Commit a6f7a9ce2b

Andrew Kelley <andrew@ziglang.org>
2019-05-10 22:03:54
translate-c: we have our first test of self-hosted
See #1964
1 parent d065f29
src/translate_c.cpp
@@ -4038,15 +4038,15 @@ static void visit_fn_decl(Context *c, const ZigClangFunctionDecl *fn_decl) {
     }
 
     proto_node->data.fn_proto.name = fn_name;
-    proto_node->data.fn_proto.is_extern = !((const clang::FunctionDecl*)fn_decl)->hasBody();
+    proto_node->data.fn_proto.is_extern = !ZigClangFunctionDecl_hasBody(fn_decl);
 
-    clang::StorageClass sc = ((const clang::FunctionDecl*)fn_decl)->getStorageClass();
-    if (sc == clang::SC_None) {
+    ZigClangStorageClass sc = ZigClangFunctionDecl_getStorageClass(fn_decl);
+    if (sc == ZigClangStorageClass_None) {
         proto_node->data.fn_proto.visib_mod = c->visib_mod;
-        proto_node->data.fn_proto.is_export = ((const clang::FunctionDecl*)fn_decl)->hasBody() ? c->want_export : false;
-    } else if (sc == clang::SC_Extern || sc == clang::SC_Static) {
+        proto_node->data.fn_proto.is_export = ZigClangFunctionDecl_hasBody(fn_decl) ? c->want_export : false;
+    } else if (sc == ZigClangStorageClass_Extern || sc == ZigClangStorageClass_Static) {
         proto_node->data.fn_proto.visib_mod = c->visib_mod;
-    } else if (sc == clang::SC_PrivateExtern) {
+    } else if (sc == ZigClangStorageClass_PrivateExtern) {
         emit_warning(c, ZigClangFunctionDecl_getLocation(fn_decl), "unsupported storage class: private extern");
         return;
     } else {
@@ -4058,7 +4058,7 @@ static void visit_fn_decl(Context *c, const ZigClangFunctionDecl *fn_decl) {
 
     for (size_t i = 0; i < proto_node->data.fn_proto.params.length; i += 1) {
         AstNode *param_node = proto_node->data.fn_proto.params.at(i);
-        const clang::ParmVarDecl *param = ((const clang::FunctionDecl*)fn_decl)->getParamDecl(i);
+        const ZigClangParmVarDecl *param = ZigClangFunctionDecl_getParamDecl(fn_decl, i);
         const char *name = ZigClangDecl_getName_bytes_begin((const ZigClangDecl *)param);
 
         Buf *proto_param_name;
@@ -4077,7 +4077,7 @@ static void visit_fn_decl(Context *c, const ZigClangFunctionDecl *fn_decl) {
         param_node->data.param_decl.name = scope_var->zig_name;
     }
 
-    if (!((const clang::FunctionDecl*)fn_decl)->hasBody()) {
+    if (!ZigClangFunctionDecl_hasBody(fn_decl)) {
         // just a prototype
         add_top_level_decl(c, proto_node->data.fn_proto.name, proto_node);
         return;
@@ -4085,7 +4085,7 @@ static void visit_fn_decl(Context *c, const ZigClangFunctionDecl *fn_decl) {
 
     // actual function definition with body
     c->ptr_params.clear();
-    const ZigClangStmt *body = bitcast(((const clang::FunctionDecl*)fn_decl)->getBody());
+    const ZigClangStmt *body = ZigClangFunctionDecl_getBody(fn_decl);
     AstNode *actual_body_node;
     TransScope *result_scope = trans_stmt(c, scope, body, &actual_body_node);
     if (result_scope == nullptr) {
src/zig_clang.cpp
@@ -1236,6 +1236,25 @@ static_assert((clang::CallingConv)ZigClangCallingConv_PreserveMost == clang::CC_
 static_assert((clang::CallingConv)ZigClangCallingConv_PreserveAll == clang::CC_PreserveAll, "");
 static_assert((clang::CallingConv)ZigClangCallingConv_AArch64VectorCall == clang::CC_AArch64VectorCall, "");
 
