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translate_c.zig
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translate_c.zig
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//! This is the userland implementation of translate-c which is used by both stage1
//! and stage2.
const std = @import("std");
const testing = std.testing;
const assert = std.debug.assert;
const clang = @import("clang.zig");
const ctok = std.c.tokenizer;
const CToken = std.c.Token;
const mem = std.mem;
const math = std.math;
const meta = std.meta;
const ast = @import("translate_c/ast.zig");
const Node = ast.Node;
const Tag = Node.Tag;
const CallingConvention = std.builtin.CallingConvention;
pub const ClangErrMsg = clang.Stage2ErrorMsg;
pub const Error = std.mem.Allocator.Error;
const MacroProcessingError = Error || error{UnexpectedMacroToken};
const TypeError = Error || error{UnsupportedType};
const TransError = TypeError || error{UnsupportedTranslation};
const SymbolTable = std.StringArrayHashMap(Node);
const AliasList = std.ArrayList(struct {
alias: []const u8,
name: []const u8,
});
// Maps macro parameter names to token position, for determining if different
// identifiers refer to the same positional argument in different macros.
const ArgsPositionMap = std.StringArrayHashMapUnmanaged(usize);
const Scope = struct {
id: Id,
parent: ?*Scope,
const Id = enum {
block,
root,
condition,
loop,
do_loop,
};
/// Used for the scope of condition expressions, for example `if (cond)`.
/// The block is lazily initialised because it is only needed for rare
/// cases of comma operators being used.
const Condition = struct {
base: Scope,
block: ?Block = null,
fn getBlockScope(self: *Condition, c: *Context) !*Block {
if (self.block) |*b| return b;
self.block = try Block.init(c, &self.base, true);
return &self.block.?;
}
fn deinit(self: *Condition) void {
if (self.block) |*b| b.deinit();
}
};
/// Represents an in-progress Node.Block. This struct is stack-allocated.
/// When it is deinitialized, it produces an Node.Block which is allocated
/// into the main arena.
const Block = struct {
base: Scope,
statements: std.ArrayList(Node),
variables: AliasList,
mangle_count: u32 = 0,
label: ?[]const u8 = null,
/// By default all variables are discarded, since we do not know in advance if they
/// will be used. This maps the variable's name to the Discard payload, so that if
/// the variable is subsequently referenced we can indicate that the discard should
/// be skipped during the intermediate AST -> Zig AST render step.
variable_discards: std.StringArrayHashMap(*ast.Payload.Discard),
/// When the block corresponds to a function, keep track of the return type
/// so that the return expression can be cast, if necessary
return_type: ?clang.QualType = null,
/// C static local variables are wrapped in a block-local struct. The struct
/// is named after the (mangled) variable name, the Zig variable within the
/// struct itself is given this name.
const StaticInnerName = "static";
fn init(c: *Context, parent: *Scope, labeled: bool) !Block {
var blk = Block{
.base = .{
.id = .block,
.parent = parent,
},
.statements = std.ArrayList(Node).init(c.gpa),
.variables = AliasList.init(c.gpa),
.variable_discards = std.StringArrayHashMap(*ast.Payload.Discard).init(c.gpa),
};
if (labeled) {
blk.label = try blk.makeMangledName(c, "blk");
}
return blk;
}
fn deinit(self: *Block) void {
self.statements.deinit();
self.variables.deinit();
self.variable_discards.deinit();
self.* = undefined;
}
fn complete(self: *Block, c: *Context) !Node {
if (self.base.parent.?.id == .do_loop) {
// We reserve 1 extra statement if the parent is a do_loop. This is in case of
// do while, we want to put `if (cond) break;` at the end.
const alloc_len = self.statements.items.len + @boolToInt(self.base.parent.?.id == .do_loop);
var stmts = try c.arena.alloc(Node, alloc_len);
stmts.len = self.statements.items.len;
mem.copy(Node, stmts, self.statements.items);
return Tag.block.create(c.arena, .{
.label = self.label,
.stmts = stmts,
});
}
if (self.statements.items.len == 0) return Tag.empty_block.init();
return Tag.block.create(c.arena, .{
.label = self.label,
.stmts = try c.arena.dupe(Node, self.statements.items),
});
}
/// Given the desired name, return a name that does not shadow anything from outer scopes.
