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compiler.go
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compiler.go
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package wazeroir
import (
"bytes"
"encoding/binary"
"fmt"
"math"
"strings"
"github.com/tetratelabs/wazero/api"
"github.com/tetratelabs/wazero/internal/leb128"
"github.com/tetratelabs/wazero/internal/wasm"
)
type controlFrameKind byte
const (
controlFrameKindBlockWithContinuationLabel controlFrameKind = iota
controlFrameKindBlockWithoutContinuationLabel
controlFrameKindFunction
controlFrameKindLoop
controlFrameKindIfWithElse
controlFrameKindIfWithoutElse
)
type (
controlFrame struct {
frameID uint32
// originalStackLen holds the number of values on the stack
// when Start executing this control frame minus params for the block.
originalStackLenWithoutParam int
blockType *wasm.FunctionType
kind controlFrameKind
}
controlFrames struct{ frames []controlFrame }
)
func (c *controlFrame) ensureContinuation() {
// Make sure that if the frame is block and doesn't have continuation,
// change the Kind so we can emit the continuation block
// later when we reach the End instruction of this frame.
if c.kind == controlFrameKindBlockWithoutContinuationLabel {
c.kind = controlFrameKindBlockWithContinuationLabel
}
}
func (c *controlFrame) asLabel() Label {
switch c.kind {
case controlFrameKindBlockWithContinuationLabel,
controlFrameKindBlockWithoutContinuationLabel:
return NewLabel(LabelKindContinuation, c.frameID)
case controlFrameKindLoop:
return NewLabel(LabelKindHeader, c.frameID)
case controlFrameKindFunction:
return NewLabel(LabelKindReturn, 0)
case controlFrameKindIfWithElse,
controlFrameKindIfWithoutElse:
return NewLabel(LabelKindContinuation, c.frameID)
}
panic(fmt.Sprintf("unreachable: a bug in wazeroir implementation: %v", c.kind))
}
func (c *controlFrames) functionFrame() *controlFrame {
// No need to check stack bound
// as we can assume that all the operations
// are valid thanks to validateFunction
// at module validation phase.
return &c.frames[0]
}
func (c *controlFrames) get(n int) *controlFrame {
// No need to check stack bound
// as we can assume that all the operations
// are valid thanks to validateFunction
// at module validation phase.
return &c.frames[len(c.frames)-n-1]
}
func (c *controlFrames) top() *controlFrame {
// No need to check stack bound
// as we can assume that all the operations
// are valid thanks to validateFunction
// at module validation phase.
return &c.frames[len(c.frames)-1]
}
func (c *controlFrames) empty() bool {
return len(c.frames) == 0
}
func (c *controlFrames) pop() (frame *controlFrame) {
// No need to check stack bound
// as we can assume that all the operations
// are valid thanks to validateFunction
// at module validation phase.
frame = c.top()
c.frames = c.frames[:len(c.frames)-1]
return
}
func (c *controlFrames) push(frame controlFrame) {
c.frames = append(c.frames, frame)
}
func (c *Compiler) initializeStack() {
// Reuse the existing slice.
c.localIndexToStackHeightInUint64 = c.localIndexToStackHeightInUint64[:0]
var current int
for _, lt := range c.sig.Params {
c.localIndexToStackHeightInUint64 = append(c.localIndexToStackHeightInUint64, current)
if lt == wasm.ValueTypeV128 {
current++
}
current++
}
if c.callFrameStackSizeInUint64 > 0 {
// We reserve the stack slots for result values below the return call frame slots.
if diff := c.sig.ResultNumInUint64 - c.sig.ParamNumInUint64; diff > 0 {
current += diff
}
}
// Non-func param locals Start after the return call frame.
current += c.callFrameStackSizeInUint64
for _, lt := range c.localTypes {
c.localIndexToStackHeightInUint64 = append(c.localIndexToStackHeightInUint64, current)
if lt == wasm.ValueTypeV128 {
current++
}
current++
}
// Push function arguments.
for _, t := range c.sig.Params {
c.stackPush(wasmValueTypeToUnsignedType(t))
}
if c.callFrameStackSizeInUint64 > 0 {
// Reserve the stack slots for results.
for i := 0; i < c.sig.ResultNumInUint64-c.sig.ParamNumInUint64; i++ {
c.stackPush(UnsignedTypeI64)
}
// Reserve the stack slots for call frame.
for i := 0; i < c.callFrameStackSizeInUint64; i++ {
c.stackPush(UnsignedTypeI64)
}
}
}
// Compiler is in charge of lowering raw Wasm function body to get CompilationResult.