+void ZigClang_detect_enum_StorageClass(clang::StorageClass x) {
+    switch (x) {
+        case clang::SC_None:
+        case clang::SC_Extern:
+        case clang::SC_Static:
+        case clang::SC_PrivateExtern:
+        case clang::SC_Auto:
+        case clang::SC_Register:
+            break;
+    }
+}
+
+static_assert((clang::StorageClass)ZigClangStorageClass_None == clang::SC_None, "");
+static_assert((clang::StorageClass)ZigClangStorageClass_Extern == clang::SC_Extern, "");
+static_assert((clang::StorageClass)ZigClangStorageClass_Static == clang::SC_Static, "");
+static_assert((clang::StorageClass)ZigClangStorageClass_PrivateExtern == clang::SC_PrivateExtern, "");
+static_assert((clang::StorageClass)ZigClangStorageClass_Auto == clang::SC_Auto, "");
+static_assert((clang::StorageClass)ZigClangStorageClass_Register == clang::SC_Register, "");
+
 
 static_assert(sizeof(ZigClangSourceLocation) == sizeof(clang::SourceLocation), "");
 static ZigClangSourceLocation bitcast(clang::SourceLocation src) {
@@ -1434,6 +1453,30 @@ struct ZigClangSourceLocation ZigClangFunctionDecl_getLocation(const struct ZigC
     return bitcast(casted->getLocation());
 }
 
+bool ZigClangFunctionDecl_hasBody(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    return casted->hasBody();
+}
+
+enum ZigClangStorageClass ZigClangFunctionDecl_getStorageClass(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    return (ZigClangStorageClass)casted->getStorageClass();
+}
+
+const struct ZigClangParmVarDecl *ZigClangFunctionDecl_getParamDecl(const struct ZigClangFunctionDecl *self,
+        unsigned i)
+{
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    const clang::ParmVarDecl *parm_var_decl = casted->getParamDecl(i);
+    return reinterpret_cast<const ZigClangParmVarDecl *>(parm_var_decl);
+}
+
+const struct ZigClangStmt *ZigClangFunctionDecl_getBody(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    const clang::Stmt *stmt = casted->getBody();
+    return reinterpret_cast<const ZigClangStmt *>(stmt);
+}
+
 const ZigClangTypedefNameDecl *ZigClangTypedefType_getDecl(const ZigClangTypedefType *self) {
     auto casted = reinterpret_cast<const clang::TypedefType *>(self);
     const clang::TypedefNameDecl *name_decl = casted->getDecl();
src/zig_clang.h
@@ -88,7 +88,6 @@ struct ZigClangSkipFunctionBodiesScope;
 struct ZigClangSourceManager;
 struct ZigClangSourceRange;
 struct ZigClangStmt;
-struct ZigClangStorageClass;
 struct ZigClangStringLiteral;
 struct ZigClangStringRef;
 struct ZigClangSwitchStmt;
@@ -700,6 +699,18 @@ enum ZigClangCallingConv {
     ZigClangCallingConv_AArch64VectorCall, // __attribute__((aarch64_vector_pcs))
 };
 
+enum ZigClangStorageClass {
+    // These are legal on both functions and variables.
+    ZigClangStorageClass_None,
+    ZigClangStorageClass_Extern,
+    ZigClangStorageClass_Static,
+    ZigClangStorageClass_PrivateExtern,
+
+    // These are only legal on variables.
+    ZigClangStorageClass_Auto,
+    ZigClangStorageClass_Register,
+};
+
 ZIG_EXTERN_C struct ZigClangSourceLocation ZigClangSourceManager_getSpellingLoc(const struct ZigClangSourceManager *,
         struct ZigClangSourceLocation Loc);
 ZIG_EXTERN_C const char *ZigClangSourceManager_getFilename(const struct ZigClangSourceManager *,
@@ -742,6 +753,10 @@ ZIG_EXTERN_C struct ZigClangSourceLocation ZigClangDecl_getLocation(const struct
 
 ZIG_EXTERN_C struct ZigClangQualType ZigClangFunctionDecl_getType(const struct ZigClangFunctionDecl *);
 ZIG_EXTERN_C struct ZigClangSourceLocation ZigClangFunctionDecl_getLocation(const struct ZigClangFunctionDecl *);
+ZIG_EXTERN_C bool ZigClangFunctionDecl_hasBody(const struct ZigClangFunctionDecl *);
+ZIG_EXTERN_C enum ZigClangStorageClass ZigClangFunctionDecl_getStorageClass(const struct ZigClangFunctionDecl *);
+ZIG_EXTERN_C const struct ZigClangParmVarDecl *ZigClangFunctionDecl_getParamDecl(const struct ZigClangFunctionDecl *, unsigned i);
+ZIG_EXTERN_C const struct ZigClangStmt *ZigClangFunctionDecl_getBody(const struct ZigClangFunctionDecl *);
 