/// Inserts the returned name into the scope.
fn makeMangledName(scope: *Block, c: *Context, name: []const u8) ![]const u8 {
const name_copy = try c.arena.dupe(u8, name);
var proposed_name = name_copy;
while (scope.contains(proposed_name)) {
scope.mangle_count += 1;
proposed_name = try std.fmt.allocPrint(c.arena, "{s}_{d}", .{ name, scope.mangle_count });
}
try scope.variables.append(.{ .name = name_copy, .alias = proposed_name });
return proposed_name;
}
fn getAlias(scope: *Block, name: []const u8) []const u8 {
for (scope.variables.items) |p| {
if (mem.eql(u8, p.name, name))
return p.alias;
}
return scope.base.parent.?.getAlias(name);
}
fn localContains(scope: *Block, name: []const u8) bool {
for (scope.variables.items) |p| {
if (mem.eql(u8, p.alias, name))
return true;
}
return false;
}
fn contains(scope: *Block, name: []const u8) bool {
if (scope.localContains(name))
return true;
return scope.base.parent.?.contains(name);
}
fn discardVariable(scope: *Block, c: *Context, name: []const u8) Error!void {
const name_node = try Tag.identifier.create(c.arena, name);
const discard = try Tag.discard.create(c.arena, .{ .should_skip = false, .value = name_node });
try scope.statements.append(discard);
try scope.variable_discards.putNoClobber(name, discard.castTag(.discard).?);
}
};
const Root = struct {
base: Scope,
sym_table: SymbolTable,
macro_table: SymbolTable,
context: *Context,
nodes: std.ArrayList(Node),
fn init(c: *Context) Root {
return .{
.base = .{
.id = .root,
.parent = null,
},
.sym_table = SymbolTable.init(c.gpa),
.macro_table = SymbolTable.init(c.gpa),
.context = c,
.nodes = std.ArrayList(Node).init(c.gpa),
};
}
fn deinit(scope: *Root) void {
scope.sym_table.deinit();
scope.macro_table.deinit();
scope.nodes.deinit();
}
/// Check if the global scope contains this name, without looking into the "future", e.g.
/// ignore the preprocessed decl and macro names.
fn containsNow(scope: *Root, name: []const u8) bool {
return scope.sym_table.contains(name) or scope.macro_table.contains(name);
}
/// Check if the global scope contains the name, includes all decls that haven't been translated yet.
fn contains(scope: *Root, name: []const u8) bool {
return scope.containsNow(name) or scope.context.global_names.contains(name);
}
};
fn findBlockScope(inner: *Scope, c: *Context) !*Scope.Block {
var scope = inner;
while (true) {
switch (scope.id) {
.root => unreachable,
.block => return @fieldParentPtr(Block, "base", scope),
.condition => return @fieldParentPtr(Condition, "base", scope).getBlockScope(c),
else => scope = scope.parent.?,
}
}
}
fn findBlockReturnType(inner: *Scope, c: *Context) clang.QualType {
_ = c;
var scope = inner;
while (true) {
switch (scope.id) {
.root => unreachable,
.block => {
const block = @fieldParentPtr(Block, "base", scope);
if (block.return_type) |qt| return qt;
scope = scope.parent.?;
},
else => scope = scope.parent.?,
}
}
}
fn getAlias(scope: *Scope, name: []const u8) []const u8 {
return switch (scope.id) {
.root => return name,
.block => @fieldParentPtr(Block, "base", scope).getAlias(name),
.loop, .do_loop, .condition => scope.parent.?.getAlias(name),
};
}
fn contains(scope: *Scope, name: []const u8) bool {
return switch (scope.id) {
.root => @fieldParentPtr(Root, "base", scope).contains(name),
.block => @fieldParentPtr(Block, "base", scope).contains(name),
.loop, .do_loop, .condition => scope.parent.?.contains(name),
};
}
fn getBreakableScope(inner: *Scope) *Scope {
var scope = inner;
while (true) {
switch (scope.id) {
.root => unreachable,
.loop, .do_loop => return scope,
else => scope = scope.parent.?,
}
}
}
/// Appends a node to the first block scope if inside a function, or to the root tree if not.
fn appendNode(inner: *Scope, node: Node) !void {
var scope = inner;
while (true) {
switch (scope.id) {
.root => {
const root = @fieldParentPtr(Root, "base", scope);
return root.nodes.append(node);
},
.block => {
const block = @fieldParentPtr(Block, "base", scope);
return block.statements.append(node);
},
else => scope = scope.parent.?,
}
}
}
fn skipVariableDiscard(inner: *Scope, name: []const u8) void {
var scope = inner;
while (true) {
switch (scope.id) {
.root => return,
.block => {
const block = @fieldParentPtr(Block, "base", scope);
if (block.variable_discards.get(name)) |discard| {
discard.data.should_skip = true;
return;
}
},
else => {},
}
scope = scope.parent.?;
}
}
};
pub const Context = struct {
gpa: mem.Allocator,
arena: mem.Allocator,
source_manager: *clang.SourceManager,
decl_table: std.AutoArrayHashMapUnmanaged(usize, []const u8) = .{},
alias_list: AliasList,
global_scope: *Scope.Root,
clang_context: *clang.ASTContext,
mangle_count: u32 = 0,
/// Table of record decls that have been demoted to opaques.