// This is created per *wasm.Module and reused for all functions in it to reduce memory allocations.
type Compiler struct {
module *wasm.Module
enabledFeatures api.CoreFeatures
callFrameStackSizeInUint64 int
stack []UnsignedType
currentFrameID uint32
controlFrames controlFrames
unreachableState struct {
on bool
depth int
}
pc, currentOpPC uint64
result CompilationResult
// body holds the code for the function's body where Wasm instructions are stored.
body []byte
// sig is the function type of the target function.
sig *wasm.FunctionType
// localTypes holds the target function locals' value types except function params.
localTypes []wasm.ValueType
// localIndexToStackHeightInUint64 maps the local index (starting with function params) to the stack height
// where the local is places. This is the necessary mapping for functions who contain vector type locals.
localIndexToStackHeightInUint64 []int
// types hold all the function types in the module where the targe function exists.
types []wasm.FunctionType
// funcs holds the type indexes for all declared functions in the module where the target function exists.
funcs []uint32
// globals holds the global types for all declared globals in the module where the target function exists.
globals []wasm.GlobalType
// needSourceOffset is true if this module requires DWARF based stack trace.
needSourceOffset bool
// bodyOffsetInCodeSection is the offset of the body of this function in the original Wasm binary's code section.
bodyOffsetInCodeSection uint64
ensureTermination bool
// Pre-allocated bytes.Reader to be used in various places.
br *bytes.Reader
funcTypeToSigs funcTypeToIRSignatures
next int
}
//lint:ignore U1000 for debugging only.
func (c *Compiler) stackDump() string {
strs := make([]string, 0, len(c.stack))
for _, s := range c.stack {
strs = append(strs, s.String())
}
return "[" + strings.Join(strs, ", ") + "]"
}
func (c *Compiler) markUnreachable() {
c.unreachableState.on = true
}
func (c *Compiler) resetUnreachable() {
c.unreachableState.on = false
}
// MemoryType is the type of memory in a compiled module.
type MemoryType byte
const (
// MemoryTypeNone indicates there is no memory.
MemoryTypeNone MemoryType = iota
// MemoryTypeStandard indicates there is a non-shared memory.
MemoryTypeStandard
// MemoryTypeShared indicates there is a shared memory.
MemoryTypeShared
)
type CompilationResult struct {
// Operations holds wazeroir operations compiled from Wasm instructions in a Wasm function.
Operations []UnionOperation
// IROperationSourceOffsetsInWasmBinary is index-correlated with Operation and maps each operation to the corresponding source instruction's
// offset in the original WebAssembly binary.
// Non nil only when the given Wasm module has the DWARF section.
IROperationSourceOffsetsInWasmBinary []uint64
// LabelCallers maps Label to the number of callers to that label.
// Here "callers" means that the call-sites which jumps to the label with br, br_if or br_table
// instructions.
//
// Note: zero possible and allowed in wasm. e.g.
//
// (block
// (br 0)
// (block i32.const 1111)
// )
//
// This example the label corresponding to `(block i32.const 1111)` is never be reached at runtime because `br 0` exits the function before we reach there
LabelCallers map[Label]uint32
// UsesMemory is true if this function might use memory.
UsesMemory bool
// The following fields are per-module values, not per-function.
// Globals holds all the declarations of globals in the module from which this function is compiled.
Globals []wasm.GlobalType
// Functions holds all the declarations of function in the module from which this function is compiled, including itself.
Functions []wasm.Index
// Types holds all the types in the module from which this function is compiled.
Types []wasm.FunctionType
// Memory indicates the type of memory of the module.
Memory MemoryType
// HasTable is true if the module from which this function is compiled has table declaration.
HasTable bool
// HasDataInstances is true if the module has data instances which might be used by memory.init or data.drop instructions.
HasDataInstances bool
// HasDataInstances is true if the module has element instances which might be used by table.init or elem.drop instructions.
HasElementInstances bool
}
// NewCompiler returns the new *Compiler for the given parameters.
