[experiment] add alternative wasm sqlite3 implementation available via build-tag (#2863)

This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).

1 files changed, 417 insertions, 0 deletions

diff --git a/vendor/github.com/tetratelabs/wazero/internal/engine/wazevo/backend/compiler.go b/vendor/github.com/tetratelabs/wazero/internal/engine/wazevo/backend/compiler.go
new file mode 100644
index 000000000..59bbfe02d
--- /dev/null
+++ b/vendor/github.com/tetratelabs/wazero/internal/engine/wazevo/backend/compiler.go
@@ -0,0 +1,417 @@
+package backend
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/tetratelabs/wazero/internal/engine/wazevo/backend/regalloc"
+	"github.com/tetratelabs/wazero/internal/engine/wazevo/ssa"
+	"github.com/tetratelabs/wazero/internal/engine/wazevo/wazevoapi"
+)
+
+// NewCompiler returns a new Compiler that can generate a machine code.
+func NewCompiler(ctx context.Context, mach Machine, builder ssa.Builder) Compiler {
+	return newCompiler(ctx, mach, builder)
+}
+
+func newCompiler(_ context.Context, mach Machine, builder ssa.Builder) *compiler {
+	argResultInts, argResultFloats := mach.ArgsResultsRegs()
+	c := &compiler{
+		mach: mach, ssaBuilder: builder,
+		nextVRegID:      regalloc.VRegIDNonReservedBegin,
+		argResultInts:   argResultInts,
+		argResultFloats: argResultFloats,
+	}
+	mach.SetCompiler(c)
+	return c
+}
+
+// Compiler is the backend of wazevo which takes ssa.Builder and Machine,
+// use the information there to emit the final machine code.
+type Compiler interface {
+	// SSABuilder returns the ssa.Builder used by this compiler.
+	SSABuilder() ssa.Builder
+
+	// Compile executes the following steps:
+	// 	1. Lower()
+	// 	2. RegAlloc()
+	// 	3. Finalize()
+	// 	4. Encode()
+	//
+	// Each step can be called individually for testing purpose, therefore they are exposed in this interface too.
+	//
+	// The returned byte slices are the machine code and the relocation information for the machine code.
+	// The caller is responsible for copying them immediately since the compiler may reuse the buffer.
+	Compile(ctx context.Context) (_ []byte, _ []RelocationInfo, _ error)
+
+	// Lower lowers the given ssa.Instruction to the machine-specific instructions.
+	Lower()
+
+	// RegAlloc performs the register allocation after Lower is called.
+	RegAlloc()
+
+	// Finalize performs the finalization of the compilation, including machine code emission.
+	// This must be called after RegAlloc.
+	Finalize(ctx context.Context) error
+
+	// Buf returns the buffer of the encoded machine code. This is only used for testing purpose.
+	Buf() []byte
+
+	BufPtr() *[]byte
+
+	// Format returns the debug string of the current state of the compiler.
+	Format() string
+
+	// Init initializes the internal state of the compiler for the next compilation.
+	Init()
+
+	// AllocateVReg allocates a new virtual register of the given type.
+	AllocateVReg(typ ssa.Type) regalloc.VReg
+
+	// ValueDefinition returns the definition of the given value.
+	ValueDefinition(ssa.Value) *SSAValueDefinition
+
+	// VRegOf returns the virtual register of the given ssa.Value.
+	VRegOf(value ssa.Value) regalloc.VReg
+
+	// TypeOf returns the ssa.Type of the given virtual register.
+	TypeOf(regalloc.VReg) ssa.Type
+
+	// MatchInstr returns true if the given definition is from an instruction with the given opcode, the current group ID,
+	// and a refcount of 1. That means, the instruction can be merged/swapped within the current instruction group.
+	MatchInstr(def *SSAValueDefinition, opcode ssa.Opcode) bool
+
+	// MatchInstrOneOf is the same as MatchInstr but for multiple opcodes. If it matches one of ssa.Opcode,
+	// this returns the opcode. Otherwise, this returns ssa.OpcodeInvalid.
+	//
+	// Note: caller should be careful to avoid excessive allocation on opcodes slice.
+	MatchInstrOneOf(def *SSAValueDefinition, opcodes []ssa.Opcode) ssa.Opcode
+
+	// AddRelocationInfo appends the relocation information for the function reference at the current buffer offset.
+	AddRelocationInfo(funcRef ssa.FuncRef)
+
+	// AddSourceOffsetInfo appends the source offset information for the given offset.
+	AddSourceOffsetInfo(executableOffset int64, sourceOffset ssa.SourceOffset)
+
+	// SourceOffsetInfo returns the source offset information for the current buffer offset.