opaque_demotes: std.AutoHashMapUnmanaged(usize, void) = .{},
/// Table of unnamed enums and records that are child types of typedefs.
unnamed_typedefs: std.AutoHashMapUnmanaged(usize, []const u8) = .{},
/// Needed to decide if we are parsing a typename
typedefs: std.StringArrayHashMapUnmanaged(void) = .{},
/// This one is different than the root scope's name table. This contains
/// a list of names that we found by visiting all the top level decls without
/// translating them. The other maps are updated as we translate; this one is updated
/// up front in a pre-processing step.
global_names: std.StringArrayHashMapUnmanaged(void) = .{},
pattern_list: PatternList,
/// This is used to emit different code depending on whether
/// the output zig source code is intended to be compiled with stage1 or stage2.
/// Ideally we will have stage1 and stage2 support the exact same Zig language,
/// but for now they diverge because I would rather focus on finishing and shipping
/// stage2 than implementing the features in stage1.
/// The list of differences are currently:
/// * function pointers in stage1 are e.g. `fn()void`
/// but in stage2 they are `*const fn()void`.
zig_is_stage1: bool,
fn getMangle(c: *Context) u32 {
c.mangle_count += 1;
return c.mangle_count;
}
/// Convert a null-terminated C string to a slice allocated in the arena
fn str(c: *Context, s: [*:0]const u8) ![]u8 {
return c.arena.dupe(u8, mem.sliceTo(s, 0));
}
/// Convert a clang source location to a file:line:column string
fn locStr(c: *Context, loc: clang.SourceLocation) ![]u8 {
const spelling_loc = c.source_manager.getSpellingLoc(loc);
const filename_c = c.source_manager.getFilename(spelling_loc);
const filename = if (filename_c) |s| try c.str(s) else @as([]const u8, "(no file)");
const line = c.source_manager.getSpellingLineNumber(spelling_loc);
const column = c.source_manager.getSpellingColumnNumber(spelling_loc);
return std.fmt.allocPrint(c.arena, "{s}:{d}:{d}", .{ filename, line, column });
}
};
pub fn translate(
gpa: mem.Allocator,
args_begin: [*]?[*]const u8,
args_end: [*]?[*]const u8,
errors: *[]ClangErrMsg,
resources_path: [*:0]const u8,
zig_is_stage1: bool,
) !std.zig.Ast {
// TODO stage2 bug
var tmp = errors;
const ast_unit = clang.LoadFromCommandLine(
args_begin,
args_end,
&tmp.ptr,
&tmp.len,
resources_path,
) orelse {
if (errors.len == 0) return error.ASTUnitFailure;
return error.SemanticAnalyzeFail;
};
defer ast_unit.delete();
// For memory that has the same lifetime as the Ast that we return
// from this function.
var arena_allocator = std.heap.ArenaAllocator.init(gpa);
errdefer arena_allocator.deinit();
const arena = arena_allocator.allocator();
var context = Context{
.gpa = gpa,
.arena = arena,
.source_manager = ast_unit.getSourceManager(),
.alias_list = AliasList.init(gpa),
.global_scope = try arena.create(Scope.Root),
.clang_context = ast_unit.getASTContext(),
.pattern_list = try PatternList.init(gpa),
.zig_is_stage1 = zig_is_stage1,
};
context.global_scope.* = Scope.Root.init(&context);
defer {
context.decl_table.deinit(gpa);
context.alias_list.deinit();
context.global_names.deinit(gpa);
context.opaque_demotes.deinit(gpa);
context.unnamed_typedefs.deinit(gpa);
context.typedefs.deinit(gpa);
context.global_scope.deinit();
context.pattern_list.deinit(gpa);
}
inline for (@typeInfo(std.zig.c_builtins).Struct.decls) |decl| {
if (decl.is_pub) {
const builtin = try Tag.pub_var_simple.create(arena, .{
.name = decl.name,
.init = try Tag.import_c_builtin.create(arena, decl.name),
});
try addTopLevelDecl(&context, decl.name, builtin);
}
}
try prepopulateGlobalNameTable(ast_unit, &context);