// Use Compiler.Next function to get compilation result per function.
func NewCompiler(enabledFeatures api.CoreFeatures, callFrameStackSizeInUint64 int, module *wasm.Module, ensureTermination bool) (*Compiler, error) {
functions, globals, mem, tables, err := module.AllDeclarations()
if err != nil {
return nil, err
}
hasTable, hasDataInstances, hasElementInstances := len(tables) > 0,
len(module.DataSection) > 0, len(module.ElementSection) > 0
var mt MemoryType
switch {
case mem == nil:
mt = MemoryTypeNone
case mem.IsShared:
mt = MemoryTypeShared
default:
mt = MemoryTypeStandard
}
types := module.TypeSection
c := &Compiler{
module: module,
enabledFeatures: enabledFeatures,
controlFrames: controlFrames{},
callFrameStackSizeInUint64: callFrameStackSizeInUint64,
result: CompilationResult{
Globals: globals,
Functions: functions,
Types: types,
Memory: mt,
HasTable: hasTable,
HasDataInstances: hasDataInstances,
HasElementInstances: hasElementInstances,
LabelCallers: map[Label]uint32{},
},
globals: globals,
funcs: functions,
types: types,
ensureTermination: ensureTermination,
br: bytes.NewReader(nil),
funcTypeToSigs: funcTypeToIRSignatures{
indirectCalls: make([]*signature, len(types)),
directCalls: make([]*signature, len(types)),
wasmTypes: types,
},
needSourceOffset: module.DWARFLines != nil,
}
return c, nil
}
// Next returns the next CompilationResult for this Compiler.
func (c *Compiler) Next() (*CompilationResult, error) {
funcIndex := c.next
code := &c.module.CodeSection[funcIndex]
sig := &c.types[c.module.FunctionSection[funcIndex]]
// Reset the previous result.
c.result.Operations = c.result.Operations[:0]
c.result.IROperationSourceOffsetsInWasmBinary = c.result.IROperationSourceOffsetsInWasmBinary[:0]
c.result.UsesMemory = false
// Clears the existing entries in LabelCallers.
for frameID := uint32(0); frameID <= c.currentFrameID; frameID++ {
for k := LabelKind(0); k < LabelKindNum; k++ {
delete(c.result.LabelCallers, NewLabel(k, frameID))
}
}
// Reset the previous states.
c.pc = 0
c.currentOpPC = 0
c.currentFrameID = 0
c.unreachableState.on, c.unreachableState.depth = false, 0
if err := c.compile(sig, code.Body, code.LocalTypes, code.BodyOffsetInCodeSection); err != nil {
return nil, err
}
c.next++
return &c.result, nil
}
// Compile lowers given function instance into wazeroir operations
// so that the resulting operations can be consumed by the interpreter
// or the Compiler compilation engine.
func (c *Compiler) compile(sig *wasm.FunctionType, body []byte, localTypes []wasm.ValueType, bodyOffsetInCodeSection uint64) error {
// Set function specific fields.
c.body = body
c.localTypes = localTypes
c.sig = sig
c.bodyOffsetInCodeSection = bodyOffsetInCodeSection
// Reuses the underlying slices.
c.stack = c.stack[:0]
c.controlFrames.frames = c.controlFrames.frames[:0]
c.initializeStack()
// Emit const expressions for locals.
// Note that here we don't take function arguments
// into account, meaning that callers must push
// arguments before entering into the function body.
for _, t := range c.localTypes {
c.emitDefaultValue(t)
}
// Insert the function control frame.
c.controlFrames.push(controlFrame{
frameID: c.nextFrameID(),
blockType: c.sig,
kind: controlFrameKindFunction,
})
// Now, enter the function body.
for !c.controlFrames.empty() && c.pc < uint64(len(c.body)) {
if err := c.handleInstruction(); err != nil {
return fmt.Errorf("handling instruction: %w", err)
}
}
return nil
}
// Translate the current Wasm instruction to wazeroir's operations,
// and emit the results into c.results.