+	SourceOffsetInfo() []SourceOffsetInfo
+
+	// EmitByte appends a byte to the buffer. Used during the code emission.
+	EmitByte(b byte)
+
+	// Emit4Bytes appends 4 bytes to the buffer. Used during the code emission.
+	Emit4Bytes(b uint32)
+
+	// Emit8Bytes appends 8 bytes to the buffer. Used during the code emission.
+	Emit8Bytes(b uint64)
+
+	// GetFunctionABI returns the ABI information for the given signature.
+	GetFunctionABI(sig *ssa.Signature) *FunctionABI
+}
+
+// RelocationInfo represents the relocation information for a call instruction.
+type RelocationInfo struct {
+	// Offset represents the offset from the beginning of the machine code of either a function or the entire module.
+	Offset int64
+	// Target is the target function of the call instruction.
+	FuncRef ssa.FuncRef
+}
+
+// compiler implements Compiler.
+type compiler struct {
+	mach       Machine
+	currentGID ssa.InstructionGroupID
+	ssaBuilder ssa.Builder
+	// nextVRegID is the next virtual register ID to be allocated.
+	nextVRegID regalloc.VRegID
+	// ssaValueToVRegs maps ssa.ValueID to regalloc.VReg.
+	ssaValueToVRegs [] /* VRegID to */ regalloc.VReg
+	// ssaValueDefinitions maps ssa.ValueID to its definition.
+	ssaValueDefinitions []SSAValueDefinition
+	// ssaValueRefCounts is a cached list obtained by ssa.Builder.ValueRefCounts().
+	ssaValueRefCounts []int
+	// returnVRegs is the list of virtual registers that store the return values.
+	returnVRegs  []regalloc.VReg
+	varEdges     [][2]regalloc.VReg
+	varEdgeTypes []ssa.Type
+	constEdges   []struct {
+		cInst *ssa.Instruction
+		dst   regalloc.VReg
+	}
+	vRegSet         []bool
+	vRegIDs         []regalloc.VRegID
+	tempRegs        []regalloc.VReg
+	tmpVals         []ssa.Value
+	ssaTypeOfVRegID [] /* VRegID to */ ssa.Type
+	buf             []byte
+	relocations     []RelocationInfo
+	sourceOffsets   []SourceOffsetInfo
+	// abis maps ssa.SignatureID to the ABI implementation.
+	abis                           []FunctionABI
+	argResultInts, argResultFloats []regalloc.RealReg
+}
+
+// SourceOffsetInfo is a data to associate the source offset with the executable offset.
+type SourceOffsetInfo struct {
+	// SourceOffset is the source offset in the original source code.
+	SourceOffset ssa.SourceOffset
+	// ExecutableOffset is the offset in the compiled executable.
+	ExecutableOffset int64
+}
+
+// Compile implements Compiler.Compile.
+func (c *compiler) Compile(ctx context.Context) ([]byte, []RelocationInfo, error) {
+	c.Lower()
+	if wazevoapi.PrintSSAToBackendIRLowering && wazevoapi.PrintEnabledIndex(ctx) {
+		fmt.Printf("[[[after lowering for %s ]]]%s\n", wazevoapi.GetCurrentFunctionName(ctx), c.Format())
+	}
+	if wazevoapi.DeterministicCompilationVerifierEnabled {
+		wazevoapi.VerifyOrSetDeterministicCompilationContextValue(ctx, "After lowering to ISA specific IR", c.Format())
+	}
+	c.RegAlloc()
+	if wazevoapi.PrintRegisterAllocated && wazevoapi.PrintEnabledIndex(ctx) {
+		fmt.Printf("[[[after regalloc for %s]]]%s\n", wazevoapi.GetCurrentFunctionName(ctx), c.Format())
+	}
+	if wazevoapi.DeterministicCompilationVerifierEnabled {
+		wazevoapi.VerifyOrSetDeterministicCompilationContextValue(ctx, "After Register Allocation", c.Format())
+	}
+	if err := c.Finalize(ctx); err != nil {
+		return nil, nil, err
+	}
+	if wazevoapi.PrintFinalizedMachineCode && wazevoapi.PrintEnabledIndex(ctx) {
+		fmt.Printf("[[[after finalize for %s]]]%s\n", wazevoapi.GetCurrentFunctionName(ctx), c.Format())
+	}
+	if wazevoapi.DeterministicCompilationVerifierEnabled {
+		wazevoapi.VerifyOrSetDeterministicCompilationContextValue(ctx, "After Finalization", c.Format())
+	}
+	return c.buf, c.relocations, nil
+}
+
+// RegAlloc implements Compiler.RegAlloc.