 ZIG_EXTERN_C bool ZigClangRecordDecl_isUnion(const struct ZigClangRecordDecl *record_decl);
 ZIG_EXTERN_C bool ZigClangRecordDecl_isStruct(const struct ZigClangRecordDecl *record_decl);
src-self-hosted/clang.zig
@@ -56,7 +56,6 @@ pub const struct_ZigClangSkipFunctionBodiesScope = @OpaqueType();
 pub const struct_ZigClangSourceManager = @OpaqueType();
 pub const struct_ZigClangSourceRange = @OpaqueType();
 pub const struct_ZigClangStmt = @OpaqueType();
-pub const struct_ZigClangStorageClass = @OpaqueType();
 pub const struct_ZigClangStringLiteral = @OpaqueType();
 pub const struct_ZigClangStringRef = @OpaqueType();
 pub const struct_ZigClangSwitchStmt = @OpaqueType();
@@ -513,6 +512,10 @@ pub extern fn ZigClangASTUnit_delete(arg0: ?*struct_ZigClangASTUnit) void;
 
 pub extern fn ZigClangFunctionDecl_getType(self: *const struct_ZigClangFunctionDecl) struct_ZigClangQualType;
 pub extern fn ZigClangFunctionDecl_getLocation(self: *const struct_ZigClangFunctionDecl) struct_ZigClangSourceLocation;
+pub extern fn ZigClangFunctionDecl_hasBody(self: *const struct_ZigClangFunctionDecl) bool;
+pub extern fn ZigClangFunctionDecl_getStorageClass(self: *const struct_ZigClangFunctionDecl) ZigClangStorageClass;
+pub extern fn ZigClangFunctionDecl_getParamDecl(self: *const struct_ZigClangFunctionDecl, i: c_uint) *const struct_ZigClangParmVarDecl;
+
 pub extern fn ZigClangBuiltinType_getKind(self: *const struct_ZigClangBuiltinType) ZigClangBuiltinTypeKind;
 
 pub extern fn ZigClangFunctionType_getNoReturnAttr(self: *const ZigClangFunctionType) bool;
@@ -584,7 +587,6 @@ pub const ZigClangSkipFunctionBodiesScope = struct_ZigClangSkipFunctionBodiesSco
 pub const ZigClangSourceManager = struct_ZigClangSourceManager;
 pub const ZigClangSourceRange = struct_ZigClangSourceRange;
 pub const ZigClangStmt = struct_ZigClangStmt;
-pub const ZigClangStorageClass = struct_ZigClangStorageClass;
 pub const ZigClangStringLiteral = struct_ZigClangStringLiteral;
 pub const ZigClangStringRef = struct_ZigClangStringRef;
 pub const ZigClangSwitchStmt = struct_ZigClangSwitchStmt;
@@ -849,3 +851,12 @@ pub const ZigClangCallingConv = extern enum {
     PreserveAll,
     AArch64VectorCall,
 };
+
+pub const ZigClangStorageClass = extern enum {
+    None,
+    Extern,
+    Static,
+    PrivateExtern,
+    Auto,
+    Register,
+};
src-self-hosted/translate_c.zig
@@ -2,6 +2,7 @@
 // and stage2. Currently the only way it is used is with `zig translate-c-2`.
 
 const std = @import("std");
+const builtin = @import("builtin");
 const ast = std.zig.ast;
 const Token = std.zig.Token;
 use @import("clang.zig");
@@ -12,13 +13,7 @@ pub const Mode = enum {
 };
 
 // TODO merge with Type.Fn.CallingConvention
-pub const CallingConvention = enum {
-    auto,
-    c,
-    cold,
-    naked,
-    stdcall,
-};
+const CallingConvention = builtin.TypeInfo.CallingConvention;
 
 pub const ClangErrMsg = Stage2ErrorMsg;
 
@@ -27,11 +22,64 @@ pub const Error = error{
     UnsupportedType,
 };
 