func (c *Compiler) handleInstruction() error {
op := c.body[c.pc]
c.currentOpPC = c.pc
if false {
var instName string
if op == wasm.OpcodeVecPrefix {
instName = wasm.VectorInstructionName(c.body[c.pc+1])
} else if op == wasm.OpcodeAtomicPrefix {
instName = wasm.AtomicInstructionName(c.body[c.pc+1])
} else if op == wasm.OpcodeMiscPrefix {
instName = wasm.MiscInstructionName(c.body[c.pc+1])
} else {
instName = wasm.InstructionName(op)
}
fmt.Printf("handling %s, unreachable_state(on=%v,depth=%d), stack=%v\n",
instName, c.unreachableState.on, c.unreachableState.depth, c.stack,
)
}
var peekValueType UnsignedType
if len(c.stack) > 0 {
peekValueType = c.stackPeek()
}
// Modify the stack according the current instruction.
// Note that some instructions will read "index" in
// applyToStack and advance c.pc inside the function.
index, err := c.applyToStack(op)
if err != nil {
return fmt.Errorf("apply stack failed for %s: %w", wasm.InstructionName(op), err)
}
// Now we handle each instruction, and
// emit the corresponding wazeroir operations to the results.
operatorSwitch:
switch op {
case wasm.OpcodeUnreachable:
c.emit(NewOperationUnreachable())
c.markUnreachable()
case wasm.OpcodeNop:
// Nop is noop!
case wasm.OpcodeBlock:
c.br.Reset(c.body[c.pc+1:])
bt, num, err := wasm.DecodeBlockType(c.types, c.br, c.enabledFeatures)
if err != nil {
return fmt.Errorf("reading block type for block instruction: %w", err)
}
c.pc += num
if c.unreachableState.on {
// If it is currently in unreachable,
// just remove the entire block.
c.unreachableState.depth++
break operatorSwitch
}
// Create a new frame -- entering this block.
frame := controlFrame{
frameID: c.nextFrameID(),
originalStackLenWithoutParam: len(c.stack) - len(bt.Params),
kind: controlFrameKindBlockWithoutContinuationLabel,
blockType: bt,
}
c.controlFrames.push(frame)
case wasm.OpcodeLoop:
c.br.Reset(c.body[c.pc+1:])
bt, num, err := wasm.DecodeBlockType(c.types, c.br, c.enabledFeatures)
if err != nil {
return fmt.Errorf("reading block type for loop instruction: %w", err)
}
c.pc += num
if c.unreachableState.on {
// If it is currently in unreachable,
// just remove the entire block.
c.unreachableState.depth++
break operatorSwitch
}
// Create a new frame -- entering loop.
frame := controlFrame{
frameID: c.nextFrameID(),
originalStackLenWithoutParam: len(c.stack) - len(bt.Params),
kind: controlFrameKindLoop,
blockType: bt,
}
c.controlFrames.push(frame)
// Prep labels for inside and the continuation of this loop.
loopLabel := NewLabel(LabelKindHeader, frame.frameID)
c.result.LabelCallers[loopLabel]++
// Emit the branch operation to enter inside the loop.
c.emit(NewOperationBr(loopLabel))
c.emit(NewOperationLabel(loopLabel))
// Insert the exit code check on the loop header, which is the only necessary point in the function body
// to prevent infinite loop.
//
// Note that this is a little aggressive: this checks the exit code regardless the loop header is actually
// the loop. In other words, this checks even when no br/br_if/br_table instructions jumping to this loop
// exist. However, in reality, that shouldn't be an issue since such "noop" loop header will highly likely be
// optimized out by almost all guest language compilers which have the control flow optimization passes.
if c.ensureTermination {
c.emit(NewOperationBuiltinFunctionCheckExitCode())
}
case wasm.OpcodeIf:
c.br.Reset(c.body[c.pc+1:])
bt, num, err := wasm.DecodeBlockType(c.types, c.br, c.enabledFeatures)
if err != nil {
return fmt.Errorf("reading block type for if instruction: %w", err)
}
c.pc += num
if c.unreachableState.on {
// If it is currently in unreachable,
// just remove the entire block.
c.unreachableState.depth++
break operatorSwitch
}
// Create a new frame -- entering if.
frame := controlFrame{
frameID: c.nextFrameID(),
originalStackLenWithoutParam: len(c.stack) - len(bt.Params),
// Note this will be set to controlFrameKindIfWithElse
// when else opcode found later.