+func (c *compiler) RegAlloc() {
+	c.mach.RegAlloc()
+}
+
+// Finalize implements Compiler.Finalize.
+func (c *compiler) Finalize(ctx context.Context) error {
+	c.mach.PostRegAlloc()
+	return c.mach.Encode(ctx)
+}
+
+// setCurrentGroupID sets the current instruction group ID.
+func (c *compiler) setCurrentGroupID(gid ssa.InstructionGroupID) {
+	c.currentGID = gid
+}
+
+// assignVirtualRegisters assigns a virtual register to each ssa.ValueID Valid in the ssa.Builder.
+func (c *compiler) assignVirtualRegisters() {
+	builder := c.ssaBuilder
+	refCounts := builder.ValueRefCounts()
+	c.ssaValueRefCounts = refCounts
+
+	need := len(refCounts)
+	if need >= len(c.ssaValueToVRegs) {
+		c.ssaValueToVRegs = append(c.ssaValueToVRegs, make([]regalloc.VReg, need+1)...)
+	}
+	if need >= len(c.ssaValueDefinitions) {
+		c.ssaValueDefinitions = append(c.ssaValueDefinitions, make([]SSAValueDefinition, need+1)...)
+	}
+
+	for blk := builder.BlockIteratorReversePostOrderBegin(); blk != nil; blk = builder.BlockIteratorReversePostOrderNext() {
+		// First we assign a virtual register to each parameter.
+		for i := 0; i < blk.Params(); i++ {
+			p := blk.Param(i)
+			pid := p.ID()
+			typ := p.Type()
+			vreg := c.AllocateVReg(typ)
+			c.ssaValueToVRegs[pid] = vreg
+			c.ssaValueDefinitions[pid] = SSAValueDefinition{BlockParamValue: p, BlkParamVReg: vreg}
+			c.ssaTypeOfVRegID[vreg.ID()] = p.Type()
+		}
+
+		// Assigns each value to a virtual register produced by instructions.
+		for cur := blk.Root(); cur != nil; cur = cur.Next() {
+			r, rs := cur.Returns()
+			var N int
+			if r.Valid() {
+				id := r.ID()
+				ssaTyp := r.Type()
+				typ := r.Type()
+				vReg := c.AllocateVReg(typ)
+				c.ssaValueToVRegs[id] = vReg
+				c.ssaValueDefinitions[id] = SSAValueDefinition{
+					Instr:    cur,
+					N:        0,
+					RefCount: refCounts[id],
+				}
+				c.ssaTypeOfVRegID[vReg.ID()] = ssaTyp
+				N++
+			}
+			for _, r := range rs {
+				id := r.ID()
+				ssaTyp := r.Type()
+				vReg := c.AllocateVReg(ssaTyp)
+				c.ssaValueToVRegs[id] = vReg
+				c.ssaValueDefinitions[id] = SSAValueDefinition{
+					Instr:    cur,
+					N:        N,
+					RefCount: refCounts[id],
+				}
+				c.ssaTypeOfVRegID[vReg.ID()] = ssaTyp
+				N++
+			}
+		}
+	}
+
+	for i, retBlk := 0, builder.ReturnBlock(); i < retBlk.Params(); i++ {
+		typ := retBlk.Param(i).Type()
+		vReg := c.AllocateVReg(typ)
+		c.returnVRegs = append(c.returnVRegs, vReg)
+		c.ssaTypeOfVRegID[vReg.ID()] = typ
+	}
+}
+
+// AllocateVReg implements Compiler.AllocateVReg.
+func (c *compiler) AllocateVReg(typ ssa.Type) regalloc.VReg {
+	regType := regalloc.RegTypeOf(typ)
+	r := regalloc.VReg(c.nextVRegID).SetRegType(regType)
+
+	id := r.ID()
+	if int(id) >= len(c.ssaTypeOfVRegID) {
+		c.ssaTypeOfVRegID = append(c.ssaTypeOfVRegID, make([]ssa.Type, id+1)...)
+	}
+	c.ssaTypeOfVRegID[id] = typ
+	c.nextVRegID++
+	return r
+}
+
+// Init implements Compiler.Init.
+func (c *compiler) Init() {
+	c.currentGID = 0
+	c.nextVRegID = regalloc.VRegIDNonReservedBegin
+	c.returnVRegs = c.returnVRegs[:0]
+	c.mach.Reset()
+	c.varEdges = c.varEdges[:0]
+	c.constEdges = c.constEdges[:0]
+	c.buf = c.buf[:0]
+	c.sourceOffsets = c.sourceOffsets[:0]
+	c.relocations = c.relocations[:0]
+}
+
+// ValueDefinition implements Compiler.ValueDefinition.
