
explicit CallSiteTarget(uint32_t funcIndex)
: packed_(funcIndex)
#ifdef DEBUG
,
kind_(FuncIndex)
#endif
{
}
explicit CallSiteTarget(Trap trap)
: packed_(uint32_t(trap))
#ifdef DEBUG
,
kind_(TrapExit)
#endif
{
}
uint32_t funcIndex() const {
MOZ_ASSERT(kind_ == FuncIndex);
return packed_;
}
Trap trap() const {
MOZ_ASSERT(kind_ == TrapExit);
MOZ_ASSERT(packed_ < uint32_t(Trap::Limit));
return Trap(packed_);
}
};
WASM_DECLARE_CACHEABLE_POD(CallSiteTarget);
using CallSiteTargetVector = Vector<CallSiteTarget, 0, SystemAllocPolicy>;
// TryNotes are stored in a vector that acts as an exception table for
// wasm try-catch blocks. These represent the information needed to take
// exception handling actions after a throw is executed.
struct TryNote {
private:
// Sentinel value to detect a try note that has not been given a try body.
static const uint32_t BEGIN_NONE = UINT32_MAX;
// Sentinel value used in `entryPointOrIsDelegate_`.
static const uint32_t IS_DELEGATE = UINT32_MAX;
// Begin code offset of the try body.
uint32_t begin_;
// Exclusive end code offset of the try body.
uint32_t end_;
// Either a marker that this is a 'delegate' or else the code offset of the
// landing pad to jump to.
uint32_t entryPointOrIsDelegate_;
// If this is a delegate, then this is the code offset to delegate to,
// otherwise this is the offset from the frame pointer of the stack pointer
// to use when jumping to the landing pad.
uint32_t framePushedOrDelegateOffset_;
WASM_CHECK_CACHEABLE_POD(begin_, end_, entryPointOrIsDelegate_,
framePushedOrDelegateOffset_);
public:
explicit TryNote()
: begin_(BEGIN_NONE),
end_(0),
entryPointOrIsDelegate_(0),
framePushedOrDelegateOffset_(0) {}
// Returns whether a try note has been assigned a range for the try body.
bool hasTryBody() const { return begin_ != BEGIN_NONE; }
// The code offset of the beginning of the try body.
uint32_t tryBodyBegin() const { return begin_; }
// The code offset of the exclusive end of the try body.
uint32_t tryBodyEnd() const { return end_; }
// Returns whether an offset is within this try note's body.
bool offsetWithinTryBody(uint32_t offset) const {
return offset > begin_ && offset <= end_;
}
// Check if the unwinder should delegate the handling of this try note to the
// try note given at the delegate offset.
bool isDelegate() const { return entryPointOrIsDelegate_ == IS_DELEGATE; }
// The code offset to delegate the handling of this try note to.
uint32_t delegateOffset() const {
MOZ_ASSERT(isDelegate());
return framePushedOrDelegateOffset_;
}
// The code offset of the entry to the landing pad.
uint32_t landingPadEntryPoint() const {
MOZ_ASSERT(!isDelegate());
return entryPointOrIsDelegate_;
}
// The stack frame pushed amount at the entry to the landing pad.
uint32_t landingPadFramePushed() const {
MOZ_ASSERT(!isDelegate());
return framePushedOrDelegateOffset_;
}
// Set the beginning of the try body.
void setTryBodyBegin(uint32_t begin) {
// There must not be a begin to the try body yet
MOZ_ASSERT(begin_ == BEGIN_NONE);
begin_ = begin;
}
// Set the end of the try body.
void setTryBodyEnd(uint32_t end) {
// There must be a begin to the try body
MOZ_ASSERT(begin_ != BEGIN_NONE);
end_ = end;
// We do not allow empty try bodies
MOZ_ASSERT(end_ > begin_);
}
// Mark this try note as a delegate, requesting the unwinder to use the try
// note found at the delegate offset.