kind: controlFrameKindIfWithoutElse,
blockType: bt,
}
c.controlFrames.push(frame)
// Prep labels for if and else of this if.
thenLabel := NewLabel(LabelKindHeader, frame.frameID)
elseLabel := NewLabel(LabelKindElse, frame.frameID)
c.result.LabelCallers[thenLabel]++
c.result.LabelCallers[elseLabel]++
// Emit the branch operation to enter the then block.
c.emit(NewOperationBrIf(thenLabel, elseLabel, NopInclusiveRange))
c.emit(NewOperationLabel(thenLabel))
case wasm.OpcodeElse:
frame := c.controlFrames.top()
if c.unreachableState.on && c.unreachableState.depth > 0 {
// If it is currently in unreachable, and the nested if,
// just remove the entire else block.
break operatorSwitch
} else if c.unreachableState.on {
// If it is currently in unreachable, and the non-nested if,
// reset the stack so we can correctly handle the else block.
top := c.controlFrames.top()
c.stack = c.stack[:top.originalStackLenWithoutParam]
top.kind = controlFrameKindIfWithElse
// Re-push the parameters to the if block so that else block can use them.
for _, t := range frame.blockType.Params {
c.stackPush(wasmValueTypeToUnsignedType(t))
}
// We are no longer unreachable in else frame,
// so emit the correct label, and reset the unreachable state.
elseLabel := NewLabel(LabelKindElse, frame.frameID)
c.resetUnreachable()
c.emit(
NewOperationLabel(elseLabel),
)
break operatorSwitch
}
// Change the Kind of this If block, indicating that
// the if has else block.
frame.kind = controlFrameKindIfWithElse
// We need to reset the stack so that
// the values pushed inside the then block
// do not affect the else block.
dropOp := NewOperationDrop(c.getFrameDropRange(frame, false))
// Reset the stack manipulated by the then block, and re-push the block param types to the stack.
c.stack = c.stack[:frame.originalStackLenWithoutParam]
for _, t := range frame.blockType.Params {
c.stackPush(wasmValueTypeToUnsignedType(t))
}
// Prep labels for else and the continuation of this if block.
elseLabel := NewLabel(LabelKindElse, frame.frameID)
continuationLabel := NewLabel(LabelKindContinuation, frame.frameID)
c.result.LabelCallers[continuationLabel]++
// Emit the instructions for exiting the if loop,
// and then the initiation of else block.
c.emit(dropOp)
// Jump to the continuation of this block.
c.emit(NewOperationBr(continuationLabel))
// Initiate the else block.
c.emit(NewOperationLabel(elseLabel))
case wasm.OpcodeEnd:
if c.unreachableState.on && c.unreachableState.depth > 0 {
c.unreachableState.depth--
break operatorSwitch
} else if c.unreachableState.on {
c.resetUnreachable()
frame := c.controlFrames.pop()
if c.controlFrames.empty() {
return nil
}
c.stack = c.stack[:frame.originalStackLenWithoutParam]
for _, t := range frame.blockType.Results {
c.stackPush(wasmValueTypeToUnsignedType(t))
}
continuationLabel := NewLabel(LabelKindContinuation, frame.frameID)
if frame.kind == controlFrameKindIfWithoutElse {
// Emit the else label.
elseLabel := NewLabel(LabelKindElse, frame.frameID)
c.result.LabelCallers[continuationLabel]++
c.emit(NewOperationLabel(elseLabel))
c.emit(NewOperationBr(continuationLabel))
c.emit(NewOperationLabel(continuationLabel))
} else {
c.emit(
NewOperationLabel(continuationLabel),
)
}
break operatorSwitch
}
frame := c.controlFrames.pop()
// We need to reset the stack so that
// the values pushed inside the block.
dropOp := NewOperationDrop(c.getFrameDropRange(frame, true))
c.stack = c.stack[:frame.originalStackLenWithoutParam]
// Push the result types onto the stack.
for _, t := range frame.blockType.Results {
c.stackPush(wasmValueTypeToUnsignedType(t))
}
// Emit the instructions according to the Kind of the current control frame.
switch frame.kind {
case controlFrameKindFunction:
if !c.controlFrames.empty() {
// Should never happen. If so, there's a bug in the translation.
panic("bug: found more function control frames")
}
// Return from function.