if (!ast_unit.visitLocalTopLevelDecls(&context, declVisitorC)) {
return error.OutOfMemory;
}
try transPreprocessorEntities(&context, ast_unit);
try addMacros(&context);
for (context.alias_list.items) |alias| {
if (!context.global_scope.sym_table.contains(alias.alias)) {
const node = try Tag.alias.create(arena, .{ .actual = alias.alias, .mangled = alias.name });
try addTopLevelDecl(&context, alias.alias, node);
}
}
return ast.render(gpa, context.global_scope.nodes.items);
}
fn prepopulateGlobalNameTable(ast_unit: *clang.ASTUnit, c: *Context) !void {
if (!ast_unit.visitLocalTopLevelDecls(c, declVisitorNamesOnlyC)) {
return error.OutOfMemory;
}
// TODO if we see #undef, delete it from the table
var it = ast_unit.getLocalPreprocessingEntities_begin();
const it_end = ast_unit.getLocalPreprocessingEntities_end();
while (it.I != it_end.I) : (it.I += 1) {
const entity = it.deref();
switch (entity.getKind()) {
.MacroDefinitionKind => {
const macro = @ptrCast(*clang.MacroDefinitionRecord, entity);
const raw_name = macro.getName_getNameStart();
const name = try c.str(raw_name);
try c.global_names.put(c.gpa, name, {});
},
else => {},
}
}
}
fn declVisitorNamesOnlyC(context: ?*anyopaque, decl: *const clang.Decl) callconv(.C) bool {
const c = @ptrCast(*Context, @alignCast(@alignOf(Context), context));
declVisitorNamesOnly(c, decl) catch return false;
return true;
}
fn declVisitorC(context: ?*anyopaque, decl: *const clang.Decl) callconv(.C) bool {
const c = @ptrCast(*Context, @alignCast(@alignOf(Context), context));
declVisitor(c, decl) catch return false;
return true;
}
fn declVisitorNamesOnly(c: *Context, decl: *const clang.Decl) Error!void {
if (decl.castToNamedDecl()) |named_decl| {
const decl_name = try c.str(named_decl.getName_bytes_begin());
try c.global_names.put(c.gpa, decl_name, {});
// Check for typedefs with unnamed enum/record child types.
if (decl.getKind() == .Typedef) {
const typedef_decl = @ptrCast(*const clang.TypedefNameDecl, decl);
var child_ty = typedef_decl.getUnderlyingType().getTypePtr();
const addr: usize = while (true) switch (child_ty.getTypeClass()) {
.Enum => {
const enum_ty = @ptrCast(*const clang.EnumType, child_ty);
const enum_decl = enum_ty.getDecl();
// check if this decl is unnamed
if (@ptrCast(*const clang.NamedDecl, enum_decl).getName_bytes_begin()[0] != 0) return;
break @ptrToInt(enum_decl.getCanonicalDecl());
},
.Record => {
const record_ty = @ptrCast(*const clang.RecordType, child_ty);
const record_decl = record_ty.getDecl();
// check if this decl is unnamed
if (@ptrCast(*const clang.NamedDecl, record_decl).getName_bytes_begin()[0] != 0) return;
break @ptrToInt(record_decl.getCanonicalDecl());
},
.Elaborated => {
const elaborated_ty = @ptrCast(*const clang.ElaboratedType, child_ty);
child_ty = elaborated_ty.getNamedType().getTypePtr();
},
.Decayed => {
const decayed_ty = @ptrCast(*const clang.DecayedType, child_ty);
child_ty = decayed_ty.getDecayedType().getTypePtr();
},
.Attributed => {
const attributed_ty = @ptrCast(*const clang.AttributedType, child_ty);
child_ty = attributed_ty.getEquivalentType().getTypePtr();
},
.MacroQualified => {
const macroqualified_ty = @ptrCast(*const clang.MacroQualifiedType, child_ty);
child_ty = macroqualified_ty.getModifiedType().getTypePtr();
},
else => return,
} else unreachable;
const result = try c.unnamed_typedefs.getOrPut(c.gpa, addr);
if (result.found_existing) {
// One typedef can declare multiple names.
// Don't put this one in `decl_table` so it's processed later.
return;
}
result.value_ptr.* = decl_name;
// Put this typedef in the decl_table to avoid redefinitions.