void setDelegate(uint32_t delegateOffset) {
entryPointOrIsDelegate_ = IS_DELEGATE;
framePushedOrDelegateOffset_ = delegateOffset;
}
// Set the entry point and frame pushed of the landing pad.
void setLandingPad(uint32_t entryPoint, uint32_t framePushed) {
MOZ_ASSERT(!isDelegate());
entryPointOrIsDelegate_ = entryPoint;
framePushedOrDelegateOffset_ = framePushed;
}
// Adjust all code offsets in this try note by a delta.
void offsetBy(uint32_t offset) {
begin_ += offset;
end_ += offset;
if (isDelegate()) {
framePushedOrDelegateOffset_ += offset;
} else {
entryPointOrIsDelegate_ += offset;
}
}
bool operator<(const TryNote& other) const {
// Special case comparison with self. This avoids triggering the assertion
// about non-intersection below. This case can arise in std::sort.
if (this == &other) {
return false;
}
// Try notes must be properly nested without touching at begin and end
MOZ_ASSERT(end_ <= other.begin_ || begin_ >= other.end_ ||
(begin_ > other.begin_ && end_ < other.end_) ||
(other.begin_ > begin_ && other.end_ < end_));
// A total order is therefore given solely by comparing end points. This
// order will be such that the first try note to intersect a point is the
// innermost try note for that point.
return end_ < other.end_;
}
};
WASM_DECLARE_CACHEABLE_POD(TryNote);
WASM_DECLARE_POD_VECTOR(TryNote, TryNoteVector)
class CodeRangeUnwindInfo {
public:
enum UnwindHow {
Normal,
RestoreFpRa,
RestoreFp,
UseFpLr,
UseFp,
};
private:
uint32_t offset_;
UnwindHow unwindHow_;
WASM_CHECK_CACHEABLE_POD(offset_, unwindHow_);
public:
CodeRangeUnwindInfo(uint32_t offset, UnwindHow unwindHow)
: offset_(offset), unwindHow_(unwindHow) {}
uint32_t offset() const { return offset_; }
UnwindHow unwindHow() const { return unwindHow_; }
// Adjust all code offsets in this info by a delta.
void offsetBy(uint32_t offset) { offset_ += offset; }
};
WASM_DECLARE_CACHEABLE_POD(CodeRangeUnwindInfo);
WASM_DECLARE_POD_VECTOR(CodeRangeUnwindInfo, CodeRangeUnwindInfoVector)
enum class CallIndirectIdKind {
// Generate a no-op signature check prologue, asm.js function tables are
// homogenous.
AsmJS,
// Use a machine code immediate for the signature check, only works on simple
// function types, without super types, and without siblings in their
// recursion group.
Immediate,
// Use the full type definition and subtyping machinery when performing the
// signature check.
Global,
// Don't generate any signature check prologue, for functions that cannot be
// stored in tables.
None
};
// CallIndirectId describes how to compile a call_indirect and matching
// signature check in the function prologue for a given function type.
class CallIndirectId {
CallIndirectIdKind kind_;
union {
size_t immediate_;
struct {
size_t instanceDataOffset_;
bool hasSuperType_;
} global_;
};
explicit CallIndirectId(CallIndirectIdKind kind) : kind_(kind) {}
public:
CallIndirectId() : kind_(CallIndirectIdKind::None) {}
// Get a CallIndirectId for an asm.js function which will generate a no-op
// checked call prologue.
static CallIndirectId forAsmJSFunc();
// Get the CallIndirectId for a function in a specific module.
static CallIndirectId forFunc(const ModuleEnvironment& moduleEnv,
uint32_t funcIndex);
// Get the CallIndirectId for a function type in a specific module.
static CallIndirectId forFuncType(const ModuleEnvironment& moduleEnv,
uint32_t funcTypeIndex);
CallIndirectIdKind kind() const { return kind_; }
bool isGlobal() const { return kind_ == CallIndirectIdKind::Global; }
// The bit-packed representation of simple function types. See FuncType in
// WasmTypeDef.h for more information.