c.emit(dropOp)
c.emit(NewOperationBr(NewLabel(LabelKindReturn, 0)))
case controlFrameKindIfWithoutElse:
// This case we have to emit "empty" else label.
elseLabel := NewLabel(LabelKindElse, frame.frameID)
continuationLabel := NewLabel(LabelKindContinuation, frame.frameID)
c.result.LabelCallers[continuationLabel] += 2
c.emit(dropOp)
c.emit(NewOperationBr(continuationLabel))
// Emit the else which soon branches into the continuation.
c.emit(NewOperationLabel(elseLabel))
c.emit(NewOperationBr(continuationLabel))
// Initiate the continuation.
c.emit(NewOperationLabel(continuationLabel))
case controlFrameKindBlockWithContinuationLabel,
controlFrameKindIfWithElse:
continuationLabel := NewLabel(LabelKindContinuation, frame.frameID)
c.result.LabelCallers[continuationLabel]++
c.emit(dropOp)
c.emit(NewOperationBr(continuationLabel))
c.emit(NewOperationLabel(continuationLabel))
case controlFrameKindLoop, controlFrameKindBlockWithoutContinuationLabel:
c.emit(
dropOp,
)
default:
// Should never happen. If so, there's a bug in the translation.
panic(fmt.Errorf("bug: invalid control frame Kind: 0x%x", frame.kind))
}
case wasm.OpcodeBr:
targetIndex, n, err := leb128.LoadUint32(c.body[c.pc+1:])
if err != nil {
return fmt.Errorf("read the target for br_if: %w", err)
}
c.pc += n
if c.unreachableState.on {
// If it is currently in unreachable, br is no-op.
break operatorSwitch
}
targetFrame := c.controlFrames.get(int(targetIndex))
targetFrame.ensureContinuation()
dropOp := NewOperationDrop(c.getFrameDropRange(targetFrame, false))
targetID := targetFrame.asLabel()
c.result.LabelCallers[targetID]++
c.emit(dropOp)
c.emit(NewOperationBr(targetID))
// Br operation is stack-polymorphic, and mark the state as unreachable.
// That means subsequent instructions in the current control frame are "unreachable"
// and can be safely removed.
c.markUnreachable()
case wasm.OpcodeBrIf:
targetIndex, n, err := leb128.LoadUint32(c.body[c.pc+1:])
if err != nil {
return fmt.Errorf("read the target for br_if: %w", err)
}
c.pc += n
if c.unreachableState.on {
// If it is currently in unreachable, br-if is no-op.
break operatorSwitch
}
targetFrame := c.controlFrames.get(int(targetIndex))
targetFrame.ensureContinuation()
drop := c.getFrameDropRange(targetFrame, false)
target := targetFrame.asLabel()
c.result.LabelCallers[target]++
continuationLabel := NewLabel(LabelKindHeader, c.nextFrameID())
c.result.LabelCallers[continuationLabel]++
c.emit(NewOperationBrIf(target, continuationLabel, drop))
// Start emitting else block operations.
c.emit(NewOperationLabel(continuationLabel))
case wasm.OpcodeBrTable:
c.br.Reset(c.body[c.pc+1:])
r := c.br
numTargets, n, err := leb128.DecodeUint32(r)
if err != nil {
return fmt.Errorf("error reading number of targets in br_table: %w", err)
}
c.pc += n
if c.unreachableState.on {
// If it is currently in unreachable, br_table is no-op.
// But before proceeding to the next instruction, we must advance the pc
// according to the number of br_table targets.
for i := uint32(0); i <= numTargets; i++ { // inclusive as we also need to read the index of default target.
_, n, err := leb128.DecodeUint32(r)
if err != nil {
return fmt.Errorf("error reading target %d in br_table: %w", i, err)
}
c.pc += n
}
break operatorSwitch
}
// Read the branch targets.
s := numTargets * 2
targetLabels := make([]uint64, 2+s) // (label, InclusiveRange) * (default+numTargets)
for i := uint32(0); i < s; i += 2 {
l, n, err := leb128.DecodeUint32(r)
if err != nil {
return fmt.Errorf("error reading target %d in br_table: %w", i, err)
}
c.pc += n
targetFrame := c.controlFrames.get(int(l))
targetFrame.ensureContinuation()
drop := c.getFrameDropRange(targetFrame, false)
targetLabel := targetFrame.asLabel()
targetLabels[i] = uint64(targetLabel)
targetLabels[i+1] = drop.AsU64()
c.result.LabelCallers[targetLabel]++
}
// Prep default target control frame.