try c.decl_table.putNoClobber(c.gpa, @ptrToInt(typedef_decl.getCanonicalDecl()), decl_name);
try c.typedefs.put(c.gpa, decl_name, {});
}
}
}
fn declVisitor(c: *Context, decl: *const clang.Decl) Error!void {
switch (decl.getKind()) {
.Function => {
return visitFnDecl(c, @ptrCast(*const clang.FunctionDecl, decl));
},
.Typedef => {
try transTypeDef(c, &c.global_scope.base, @ptrCast(*const clang.TypedefNameDecl, decl));
},
.Enum => {
try transEnumDecl(c, &c.global_scope.base, @ptrCast(*const clang.EnumDecl, decl));
},
.Record => {
try transRecordDecl(c, &c.global_scope.base, @ptrCast(*const clang.RecordDecl, decl));
},
.Var => {
return visitVarDecl(c, @ptrCast(*const clang.VarDecl, decl), null);
},
.Empty => {
// Do nothing
},
.FileScopeAsm => {
try transFileScopeAsm(c, &c.global_scope.base, @ptrCast(*const clang.FileScopeAsmDecl, decl));
},
else => {
const decl_name = try c.str(decl.getDeclKindName());
try warn(c, &c.global_scope.base, decl.getLocation(), "ignoring {s} declaration", .{decl_name});
},
}
}
fn transFileScopeAsm(c: *Context, scope: *Scope, file_scope_asm: *const clang.FileScopeAsmDecl) Error!void {
const asm_string = file_scope_asm.getAsmString();
var len: usize = undefined;
const bytes_ptr = asm_string.getString_bytes_begin_size(&len);
const str = try std.fmt.allocPrint(c.arena, "\"{}\"", .{std.zig.fmtEscapes(bytes_ptr[0..len])});
const str_node = try Tag.string_literal.create(c.arena, str);
const asm_node = try Tag.asm_simple.create(c.arena, str_node);
const block = try Tag.block_single.create(c.arena, asm_node);
const comptime_node = try Tag.@"comptime".create(c.arena, block);
try scope.appendNode(comptime_node);
}
fn visitFnDecl(c: *Context, fn_decl: *const clang.FunctionDecl) Error!void {
const fn_name = try c.str(@ptrCast(*const clang.NamedDecl, fn_decl).getName_bytes_begin());
if (c.global_scope.sym_table.contains(fn_name))
return; // Avoid processing this decl twice
// Skip this declaration if a proper definition exists
if (!fn_decl.isThisDeclarationADefinition()) {
if (fn_decl.getDefinition()) |def|
return visitFnDecl(c, def);
}
const fn_decl_loc = fn_decl.getLocation();
const has_body = fn_decl.hasBody();
const storage_class = fn_decl.getStorageClass();
const is_always_inline = has_body and fn_decl.hasAlwaysInlineAttr();
var decl_ctx = FnDeclContext{
.fn_name = fn_name,
.has_body = has_body,
.storage_class = storage_class,
.is_always_inline = is_always_inline,
.is_export = switch (storage_class) {
.None => has_body and !is_always_inline and !fn_decl.isInlineSpecified(),
.Extern, .Static => false,
.PrivateExtern => return failDecl(c, fn_decl_loc, fn_name, "unsupported storage class: private extern", .{}),
.Auto => unreachable, // Not legal on functions
.Register => unreachable, // Not legal on functions
},
};
var fn_qt = fn_decl.getType();
const fn_type = while (true) {
const fn_type = fn_qt.getTypePtr();
switch (fn_type.getTypeClass()) {
.Attributed => {
const attr_type = @ptrCast(*const clang.AttributedType, fn_type);
fn_qt = attr_type.getEquivalentType();
},
.Paren => {
const paren_type = @ptrCast(*const clang.ParenType, fn_type);
fn_qt = paren_type.getInnerType();
},
else => break fn_type,
}
} else unreachable;
const fn_ty = @ptrCast(*const clang.FunctionType, fn_type);
const return_qt = fn_ty.getReturnType();
const proto_node = switch (fn_type.getTypeClass()) {
.FunctionProto => blk: {
const fn_proto_type = @ptrCast(*const clang.FunctionProtoType, fn_type);
if (has_body and fn_proto_type.isVariadic()) {
decl_ctx.has_body = false;
decl_ctx.storage_class = .Extern;
decl_ctx.is_export = false;
decl_ctx.is_always_inline = false;
try warn(c, &c.global_scope.base, fn_decl_loc, "TODO unable to translate variadic function, demoted to extern", .{});
}
break :blk transFnProto(c, fn_decl, fn_proto_type, fn_decl_loc, decl_ctx, true) catch |err| switch (err) {
error.UnsupportedType => {
return failDecl(c, fn_decl_loc, fn_name, "unable to resolve prototype of function", .{});
},
error.OutOfMemory => |e| return e,
};
},
.FunctionNoProto => blk: {
const fn_no_proto_type = @ptrCast(*const clang.FunctionType, fn_type);
break :blk transFnNoProto(c, fn_no_proto_type, fn_decl_loc, decl_ctx, true) catch |err| switch (err) {
error.UnsupportedType => {