uint32_t immediate() const {
MOZ_ASSERT(kind_ == CallIndirectIdKind::Immediate);
return immediate_;
}
// The offset of the TypeDefInstanceData for the function type.
uint32_t instanceDataOffset() const {
MOZ_ASSERT(kind_ == CallIndirectIdKind::Global);
return global_.instanceDataOffset_;
}
// Whether the TypeDef has any super types.
bool hasSuperType() const {
MOZ_ASSERT(kind_ == CallIndirectIdKind::Global);
return global_.hasSuperType_;
}
};
// CalleeDesc describes how to compile one of the variety of asm.js/wasm calls.
// This is hoisted into WasmCodegenTypes.h for sharing between Ion and Baseline.
class CalleeDesc {
public:
enum Which {
// Calls a function defined in the same module by its index.
Func,
// Calls the import identified by the offset of its FuncImportInstanceData
// in
// thread-local data.
Import,
// Calls a WebAssembly table (heterogeneous, index must be bounds
// checked, callee instance depends on TableDesc).
WasmTable,
// Calls an asm.js table (homogeneous, masked index, same-instance).
AsmJSTable,
// Call a C++ function identified by SymbolicAddress.
Builtin,
// Like Builtin, but automatically passes Instance* as first argument.
BuiltinInstanceMethod,
// Calls a function reference.
FuncRef,
};
private:
// which_ shall be initialized in the static constructors
MOZ_INIT_OUTSIDE_CTOR Which which_;
union U {
U() : funcIndex_(0) {}
uint32_t funcIndex_;
struct {
uint32_t instanceDataOffset_;
} import;
struct {
uint32_t instanceDataOffset_;
uint32_t minLength_;
Maybe<uint32_t> maxLength_;
CallIndirectId callIndirectId_;
} table;
SymbolicAddress builtin_;
} u;
public:
CalleeDesc() = default;
static CalleeDesc function(uint32_t funcIndex);
static CalleeDesc import(uint32_t instanceDataOffset);
static CalleeDesc wasmTable(const ModuleEnvironment& moduleEnv,
const TableDesc& desc, uint32_t tableIndex,
CallIndirectId callIndirectId);
static CalleeDesc asmJSTable(const ModuleEnvironment& moduleEnv,
uint32_t tableIndex);
static CalleeDesc builtin(SymbolicAddress callee);
static CalleeDesc builtinInstanceMethod(SymbolicAddress callee);
static CalleeDesc wasmFuncRef();
Which which() const { return which_; }
uint32_t funcIndex() const {
MOZ_ASSERT(which_ == Func);
return u.funcIndex_;
}
uint32_t importInstanceDataOffset() const {
MOZ_ASSERT(which_ == Import);
return u.import.instanceDataOffset_;
}
bool isTable() const { return which_ == WasmTable || which_ == AsmJSTable; }
uint32_t tableLengthInstanceDataOffset() const {
MOZ_ASSERT(isTable());
return u.table.instanceDataOffset_ + offsetof(TableInstanceData, length);
}
uint32_t tableFunctionBaseInstanceDataOffset() const {
MOZ_ASSERT(isTable());
return u.table.instanceDataOffset_ + offsetof(TableInstanceData, elements);
}
CallIndirectId wasmTableSigId() const {
MOZ_ASSERT(which_ == WasmTable);
return u.table.callIndirectId_;
}
uint32_t wasmTableMinLength() const {
MOZ_ASSERT(which_ == WasmTable);
return u.table.minLength_;
}
Maybe<uint32_t> wasmTableMaxLength() const {
MOZ_ASSERT(which_ == WasmTable);
return u.table.maxLength_;
}
SymbolicAddress builtin() const {
MOZ_ASSERT(which_ == Builtin || which_ == BuiltinInstanceMethod);
return u.builtin_;
}
bool isFuncRef() const { return which_ == FuncRef; }
};
} // namespace wasm
} // namespace js
#endif // wasm_codegen_types_h