+const DeclTable = std.HashMap(usize, void, addrHash, addrEql);
+
+fn addrHash(x: usize) u32 {
+    switch (@typeInfo(usize).Int.bits) {
+        32 => return x,
+        // pointers are usually aligned so we ignore the bits that are probably all 0 anyway
+        // usually the larger bits of addr space are unused so we just chop em off
+        64 => return @truncate(u32, x >> 4),
+        else => @compileError("unreachable"),
+    }
+}
+
+fn addrEql(a: usize, b: usize) bool {
+    return a == b;
+}
+
+const Scope = struct {
+    id: Id,
+    parent: ?*Scope,
+
+    const Id = enum {
+        Switch,
+        Var,
+        Block,
+        Root,
+        While,
+    };
+    const Switch = struct {
+        base: Scope,
+    };
+
+    const Var = struct {
+        base: Scope,
+        c_name: []const u8,
+        zig_name: []const u8,
+    };
+
+    const Block = struct {
+        base: Scope,
+    };
+
+    const Root = struct {
+        base: Scope,
+    };
+
+    const While = struct {
+        base: Scope,
+    };
+};
+
 const Context = struct {
     tree: *ast.Tree,
     source_buffer: *std.Buffer,
     err: Error,
     source_manager: *ZigClangSourceManager,
+    decl_table: DeclTable,
+    global_scope: *Scope.Root,
+    mode: Mode,
 
     fn a(c: *Context) *std.mem.Allocator {
         return &c.tree.arena_allocator.allocator;
@@ -76,7 +124,7 @@ pub fn translate(
 
     var tree_arena = std.heap.ArenaAllocator.init(backing_allocator);
     errdefer tree_arena.deinit();
-    const arena = &tree_arena.allocator;
+    var arena = &tree_arena.allocator;
 
     const root_node = try arena.create(ast.Node.Root);
     root_node.* = ast.Node.Root{
@@ -96,14 +144,24 @@ pub fn translate(
         .errors = ast.Tree.ErrorList.init(arena),
     };
     tree.arena_allocator = tree_arena;
+    arena = &tree.arena_allocator.allocator;
 
-    var source_buffer = try std.Buffer.initSize(&tree.arena_allocator.allocator, 0);
+    var source_buffer = try std.Buffer.initSize(arena, 0);
 
     var context = Context{
         .tree = tree,
         .source_buffer = &source_buffer,
         .source_manager = ZigClangASTUnit_getSourceManager(ast_unit),
         .err = undefined,
+        .decl_table = DeclTable.init(arena),
+        .global_scope = try arena.create(Scope.Root),
+        .mode = mode,
+    };
+    context.global_scope.* = Scope.Root{
+        .base = Scope{
+            .id = Scope.Id.Root,
+            .parent = null,
+        },
     };
 
     if (!ZigClangASTUnit_visitLocalTopLevelDecls(ast_unit, &context, declVisitorC)) {
@@ -149,27 +207,39 @@ fn declVisitor(c: *Context, decl: *const ZigClangDecl) Error!void {
 }
 
 fn visitFnDecl(c: *Context, fn_decl: *const ZigClangFunctionDecl) Error!void {
-    const fn_name = try c.str(ZigClangDecl_getName_bytes_begin(@ptrCast(*const ZigClangDecl, fn_decl)));
-
-    // TODO The C++ code has this:
-    //if (get_global(c, fn_name)) {
-    //    // we already saw this function
-    //    return;
-    //}
+    if (try c.decl_table.put(@ptrToInt(fn_decl), {})) |_| return; // Avoid processing this decl twice
 
+    const fn_name = try c.str(ZigClangDecl_getName_bytes_begin(@ptrCast(*const ZigClangDecl, fn_decl)));
     const fn_decl_loc = ZigClangFunctionDecl_getLocation(fn_decl);
-    const proto_node = transQualType(c, ZigClangFunctionDecl_getType(fn_decl), fn_decl_loc) catch |e| switch (e) {
-        error.UnsupportedType => {
-            try failDecl(c, fn_decl_loc, fn_name, "unable to resolve prototype of function");
-            return;
+    const fn_qt = ZigClangFunctionDecl_getType(fn_decl);
+    const fn_type = ZigClangQualType_getTypePtr(fn_qt);
+    const proto_node = switch (ZigClangType_getTypeClass(fn_type)) {
+        .FunctionProto => transFnProto(
+            c,
+            @ptrCast(*const ZigClangFunctionProtoType, fn_type),
+            fn_decl_loc,
+            fn_decl,
+            fn_name,
+        ) catch |err| switch (err) {
+            error.UnsupportedType => {
+                return failDecl(c, fn_decl_loc, fn_name, "unable to resolve prototype of function");
+            },
+            else => return err,
         },
-        else => return e,
+        .FunctionNoProto => return failDecl(c, fn_decl_loc, fn_name, "TODO support functions with no prototype"),
+        else => unreachable,
     };
-    const semi_tok = try appendToken(c, .Semicolon, ";");
 