return failDecl(c, fn_decl_loc, fn_name, "unable to resolve prototype of function", .{});
},
error.OutOfMemory => |e| return e,
};
},
else => return failDecl(c, fn_decl_loc, fn_name, "unable to resolve function type {}", .{fn_type.getTypeClass()}),
};
if (!decl_ctx.has_body) {
return addTopLevelDecl(c, fn_name, Node.initPayload(&proto_node.base));
}
// actual function definition with body
const body_stmt = fn_decl.getBody();
var block_scope = try Scope.Block.init(c, &c.global_scope.base, false);
block_scope.return_type = return_qt;
defer block_scope.deinit();
var scope = &block_scope.base;
var param_id: c_uint = 0;
for (proto_node.data.params) |*param| {
const param_name = param.name orelse {
proto_node.data.is_extern = true;
proto_node.data.is_export = false;
proto_node.data.is_inline = false;
try warn(c, &c.global_scope.base, fn_decl_loc, "function {s} parameter has no name, demoted to extern", .{fn_name});
return addTopLevelDecl(c, fn_name, Node.initPayload(&proto_node.base));
};
const c_param = fn_decl.getParamDecl(param_id);
const qual_type = c_param.getOriginalType();
const is_const = qual_type.isConstQualified();
const mangled_param_name = try block_scope.makeMangledName(c, param_name);
param.name = mangled_param_name;
if (!is_const) {
const bare_arg_name = try std.fmt.allocPrint(c.arena, "arg_{s}", .{mangled_param_name});
const arg_name = try block_scope.makeMangledName(c, bare_arg_name);
param.name = arg_name;
const redecl_node = try Tag.arg_redecl.create(c.arena, .{ .actual = mangled_param_name, .mangled = arg_name });
try block_scope.statements.append(redecl_node);
}
try block_scope.discardVariable(c, mangled_param_name);
param_id += 1;
}
const casted_body = @ptrCast(*const clang.CompoundStmt, body_stmt);
transCompoundStmtInline(c, casted_body, &block_scope) catch |err| switch (err) {
error.OutOfMemory => |e| return e,
error.UnsupportedTranslation,
error.UnsupportedType,
=> {
proto_node.data.is_extern = true;
proto_node.data.is_export = false;
proto_node.data.is_inline = false;
try warn(c, &c.global_scope.base, fn_decl_loc, "unable to translate function, demoted to extern", .{});
return addTopLevelDecl(c, fn_name, Node.initPayload(&proto_node.base));
},
};
// add return statement if the function didn't have one
blk: {
const maybe_body = try block_scope.complete(c);
if (fn_ty.getNoReturnAttr() or isAnyopaque(return_qt) or maybe_body.isNoreturn(false)) {
proto_node.data.body = maybe_body;
break :blk;
}
const rhs = transZeroInitExpr(c, scope, fn_decl_loc, return_qt.getTypePtr()) catch |err| switch (err) {
error.OutOfMemory => |e| return e,
error.UnsupportedTranslation,
error.UnsupportedType,
=> {
proto_node.data.is_extern = true;
proto_node.data.is_export = false;
proto_node.data.is_inline = false;
try warn(c, &c.global_scope.base, fn_decl_loc, "unable to create a return value for function, demoted to extern", .{});
return addTopLevelDecl(c, fn_name, Node.initPayload(&proto_node.base));
},
};
const ret = try Tag.@"return".create(c.arena, rhs);
try block_scope.statements.append(ret);
proto_node.data.body = try block_scope.complete(c);
}
return addTopLevelDecl(c, fn_name, Node.initPayload(&proto_node.base));
}
fn transQualTypeMaybeInitialized(c: *Context, scope: *Scope, qt: clang.QualType, decl_init: ?*const clang.Expr, loc: clang.SourceLocation) TransError!Node {
return if (decl_init) |init_expr|
transQualTypeInitialized(c, scope, qt, init_expr, loc)
else
transQualType(c, scope, qt, loc);
}
/// This is used in global scope to convert a string literal `S` to [*c]u8:
/// &(struct {
/// var static = S.*;
/// }).static;
fn stringLiteralToCharStar(c: *Context, str: Node) Error!Node {
const var_name = Scope.Block.StaticInnerName;
const variables = try c.arena.alloc(Node, 1);
variables[0] = try Tag.mut_str.create(c.arena, .{ .name = var_name, .init = str });
const anon_struct = try Tag.@"struct".create(c.arena, .{
.layout = .none,
.fields = &.{},
.functions = &.{},
.variables = variables,
});
const member_access = try Tag.field_access.create(c.arena, .{
.lhs = anon_struct,
.field_name = var_name,
});
return Tag.address_of.create(c.arena, member_access);
}
/// if mangled_name is not null, this var decl was declared in a block scope.
