BpConstants.v3

// Copyright 2020 Ben L. Titzer. All rights reserved.
// See LICENSE for details of Apache 2.0 license.

// Section codes.
enum BpSection(code: byte) {
	Unknown(0),
	Type(1),
	Import(2),
	Function(3),
	Table(4),
	Memory(5),
	Tag(13),	// ext:exception-handling
	Global(6),
	Export(7),
	Start(8),
	Element(9),
	DataCount(12),
	Code(10),
	Data(11),
}
// Import/export kind codes.
enum BpImportExportKind(code: byte) {
	Function(0),
	Table(1),
	Memory(2),
	Global(3),
	Tag(4),
	HeapType(5)
}
// Type constructor codes.
enum BpTypeCode(code: byte, val: i7) {
	I32		(0x7F, -1),
	I64		(0x7E, -2),
	F32		(0x7D, -3),
	F64		(0x7C, -4),
	V128		(0x7B, -5),
	I8		(0x78, -8),
	I16		(0x77, -9),
	NOCONT		(0x75, -11), //
	NULLFUNCREF	(0x73, -13), //
	NULLEXTERNREF	(0x72, -14), //
	NULLREF		(0x71, -15), //
	FUNCREF		(0x70, -16), //
	EXTERNREF	(0x6F, -17), //
	ANYREF		(0x6E, -18), //
	EQREF		(0x6D, -19), //
	I31REF		(0x6C, -20), //
	STRUCTREF	(0x6B, -21), //
	ARRAYREF	(0x6A, -22), //
	EXNREF		(0x69, -23), //
	CONTREF		(0x68, -24), //
	REF		(0x64, -28), //
	REF_NULL	(0x63, -29), //
	EmptyBlock	(0x40, -64) // XXX: move?
}
// Heap type codes.
enum BpHeapTypeCode(code: byte, val: i7) {
	FUNC		(0x70, -16), // -0x10
	EXTERN		(0x6F, -17), // -0x11
	ANY		(0x6E, -18), // -0x12
	EQ		(0x6D, -19), // -0x13
	I31		(0x6C, -20), // -0x14
	NOCONT		(0x75, -11), // -0x0b
	NOFUNC		(0x73, -13), // -0x0d
	NOEXTERN	(0x72, -14), // -0x0e
	STRUCT		(0x6B, -21), // -0x15
	ARRAY		(0x6A, -22), // -0x16
	EXN		(0x69, -23), // -0x17
	CONTREF		(0x68, -24),	// -0x18
	NONE		(0x71, -15)  // -0x0f
}
// Memory flag masks.
enum BpMemoryFlag(mask: byte) {
	HasMax(0x01),
	Shared(0x02),
	Is64(0x04),
	HasPageSize(0x08),
}
// Table flag masks.
enum BpTableFlag(mask: byte) {
	HasMax(0x01),
}
// Global flag masks.
enum BpGlobalFlag(mask: byte) {
	Mutable(0x01)
}
// Heap type declaration codes.
enum BpDefTypeCode(code: byte, val: i7) {
	Function	(0x60, -32),
	Struct		(0x5F, -33),
	Array		(0x5E, -34),
	Continuation	(0x5D, -35),
	SUB		(0x50, -48),
	SUB_FINAL	(0x4F, -49),
	REC		(0x4E, -50)
}
// Catch kinds
enum BpCatchKind(code: u8) {
	CATCH(0x00),
	CATCH_REF(0x01),
	CATCH_ALL(0x02),
	CATCH_ALL_REF(0x03)
}
// Catch codes
type BpCatchCode {
	case Catch(tag_index: u31, label: u31);
	case CatchRef(tag_index: u31, label: u31);
	case CatchAll(label: u31);
	case CatchAllRef(label: u31);
}