-    try emitWarning(c, fn_decl_loc, "TODO implement more translate-c for function decls");
+    if (!ZigClangFunctionDecl_hasBody(fn_decl)) {
+        const semi_tok = try appendToken(c, .Semicolon, ";");
+        return addTopLevelDecl(c, fn_name, &proto_node.base);
+    }
+
+    try emitWarning(c, fn_decl_loc, "TODO implement function body translation");
+}
 
-    try c.tree.root_node.decls.push(proto_node);
+fn addTopLevelDecl(c: *Context, name: []const u8, decl_node: *ast.Node) !void {
+    try c.tree.root_node.decls.push(decl_node);
 }
 
 fn transQualType(c: *Context, qt: ZigClangQualType, source_loc: ZigClangSourceLocation) !*ast.Node {
@@ -205,91 +275,7 @@ fn transType(c: *Context, ty: *const ZigClangType, source_loc: ZigClangSourceLoc
                 else => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported builtin type"),
             }
         },
-        .FunctionProto => {
-            const fn_ty = @ptrCast(*const ZigClangFunctionType, ty);
-            const cc = switch (ZigClangFunctionType_getCallConv(fn_ty)) {
-                .C => CallingConvention.c,
-                .X86StdCall => CallingConvention.stdcall,
-                .X86FastCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 fastcall"),
-                .X86ThisCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 thiscall"),
-                .X86VectorCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 vectorcall"),
-                .X86Pascal => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 pascal"),
-                .Win64 => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: win64"),
-                .X86_64SysV => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 64sysv"),
-                .X86RegCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 reg"),
-                .AAPCS => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: aapcs"),
-                .AAPCS_VFP => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: aapcs-vfp"),
-                .IntelOclBicc => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: intel_ocl_bicc"),
-                .SpirFunction => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: SPIR function"),
-                .OpenCLKernel => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: OpenCLKernel"),
-                .Swift => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: Swift"),
-                .PreserveMost => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: PreserveMost"),
-                .PreserveAll => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: PreserveAll"),
-                .AArch64VectorCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: AArch64VectorCall"),
-            };
-
-            const fn_proto_ty = @ptrCast(*const ZigClangFunctionProtoType, ty);
-            const is_var_args = ZigClangFunctionProtoType_isVariadic(fn_proto_ty);
-            const param_count: usize = ZigClangFunctionProtoType_getNumParams(fn_proto_ty);
-            var i: usize = 0;
-            while (i < param_count) : (i += 1) {
-                return revertAndWarn(rp, error.UnsupportedType, source_loc, "TODO: implement parameters for FunctionProto in transType");
-            }
-            // TODO check for always_inline attribute
-            // TODO check for align attribute
-
-            // extern fn (...) T
-            const cc_tok = if (cc == .stdcall) try appendToken(c, .Keyword_stdcallcc, "stdcallcc") else null;
-            const extern_tok = if (cc == .c) try appendToken(c, .Keyword_extern, "extern") else null;
-            const fn_tok = try appendToken(c, .Keyword_fn, "fn");
-            const lparen_tok = try appendToken(c, .LParen, "(");
-            const var_args_tok = if (is_var_args) try appendToken(c, .Ellipsis3, "...") else null;
-            const rparen_tok = try appendToken(c, .RParen, ")");
-
-            const return_type_node = blk: {
-                if (ZigClangFunctionType_getNoReturnAttr(fn_ty)) {
-                    break :blk try appendIdentifier(c, "noreturn");
-                } else {
-                    return revertAndWarn(rp, error.UnsupportedType, source_loc, "TODO: non-noreturn FunctionProto return type");
-                    //proto_node->data.fn_proto.return_type = trans_qual_type(c,
-                    //        ZigClangFunctionType_getReturnType(fn_ty), source_loc);
-                    //if (proto_node->data.fn_proto.return_type == nullptr) {
-                    //    emit_warning(c, source_loc, "unsupported function proto return type");
-                    //    return nullptr;
-                    //}
-                    //// convert c_void to actual void (only for return type)
-                    //// we do want to look at the AstNode instead of ZigClangQualType, because
-                    //// if they do something like:
-                    ////     typedef Foo void;
-                    ////     void foo(void) -> Foo;
-                    //// we want to keep the return type AST node.
-                    //if (is_c_void_type(proto_node->data.fn_proto.return_type)) {
-                    //    proto_node->data.fn_proto.return_type = trans_create_node_symbol_str(c, "void");
-                    //}
-                }
-            };
-
-            const fn_proto = try c.a().create(ast.Node.FnProto);
-            fn_proto.* = ast.Node.FnProto{
-                .base = ast.Node{ .id = ast.Node.Id.FnProto },
-                .doc_comments = null,
-                .visib_token = null,
-                .fn_token = fn_tok,
-                .name_token = null,
-                .params = ast.Node.FnProto.ParamList.init(c.a()),
-                .return_type = ast.Node.FnProto.ReturnType{ .Explicit = return_type_node },
-                .var_args_token = var_args_tok,
-                .extern_export_inline_token = extern_tok,
-                .cc_token = cc_tok,
-                .async_attr = null,
-                .body_node = null,
-                .lib_name = null,
-                .align_expr = null,
-                .section_expr = null,
-            };
-            return &fn_proto.base;
-        },
-
+        .FunctionProto => return transFnProto(c, @ptrCast(*const ZigClangFunctionType, ty), source_loc, null, false),
         else => {
             const type_name = c.str(ZigClangType_getTypeClassName(ty));
             return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported type: '{}'", type_name);
@@ -297,6 +283,118 @@ fn transType(c: *Context, ty: *const ZigClangType, source_loc: ZigClangSourceLoc
     }
 }
 