fn visitVarDecl(c: *Context, var_decl: *const clang.VarDecl, mangled_name: ?[]const u8) Error!void {
const var_name = mangled_name orelse try c.str(@ptrCast(*const clang.NamedDecl, var_decl).getName_bytes_begin());
if (c.global_scope.sym_table.contains(var_name))
return; // Avoid processing this decl twice
const is_pub = mangled_name == null;
const is_threadlocal = var_decl.getTLSKind() != .None;
const scope = &c.global_scope.base;
const var_decl_loc = var_decl.getLocation();
const qual_type = var_decl.getTypeSourceInfo_getType();
const storage_class = var_decl.getStorageClass();
const is_const = qual_type.isConstQualified();
const has_init = var_decl.hasInit();
const decl_init = var_decl.getInit();
// In C extern variables with initializers behave like Zig exports.
// extern int foo = 2;
// does the same as:
// extern int foo;
// int foo = 2;
var is_extern = storage_class == .Extern and !has_init;
var is_export = !is_extern and storage_class != .Static;
if (!is_extern and qualTypeWasDemotedToOpaque(c, qual_type)) {
return failDecl(c, var_decl_loc, var_name, "non-extern variable has opaque type", .{});
}
const type_node = transQualTypeMaybeInitialized(c, scope, qual_type, decl_init, var_decl_loc) catch |err| switch (err) {
error.UnsupportedTranslation, error.UnsupportedType => {
return failDecl(c, var_decl_loc, var_name, "unable to resolve variable type", .{});
},
error.OutOfMemory => |e| return e,
};
var init_node: ?Node = null;
// If the initialization expression is not present, initialize with undefined.
// If it is an integer literal, we can skip the @as since it will be redundant
// with the variable type.
if (has_init) trans_init: {
if (decl_init) |expr| {
const node_or_error = if (expr.getStmtClass() == .StringLiteralClass)
transStringLiteralInitializer(c, scope, @ptrCast(*const clang.StringLiteral, expr), type_node)
else
transExprCoercing(c, scope, expr, .used);
init_node = node_or_error catch |err| switch (err) {
error.UnsupportedTranslation,
error.UnsupportedType,
=> {
is_extern = true;
is_export = false;
try warn(c, scope, var_decl_loc, "unable to translate variable initializer, demoted to extern", .{});
break :trans_init;
},
error.OutOfMemory => |e| return e,
};
if (!qualTypeIsBoolean(qual_type) and isBoolRes(init_node.?)) {
init_node = try Tag.bool_to_int.create(c.arena, init_node.?);
} else if (init_node.?.tag() == .string_literal and qualTypeIsCharStar(qual_type)) {
init_node = try stringLiteralToCharStar(c, init_node.?);
}
} else {
init_node = Tag.undefined_literal.init();
}
} else if (storage_class != .Extern) {
// The C language specification states that variables with static or threadlocal
// storage without an initializer are initialized to a zero value.
// std.mem.zeroes(T)
init_node = try Tag.std_mem_zeroes.create(c.arena, type_node);
}
const linksection_string = blk: {
var str_len: usize = undefined;
if (var_decl.getSectionAttribute(&str_len)) |str_ptr| {
break :blk str_ptr[0..str_len];
}
break :blk null;
};
const node = try Tag.var_decl.create(c.arena, .{
.is_pub = is_pub,
.is_const = is_const,
.is_extern = is_extern,
.is_export = is_export,
.is_threadlocal = is_threadlocal,
.linksection_string = linksection_string,
.alignment = zigAlignment(var_decl.getAlignedAttribute(c.clang_context)),
.name = var_name,
.type = type_node,
.init = init_node,
});
return addTopLevelDecl(c, var_name, node);
}
const builtin_typedef_map = std.ComptimeStringMap([]const u8, .{
.{ "uint8_t", "u8" },
.{ "int8_t", "i8" },
.{ "uint16_t", "u16" },
.{ "int16_t", "i16" },
.{ "uint32_t", "u32" },
.{ "int32_t", "i32" },
.{ "uint64_t", "u64" },
.{ "int64_t", "i64" },
.{ "intptr_t", "isize" },
.{ "uintptr_t", "usize" },
.{ "ssize_t", "isize" },
.{ "size_t", "usize" },
});
fn transTypeDef(c: *Context, scope: *Scope, typedef_decl: *const clang.TypedefNameDecl) Error!void {
if (c.decl_table.get(@ptrToInt(typedef_decl.getCanonicalDecl()))) |_|
return; // Avoid processing this decl twice
const toplevel = scope.id == .root;
const bs: *Scope.Block = if (!toplevel) try scope.findBlockScope(c) else undefined;
var name: []const u8 = try c.str(@ptrCast(*const clang.NamedDecl, typedef_decl).getName_bytes_begin());