// Utilities associated with binary sections and other quantities.
component BpConstants {
	def WASM_MAGIC = 0x6d736100u;
	def WASM_VERSION = 0x01u;
	def WASM_PAGE_SIZE = 65536u31;
	def log2_WASM_PAGE_SIZE = 16u5;
	def MEMARG_INDEX_FLAG = byte.view(0x40u);
	def valid_section = Array<bool>.new(256);
	def enum_section = Array<BpSection>.new(256);
	new() {
		for (s in BpSection) {
			valid_section[s.code] = true;
			enum_section[s.code] = s;
		}
	}
	def typeCodeHasIndex(code: int) -> bool {
		match (code) {
			BpTypeCode.REF.val,
			BpTypeCode.REF_NULL.val => return true;
			_ => return false;
		}
	}
	def renderSectionName(buf: StringBuilder, b: byte) -> StringBuilder {
		var s = "unknown";
		match (b) {
			BpSection.Type.code => s = "type";
			BpSection.Import.code => s = "import";
			BpSection.Function.code => s = "function";
			BpSection.Table.code => s = "table";
			BpSection.Memory.code => s = "memory";
			BpSection.Tag.code => s = "tag";
			BpSection.Global.code => s = "global";
			BpSection.Export.code => s = "export";
			BpSection.Start.code => s = "start";
			BpSection.Element.code => s = "element";
			BpSection.Code.code => s = "code";
			BpSection.Data.code => s = "data";
			BpSection.DataCount.code => s = "data count";
		}
		return buf.puts(s);
	}
	def renderImportKind(buf: StringBuilder, b: byte) -> StringBuilder {
		var s = "unknown";
		match (b) {
			BpImportExportKind.Function.code => s = "function";
			BpImportExportKind.Table.code => s = "table";
			BpImportExportKind.Memory.code => s = "memory";
			BpImportExportKind.Global.code => s = "global";
			BpImportExportKind.Tag.code => s = "tag";
			BpImportExportKind.HeapType.code => s = "type";
		}
		return buf.puts(s);
	}
	def renderTypeCode(buf: StringBuilder, val: int) -> StringBuilder {
		var str: string;
		match (val) {
			BpTypeCode.I32.val => str = "i32";
			BpTypeCode.I64.val => str = "i64";
			BpTypeCode.F32.val => str = "f32";
			BpTypeCode.F64.val => str = "f64";
			BpTypeCode.V128.val => str = "v128";
			BpTypeCode.I8.val => str = "i8";
			BpTypeCode.I16.val => str = "i16";
			BpTypeCode.NOCONT.val => str = "nocont";
			BpTypeCode.CONTREF.val => str = "ref null cont";
			BpTypeCode.FUNCREF.val => str = "funcref";
			BpTypeCode.EXTERNREF.val => str = "externref";
			BpTypeCode.ANYREF.val => str = "anyref";
			BpTypeCode.EQREF.val => str = "eqref";
			BpTypeCode.EmptyBlock.val => str = "empty block type";
			BpTypeCode.REF_NULL.val => str = "ref null <T>";
			BpTypeCode.REF.val => str = "ref <T>";
			BpTypeCode.I31REF.val => str = "i31ref";
			BpTypeCode.STRUCTREF.val => str = "structref";
			BpTypeCode.ARRAYREF.val => str = "arrayref";
			BpTypeCode.NULLREF.val => str = "ref null none";
			BpTypeCode.NULLEXTERNREF.val => str = "ref null noextern";
			BpTypeCode.NULLFUNCREF.val => str = "ref null nofunc";
		}
		if (str == null) buf.put1("<unknown type code: %d>", val);
		else buf.puts(str);
		return buf;
	}
	def renderDefTypeCode(buf: StringBuilder, b: byte) -> StringBuilder {
		var s = "unknown";
		match (b) {
			BpDefTypeCode.Function.code => s = "func";
			BpDefTypeCode.Struct.code => s = "struct";
			BpDefTypeCode.Array.code => s = "array";
			BpDefTypeCode.REC.code => s = "rec";
			BpDefTypeCode.SUB.code => s = "sub";
			BpDefTypeCode.Continuation.code => s = "cont";
		}
		return buf.puts(s);
	}
	def renderNone(buf: StringBuilder, b: byte) -> StringBuilder {
		return buf;
	}
	def renderMutability(buf: StringBuilder, b: byte) -> StringBuilder {
		if ((b & BpGlobalFlag.Mutable.mask) != 0) buf.puts("mutable");
		return buf;
	}
	def renderTableFlags(buf: StringBuilder, b: byte) -> StringBuilder {
		if ((b & BpMemoryFlag.HasMax.mask) != 0) buf.puts("has_max");
		return buf;
	}
	def renderMemoryFlags(buf: StringBuilder, b: byte) -> StringBuilder {
		if ((b & BpMemoryFlag.HasMax.mask) != 0) buf.puts("has_max");
		if ((b & BpMemoryFlag.Shared.mask) != 0) buf.puts(" shared");
		if ((b & BpMemoryFlag.Is64.mask) != 0) buf.puts(" is64");
		if ((b & BpMemoryFlag.HasPageSize.mask) != 0) buf.puts(" has_page_size");
		return buf;
	}
	def renderAttribute(buf: StringBuilder, b: byte) -> StringBuilder {
		if ((b & 1) == 0) buf.puts("exception");
		return buf;
	}
}