diff options
| -rw-r--r-- | lib/std/wasm.zig | 14 | ||||
| -rw-r--r-- | src/codegen/wasm.zig | 28 | ||||
| -rw-r--r-- | src/link/Wasm.zig | 66 |
3 files changed, 93 insertions, 15 deletions
diff --git a/lib/std/wasm.zig b/lib/std/wasm.zig index aa087c89c9..c59117d65b 100644 --- a/lib/std/wasm.zig +++ b/lib/std/wasm.zig @@ -253,6 +253,20 @@ pub fn section(val: Section) u8 { return @enumToInt(val); } +/// The kind of the type when importing or exporting to/from the host environment +/// https://webassembly.github.io/spec/core/syntax/modules.html +pub const ExternalKind = enum(u8) { + function, + table, + memory, + global, +}; + +/// Returns the integer value of a given `ExternalKind` +pub fn kind(val: ExternalKind) u8 { + return @enumToInt(val); +} + // types pub const element_type: u8 = 0x70; pub const function_type: u8 = 0x60; diff --git a/src/codegen/wasm.zig b/src/codegen/wasm.zig index abc411b551..5be26de7cb 100644 --- a/src/codegen/wasm.zig +++ b/src/codegen/wasm.zig @@ -163,13 +163,18 @@ pub const Context = struct { try self.genFunctype(); const writer = self.code.writer(); - // Reserve space to write the size after generating the code as well as space for locals count - try self.code.resize(10); - // Write instructions // TODO: check for and handle death of instructions const tv = self.decl.typed_value.most_recent.typed_value; - const mod_fn = tv.val.castTag(.function).?.data; + const mod_fn = blk: { + if (tv.val.castTag(.function)) |func| break :blk func.data; + if (tv.val.castTag(.extern_fn)) |ext_fn| return; // don't need codegen for extern functions + return self.fail(self.decl.src(), "TODO: Wasm codegen for decl type '{s}'", .{tv.ty.tag()}); + }; + + // Reserve space to write the size after generating the code as well as space for locals count + try self.code.resize(10); + try self.genBody(mod_fn.body); // finally, write our local types at the 'offset' position @@ -239,9 +244,16 @@ pub const Context = struct { fn genCall(self: *Context, inst: *Inst.Call) InnerError!WValue { const func_inst = inst.func.castTag(.constant).?; - const func = func_inst.val.castTag(.function).?.data; - const target = func.owner_decl; - const target_ty = target.typed_value.most_recent.typed_value.ty; + const func_val = inst.func.value().?; + + const target = blk: { + if (func_val.castTag(.function)) |func| { + break :blk func.data.owner_decl; + } else if (func_val.castTag(.extern_fn)) |ext_fn| { + break :blk ext_fn.data; + } + return self.fail(inst.base.src, "Expected a function, but instead found type '{s}'", .{func_val.tag()}); + }; for (inst.args) |arg| { const arg_val = self.resolveInst(arg); @@ -495,7 +507,7 @@ pub const Context = struct { } fn genBr(self: *Context, br: *Inst.Br) InnerError!WValue { - // of operand has codegen bits we should break with a value + // if operand has codegen bits we should break with a value if (br.operand.ty.hasCodeGenBits()) { const operand = self.resolveInst(br.operand); try self.emitWValue(operand); diff --git a/src/link/Wasm.zig b/src/link/Wasm.zig index 547ab2a012..9660ff0a43 100644 --- a/src/link/Wasm.zig +++ b/src/link/Wasm.zig @@ -85,8 +85,6 @@ pub fn updateDecl(self: *Wasm, module: *Module, decl: *Module.Decl) !void { const typed_value = decl.typed_value.most_recent.typed_value; if (typed_value.ty.zigTypeTag() != .Fn) return error.TODOImplementNonFnDeclsForWasm; - if (typed_value.val.tag() == .extern_fn) - return error.TODOImplementExternFnDeclsForWasm; if (decl.fn_link.wasm) |*fn_data| { fn_data.functype.items.len = 0; @@ -184,17 +182,63 @@ pub fn flushModule(self: *Wasm, comp: *Compilation) !void { ); } + // Import section + { + // TODO: implement non-functions imports + const header_offset = try reserveVecSectionHeader(file); + const writer = file.writer(); + var count: u32 = 0; + for (self.funcs.items) |decl, typeidx| { + if (decl.typed_value.most_recent.typed_value.val.tag() != .extern_fn) { + continue; + } + + // TODO: can we set/save the module name somewhere? + // For now, emit "env" like LLVM does + const module_name = "env"; + try leb.writeULEB128(writer, @intCast(u32, module_name.len)); + try writer.writeAll(module_name); + + // wasm requires the length of the import name and doesn't require a null-termination + const decl_len = mem.len(decl.name); + try leb.writeULEB128(writer, @intCast(u32, decl_len)); + try writer.writeAll(decl.name[0..decl_len]); + + // emit kind and the function type + try writer.writeByte(wasm.kind(.function)); + try leb.writeULEB128(writer, @intCast(u32, typeidx)); + + count += 1; + } + + try writeVecSectionHeader( + file, + header_offset, + .import, + @intCast(u32, (try file.getPos()) - header_offset - header_size), + count, + ); + } + // Function section { const header_offset = try reserveVecSectionHeader(file); const writer = file.writer(); - for (self.funcs.items) |_, typeidx| try leb.writeULEB128(writer, @intCast(u32, typeidx)); + var count: u32 = 0; + for (self.funcs.items) |decl, typeidx| { + // Extern functions only have a type, so skip the function signature section + if (decl.typed_value.most_recent.typed_value.val.tag() != .function) { + continue; + } + try leb.writeULEB128(writer, @intCast(u32, typeidx)); + count += 1; + } try writeVecSectionHeader( file, header_offset, .function, @intCast(u32, (try file.getPos()) - header_offset - header_size), - @intCast(u32, self.funcs.items.len), + count, ); } @@ -214,7 +258,7 @@ pub fn flushModule(self: *Wasm, comp: *Compilation) !void { // Type of the export try writer.writeByte(0x00); // Exported function index - try leb.writeULEB128(writer, self.getFuncidx(exprt.exported_decl).?); + try leb.writeULEB128(writer, self.getFuncidx(exprt.exported_decl).? + 1); }, else => return error.TODOImplementNonFnDeclsForWasm, } @@ -235,7 +279,13 @@ pub fn flushModule(self: *Wasm, comp: *Compilation) !void { { const header_offset = try reserveVecSectionHeader(file); const writer = file.writer(); + var count: u32 = 0; for (self.funcs.items) |decl| { + // Do not emit any code for extern functions + if (decl.typed_value.most_recent.typed_value.val.tag() != .function) { + std.debug.print("Skipping decl: {s}\n", .{decl.name}); + continue; + } const fn_data = &decl.fn_link.wasm.?; // Write the already generated code to the file, inserting @@ -247,18 +297,20 @@ pub fn flushModule(self: *Wasm, comp: *Compilation) !void { // Use a fixed width here to make calculating the code size // in codegen.wasm.gen() simpler. var buf: [5]u8 = undefined; - leb.writeUnsignedFixed(5, &buf, self.getFuncidx(idx_ref.decl).?); + std.debug.print("idx_ref: {s} - {d}\n", .{ idx_ref.decl.name, self.getFuncidx(idx_ref.decl).? }); + leb.writeUnsignedFixed(5, &buf, self.getFuncidx(idx_ref.decl).? - 1); try writer.writeAll(&buf); } try writer.writeAll(fn_data.code.items[current..]); + count += 1; } try writeVecSectionHeader( file, header_offset, .code, @intCast(u32, (try file.getPos()) - header_offset - header_size), - @intCast(u32, self.funcs.items.len), + count, ); } } |