l, n, err := leb128.DecodeUint32(r)
if err != nil {
return fmt.Errorf("error reading default target of br_table: %w", err)
}
c.pc += n
defaultTargetFrame := c.controlFrames.get(int(l))
defaultTargetFrame.ensureContinuation()
defaultTargetDrop := c.getFrameDropRange(defaultTargetFrame, false)
defaultLabel := defaultTargetFrame.asLabel()
c.result.LabelCallers[defaultLabel]++
targetLabels[s] = uint64(defaultLabel)
targetLabels[s+1] = defaultTargetDrop.AsU64()
c.emit(NewOperationBrTable(targetLabels))
// br_table operation is stack-polymorphic, and mark the state as unreachable.
// That means subsequent instructions in the current control frame are "unreachable"
// and can be safely removed.
c.markUnreachable()
case wasm.OpcodeReturn:
functionFrame := c.controlFrames.functionFrame()
dropOp := NewOperationDrop(c.getFrameDropRange(functionFrame, false))
// Cleanup the stack and then jmp to function frame's continuation (meaning return).
c.emit(dropOp)
c.emit(NewOperationBr(functionFrame.asLabel()))
// Return operation is stack-polymorphic, and mark the state as unreachable.
// That means subsequent instructions in the current control frame are "unreachable"
// and can be safely removed.
c.markUnreachable()
case wasm.OpcodeCall:
c.emit(
NewOperationCall(index),
)
case wasm.OpcodeCallIndirect:
typeIndex := index
tableIndex, n, err := leb128.LoadUint32(c.body[c.pc+1:])
if err != nil {
return fmt.Errorf("read target for br_table: %w", err)
}
c.pc += n
c.emit(
NewOperationCallIndirect(typeIndex, tableIndex),
)
case wasm.OpcodeDrop:
r := InclusiveRange{Start: 0, End: 0}
if peekValueType == UnsignedTypeV128 {
// InclusiveRange is the range in uint64 representation, so dropping a vector value on top
// should be translated as drop [0..1] inclusively.
r.End++
}
c.emit(NewOperationDrop(r))
case wasm.OpcodeSelect:
// If it is on the unreachable state, ignore the instruction.
if c.unreachableState.on {
break operatorSwitch
}
isTargetVector := c.stackPeek() == UnsignedTypeV128
c.emit(
NewOperationSelect(isTargetVector),
)
case wasm.OpcodeTypedSelect:
// Skips two bytes: vector size fixed to 1, and the value type for select.
c.pc += 2
// If it is on the unreachable state, ignore the instruction.
if c.unreachableState.on {
break operatorSwitch
}
// Typed select is semantically equivalent to select at runtime.
isTargetVector := c.stackPeek() == UnsignedTypeV128
c.emit(
NewOperationSelect(isTargetVector),
)
case wasm.OpcodeLocalGet:
depth := c.localDepth(index)
if isVector := c.localType(index) == wasm.ValueTypeV128; !isVector {
c.emit(
// -1 because we already manipulated the stack before
// called localDepth ^^.
NewOperationPick(depth-1, isVector),
)
} else {
c.emit(
// -2 because we already manipulated the stack before
// called localDepth ^^.
