[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, 170 insertions, 0 deletions

diff --git a/vendor/github.com/tetratelabs/wazero/internal/engine/wazevo/backend/abi.go b/vendor/github.com/tetratelabs/wazero/internal/engine/wazevo/backend/abi.go
new file mode 100644
index 000000000..cf91c6b7a
--- /dev/null
+++ b/vendor/github.com/tetratelabs/wazero/internal/engine/wazevo/backend/abi.go
@@ -0,0 +1,170 @@
+package backend
+
+import (
+	"fmt"
+
+	"github.com/tetratelabs/wazero/internal/engine/wazevo/backend/regalloc"
+	"github.com/tetratelabs/wazero/internal/engine/wazevo/ssa"
+)
+
+type (
+	// FunctionABI represents the ABI information for a function which corresponds to a ssa.Signature.
+	FunctionABI struct {
+		Initialized bool
+
+		Args, Rets                 []ABIArg
+		ArgStackSize, RetStackSize int64
+
+		ArgIntRealRegs   byte
+		ArgFloatRealRegs byte
+		RetIntRealRegs   byte
+		RetFloatRealRegs byte
+	}
+
+	// ABIArg represents either argument or return value's location.
+	ABIArg struct {
+		// Index is the index of the argument.
+		Index int
+		// Kind is the kind of the argument.
+		Kind ABIArgKind
+		// Reg is valid if Kind == ABIArgKindReg.
+		// This VReg must be based on RealReg.
+		Reg regalloc.VReg
+		// Offset is valid if Kind == ABIArgKindStack.
+		// This is the offset from the beginning of either arg or ret stack slot.
+		Offset int64
+		// Type is the type of the argument.
+		Type ssa.Type
+	}
+
+	// ABIArgKind is the kind of ABI argument.
+	ABIArgKind byte
+)
+
+const (
+	// ABIArgKindReg represents an argument passed in a register.
+	ABIArgKindReg = iota
+	// ABIArgKindStack represents an argument passed in the stack.
+	ABIArgKindStack
+)
+
+// String implements fmt.Stringer.
+func (a *ABIArg) String() string {
+	return fmt.Sprintf("args[%d]: %s", a.Index, a.Kind)
+}
+
+// String implements fmt.Stringer.
+func (a ABIArgKind) String() string {
+	switch a {
+	case ABIArgKindReg:
+		return "reg"
+	case ABIArgKindStack:
+		return "stack"
+	default:
+		panic("BUG")
+	}
+}
+
+// Init initializes the abiImpl for the given signature.
+func (a *FunctionABI) Init(sig *ssa.Signature, argResultInts, argResultFloats []regalloc.RealReg) {
+	if len(a.Rets) < len(sig.Results) {
+		a.Rets = make([]ABIArg, len(sig.Results))
+	}
+	a.Rets = a.Rets[:len(sig.Results)]
+	a.RetStackSize = a.setABIArgs(a.Rets, sig.Results, argResultInts, argResultFloats)
+	if argsNum := len(sig.Params); len(a.Args) < argsNum {
+		a.Args = make([]ABIArg, argsNum)
+	}
+	a.Args = a.Args[:len(sig.Params)]
+	a.ArgStackSize = a.setABIArgs(a.Args, sig.Params, argResultInts, argResultFloats)
+
+	// Gather the real registers usages in arg/return.
+	a.ArgIntRealRegs, a.ArgFloatRealRegs = 0, 0
+	a.RetIntRealRegs, a.RetFloatRealRegs = 0, 0
+	for i := range a.Rets {
+		r := &a.Rets[i]
+		if r.Kind == ABIArgKindReg {
+			if r.Type.IsInt() {
+				a.RetIntRealRegs++
+			} else {
+				a.RetFloatRealRegs++
+			}
+		}
+	}
+	for i := range a.Args {
+		arg := &a.Args[i]
+		if arg.Kind == ABIArgKindReg {
+			if arg.Type.IsInt() {
+				a.ArgIntRealRegs++
+			} else {
+				a.ArgFloatRealRegs++
+			}
+		}
+	}
+
+	a.Initialized = true
+}
+
+// setABIArgs sets the ABI arguments in the given slice. This assumes that len(s) >= len(types)
+// where if len(s) > len(types), the last elements of s is for the multi-return slot.
+func (a *FunctionABI) setABIArgs(s []ABIArg, types []ssa.Type, ints, floats []regalloc.RealReg) (stackSize int64) {
+	il, fl := len(ints), len(floats)
+
+	var stackOffset int64
+	intParamIndex, floatParamIndex := 0, 0
+	for i, typ := range types {
+		arg := &s[i]
+		arg.Index = i
+		arg.Type = typ
+		if typ.IsInt() {
+			if intParamIndex >= il {
+				arg.Kind = ABIArgKindStack
+				const slotSize = 8 // Align 8 bytes.
+				arg.Offset = stackOffset
+				stackOffset += slotSize
+			} else {
+				arg.Kind = ABIArgKindReg
+				arg.Reg = regalloc.FromRealReg(ints[intParamIndex], regalloc.RegTypeInt)
+				intParamIndex++
+			}
+		} else {
+			if floatParamIndex >= fl {
+				arg.Kind = ABIArgKindStack
+				slotSize := int64(8)   // Align at least 8 bytes.
+				if typ.Bits() == 128 { // Vector.
+					slotSize = 16
+				}
+				arg.Offset = stackOffset
+				stackOffset += slotSize
+			} else {
+				arg.Kind = ABIArgKindReg
+				arg.Reg = regalloc.FromRealReg(floats[floatParamIndex], regalloc.RegTypeFloat)
+				floatParamIndex++
+			}
+		}
+	}
+	return stackOffset
+}
+
+func (a *FunctionABI) AlignedArgResultStackSlotSize() uint32 {
+	stackSlotSize := a.RetStackSize + a.ArgStackSize
+	// Align stackSlotSize to 16 bytes.
+	stackSlotSize = (stackSlotSize + 15) &^ 15
+	// Check overflow 32-bit.
+	if stackSlotSize > 0xFFFFFFFF {
+		panic("ABI stack slot size overflow")
+	}
+	return uint32(stackSlotSize)
+}
+
+func (a *FunctionABI) ABIInfoAsUint64() uint64 {
+	return uint64(a.ArgIntRealRegs)<<56 |
+		uint64(a.ArgFloatRealRegs)<<48 |
+		uint64(a.RetIntRealRegs)<<40 |
+		uint64(a.RetFloatRealRegs)<<32 |
+		uint64(a.AlignedArgResultStackSlotSize())
+}
+
+func ABIInfoFromUint64(info uint64) (argIntRealRegs, argFloatRealRegs, retIntRealRegs, retFloatRealRegs byte, stackSlotSize uint32) {
+	return byte(info >> 56), byte(info >> 48), byte(info >> 40), byte(info >> 32), uint32(info)
+}