+func (c *compiler) ValueDefinition(value ssa.Value) *SSAValueDefinition {
+	return &c.ssaValueDefinitions[value.ID()]
+}
+
+// VRegOf implements Compiler.VRegOf.
+func (c *compiler) VRegOf(value ssa.Value) regalloc.VReg {
+	return c.ssaValueToVRegs[value.ID()]
+}
+
+// Format implements Compiler.Format.
+func (c *compiler) Format() string {
+	return c.mach.Format()
+}
+
+// TypeOf implements Compiler.Format.
+func (c *compiler) TypeOf(v regalloc.VReg) ssa.Type {
+	return c.ssaTypeOfVRegID[v.ID()]
+}
+
+// MatchInstr implements Compiler.MatchInstr.
+func (c *compiler) MatchInstr(def *SSAValueDefinition, opcode ssa.Opcode) bool {
+	instr := def.Instr
+	return def.IsFromInstr() &&
+		instr.Opcode() == opcode &&
+		instr.GroupID() == c.currentGID &&
+		def.RefCount < 2
+}
+
+// MatchInstrOneOf implements Compiler.MatchInstrOneOf.
+func (c *compiler) MatchInstrOneOf(def *SSAValueDefinition, opcodes []ssa.Opcode) ssa.Opcode {
+	instr := def.Instr
+	if !def.IsFromInstr() {
+		return ssa.OpcodeInvalid
+	}
+
+	if instr.GroupID() != c.currentGID {
+		return ssa.OpcodeInvalid
+	}
+
+	if def.RefCount >= 2 {
+		return ssa.OpcodeInvalid
+	}
+
+	opcode := instr.Opcode()
+	for _, op := range opcodes {
+		if opcode == op {
+			return opcode
+		}
+	}
+	return ssa.OpcodeInvalid
+}
+
+// SSABuilder implements Compiler .SSABuilder.
+func (c *compiler) SSABuilder() ssa.Builder {
+	return c.ssaBuilder
+}
+
+// AddSourceOffsetInfo implements Compiler.AddSourceOffsetInfo.
+func (c *compiler) AddSourceOffsetInfo(executableOffset int64, sourceOffset ssa.SourceOffset) {
+	c.sourceOffsets = append(c.sourceOffsets, SourceOffsetInfo{
+		SourceOffset:     sourceOffset,
+		ExecutableOffset: executableOffset,
+	})
+}
+
+// SourceOffsetInfo implements Compiler.SourceOffsetInfo.
+func (c *compiler) SourceOffsetInfo() []SourceOffsetInfo {
+	return c.sourceOffsets
+}
+
+// AddRelocationInfo implements Compiler.AddRelocationInfo.
+func (c *compiler) AddRelocationInfo(funcRef ssa.FuncRef) {
+	c.relocations = append(c.relocations, RelocationInfo{
+		Offset:  int64(len(c.buf)),
+		FuncRef: funcRef,
+	})
+}
+
+// Emit8Bytes implements Compiler.Emit8Bytes.
+func (c *compiler) Emit8Bytes(b uint64) {
+	c.buf = append(c.buf, byte(b), byte(b>>8), byte(b>>16), byte(b>>24), byte(b>>32), byte(b>>40), byte(b>>48), byte(b>>56))
+}
+
+// Emit4Bytes implements Compiler.Emit4Bytes.
+func (c *compiler) Emit4Bytes(b uint32) {
+	c.buf = append(c.buf, byte(b), byte(b>>8), byte(b>>16), byte(b>>24))
+}
+
+// EmitByte implements Compiler.EmitByte.
+func (c *compiler) EmitByte(b byte) {
+	c.buf = append(c.buf, b)
+}
+
+// Buf implements Compiler.Buf.
+func (c *compiler) Buf() []byte {
+	return c.buf
+}
+
+// BufPtr implements Compiler.BufPtr.
+func (c *compiler) BufPtr() *[]byte {
+	return &c.buf
+}
+
+func (c *compiler) GetFunctionABI(sig *ssa.Signature) *FunctionABI {
+	if int(sig.ID) >= len(c.abis) {
+		c.abis = append(c.abis, make([]FunctionABI, int(sig.ID)+1)...)
+	}
+
+	abi := &c.abis[sig.ID]
+	if abi.Initialized {
+		return abi
+	}
+
+	abi.Init(sig, c.argResultInts, c.argResultFloats)
+	return abi
+}