NewOperationPick(depth-2, isVector),
)
}
case wasm.OpcodeLocalSet:
depth := c.localDepth(index)
isVector := c.localType(index) == wasm.ValueTypeV128
if isVector {
c.emit(
// +2 because we already popped the operands for this operation from the c.stack before
// called localDepth ^^,
NewOperationSet(depth+2, isVector),
)
} else {
c.emit(
// +1 because we already popped the operands for this operation from the c.stack before
// called localDepth ^^,
NewOperationSet(depth+1, isVector),
)
}
case wasm.OpcodeLocalTee:
depth := c.localDepth(index)
isVector := c.localType(index) == wasm.ValueTypeV128
if isVector {
c.emit(NewOperationPick(1, isVector))
c.emit(NewOperationSet(depth+2, isVector))
} else {
c.emit(
NewOperationPick(0, isVector))
c.emit(NewOperationSet(depth+1, isVector))
}
case wasm.OpcodeGlobalGet:
c.emit(
NewOperationGlobalGet(index),
)
case wasm.OpcodeGlobalSet:
c.emit(
NewOperationGlobalSet(index),
)
case wasm.OpcodeI32Load:
imm, err := c.readMemoryArg(wasm.OpcodeI32LoadName)
if err != nil {
return err
}
c.emit(NewOperationLoad(UnsignedTypeI32, imm))
case wasm.OpcodeI64Load:
imm, err := c.readMemoryArg(wasm.OpcodeI64LoadName)
if err != nil {
return err
}
c.emit(NewOperationLoad(UnsignedTypeI64, imm))
case wasm.OpcodeF32Load:
imm, err := c.readMemoryArg(wasm.OpcodeF32LoadName)
if err != nil {
return err
}
c.emit(NewOperationLoad(UnsignedTypeF32, imm))
case wasm.OpcodeF64Load:
imm, err := c.readMemoryArg(wasm.OpcodeF64LoadName)
if err != nil {
return err
}
c.emit(NewOperationLoad(UnsignedTypeF64, imm))
case wasm.OpcodeI32Load8S:
imm, err := c.readMemoryArg(wasm.OpcodeI32Load8SName)
if err != nil {
return err
}
c.emit(NewOperationLoad8(SignedInt32, imm))
case wasm.OpcodeI32Load8U:
imm, err := c.readMemoryArg(wasm.OpcodeI32Load8UName)
if err != nil {
return err
}
c.emit(NewOperationLoad8(SignedUint32, imm))
case wasm.OpcodeI32Load16S:
imm, err := c.readMemoryArg(wasm.OpcodeI32Load16SName)
if err != nil {
return err
}
c.emit(NewOperationLoad16(SignedInt32, imm))
case wasm.OpcodeI32Load16U:
imm, err := c.readMemoryArg(wasm.OpcodeI32Load16UName)
if err != nil {
return err
}
c.emit(NewOperationLoad16(SignedUint32, imm))
case wasm.OpcodeI64Load8S:
imm, err := c.readMemoryArg(wasm.OpcodeI64Load8SName)
if err != nil {
return err
}
c.emit(NewOperationLoad8(SignedInt64, imm))
case wasm.OpcodeI64Load8U:
imm, err := c.readMemoryArg(wasm.OpcodeI64Load8UName)
if err != nil {
return err
}
c.emit(NewOperationLoad8(SignedUint64, imm))
case wasm.OpcodeI64Load16S:
imm, err := c.readMemoryArg(wasm.OpcodeI64Load16SName)
if err != nil {
return err
}
c.emit(NewOperationLoad16(SignedInt64, imm))
case wasm.OpcodeI64Load16U:
imm, err := c.readMemoryArg(wasm.OpcodeI64Load16UName)
if err != nil {
return err
}
c.emit(NewOperationLoad16(SignedUint64, imm))
case wasm.OpcodeI64Load32S:
imm, err := c.readMemoryArg(wasm.OpcodeI64Load32SName)
if err != nil {
return err
}
c.emit(NewOperationLoad32(true, imm))
case wasm.OpcodeI64Load32U:
imm, err := c.readMemoryArg(wasm.OpcodeI64Load32UName)
if err != nil {
return err
}
c.emit(NewOperationLoad32(false, imm))
case wasm.OpcodeI32Store:
imm, err := c.readMemoryArg(wasm.OpcodeI32StoreName)
if err != nil {
return err
}
c.emit(
NewOperationStore(UnsignedTypeI32, imm),
)
case wasm.OpcodeI64Store:
imm, err := c.readMemoryArg(wasm.OpcodeI64StoreName)
if err != nil {
return err
}
c.emit(
NewOperationStore(UnsignedTypeI64, imm),
)
case wasm.OpcodeF32Store:
imm, err := c.readMemoryArg(wasm.OpcodeF32StoreName)
if err != nil {
return err
}
c.emit(
NewOperationStore(UnsignedTypeF32, imm),
)
case wasm.OpcodeF64Store:
imm, err := c.readMemoryArg(wasm.OpcodeF64StoreName)
if err != nil {
return err
}