try c.typedefs.put(c.gpa, name, {});
if (builtin_typedef_map.get(name)) |builtin| {
return c.decl_table.putNoClobber(c.gpa, @ptrToInt(typedef_decl.getCanonicalDecl()), builtin);
}
if (!toplevel) name = try bs.makeMangledName(c, name);
try c.decl_table.putNoClobber(c.gpa, @ptrToInt(typedef_decl.getCanonicalDecl()), name);
const child_qt = typedef_decl.getUnderlyingType();
const typedef_loc = typedef_decl.getLocation();
const init_node = transQualType(c, scope, child_qt, typedef_loc) catch |err| switch (err) {
error.UnsupportedType => {
return failDecl(c, typedef_loc, name, "unable to resolve typedef child type", .{});
},
error.OutOfMemory => |e| return e,
};
const payload = try c.arena.create(ast.Payload.SimpleVarDecl);
payload.* = .{
.base = .{ .tag = ([2]Tag{ .var_simple, .pub_var_simple })[@boolToInt(toplevel)] },
.data = .{
.name = name,
.init = init_node,
},
};
const node = Node.initPayload(&payload.base);
if (toplevel) {
try addTopLevelDecl(c, name, node);
} else {
try scope.appendNode(node);
if (node.tag() != .pub_var_simple) {
try bs.discardVariable(c, name);
}
}
}
/// Build a getter function for a flexible array member at the end of a C struct
/// e.g. `T items[]` or `T items[0]`. The generated function returns a [*c] pointer
/// to the flexible array with the correct const and volatile qualifiers
fn buildFlexibleArrayFn(
c: *Context,
scope: *Scope,
layout: *const clang.ASTRecordLayout,
field_name: []const u8,
field_decl: *const clang.FieldDecl,
) TypeError!Node {
const field_qt = field_decl.getType();
const u8_type = try Tag.type.create(c.arena, "u8");
const self_param_name = "self";
const self_param = try Tag.identifier.create(c.arena, self_param_name);
const self_type = try Tag.typeof.create(c.arena, self_param);
const fn_params = try c.arena.alloc(ast.Payload.Param, 1);
fn_params[0] = .{
.name = self_param_name,
.type = Tag.@"anytype".init(),
.is_noalias = false,
};
const array_type = @ptrCast(*const clang.ArrayType, field_qt.getTypePtr());
const element_qt = array_type.getElementType();
const element_type = try transQualType(c, scope, element_qt, field_decl.getLocation());
var block_scope = try Scope.Block.init(c, scope, false);
defer block_scope.deinit();
const intermediate_type_name = try block_scope.makeMangledName(c, "Intermediate");
const intermediate_type = try Tag.helpers_flexible_array_type.create(c.arena, .{ .lhs = self_type, .rhs = u8_type });
const intermediate_type_decl = try Tag.var_simple.create(c.arena, .{
.name = intermediate_type_name,
.init = intermediate_type,
});
try block_scope.statements.append(intermediate_type_decl);
const intermediate_type_ident = try Tag.identifier.create(c.arena, intermediate_type_name);
const return_type_name = try block_scope.makeMangledName(c, "ReturnType");
const return_type = try Tag.helpers_flexible_array_type.create(c.arena, .{ .lhs = self_type, .rhs = element_type });
const return_type_decl = try Tag.var_simple.create(c.arena, .{
.name = return_type_name,
.init = return_type,
});
try block_scope.statements.append(return_type_decl);
const return_type_ident = try Tag.identifier.create(c.arena, return_type_name);
const field_index = field_decl.getFieldIndex();
const bit_offset = layout.getFieldOffset(field_index); // this is a target-specific constant based on the struct layout
const byte_offset = bit_offset / 8;
const casted_self = try Tag.ptr_cast.create(c.arena, .{
.lhs = intermediate_type_ident,
.rhs = self_param,
});
const field_offset = try transCreateNodeNumber(c, byte_offset, .int);
const field_ptr = try Tag.add.create(c.arena, .{ .lhs = casted_self, .rhs = field_offset });
const alignment = try Tag.alignof.create(c.arena, element_type);
const ptr_val = try Tag.align_cast.create(c.arena, .{ .lhs = alignment, .rhs = field_ptr });
const ptr_cast = try Tag.ptr_cast.create(c.arena, .{ .lhs = return_type_ident, .rhs = ptr_val });
const return_stmt = try Tag.@"return".create(c.arena, ptr_cast);
try block_scope.statements.append(return_stmt);
const payload = try c.arena.create(ast.Payload.Func);
payload.* = .{
.base = .{ .tag = .func },
.data = .{
.is_pub = true,
.is_extern = false,