+fn transFnProto(
+    c: *Context,
+    fn_proto_ty: *const ZigClangFunctionProtoType,
+    source_loc: ZigClangSourceLocation,
+    opt_fn_decl: ?*const ZigClangFunctionDecl,
+    fn_name: ?[]const u8,
+) !*ast.Node.FnProto {
+    const fn_ty = @ptrCast(*const ZigClangFunctionType, fn_proto_ty);
+    const rp = makeRestorePoint(c);
+    const cc = switch (ZigClangFunctionType_getCallConv(fn_ty)) {
+        .C => CallingConvention.C,
+        .X86StdCall => CallingConvention.Stdcall,
+        .X86FastCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 fastcall"),
+        .X86ThisCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 thiscall"),
+        .X86VectorCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 vectorcall"),
+        .X86Pascal => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 pascal"),
+        .Win64 => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: win64"),
+        .X86_64SysV => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 64sysv"),
+        .X86RegCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: x86 reg"),
+        .AAPCS => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: aapcs"),
+        .AAPCS_VFP => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: aapcs-vfp"),
+        .IntelOclBicc => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: intel_ocl_bicc"),
+        .SpirFunction => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: SPIR function"),
+        .OpenCLKernel => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: OpenCLKernel"),
+        .Swift => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: Swift"),
+        .PreserveMost => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: PreserveMost"),
+        .PreserveAll => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: PreserveAll"),
+        .AArch64VectorCall => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported calling convention: AArch64VectorCall"),
+    };
+
+    const is_var_args = ZigClangFunctionProtoType_isVariadic(fn_proto_ty);
+    const param_count: usize = ZigClangFunctionProtoType_getNumParams(fn_proto_ty);
+    var i: usize = 0;
+    while (i < param_count) : (i += 1) {
+        return revertAndWarn(rp, error.UnsupportedType, source_loc, "TODO: implement parameters for FunctionProto in transType");
+    }
+    // TODO check for always_inline attribute
+    // TODO check for align attribute
+
+    // extern fn name(...) T
+    const cc_tok = if (cc == .Stdcall) try appendToken(c, .Keyword_stdcallcc, "stdcallcc") else null;
+    const is_export = exp: {
+        const fn_decl = opt_fn_decl orelse break :exp false;
+        const has_body = ZigClangFunctionDecl_hasBody(fn_decl);
+        const storage_class = ZigClangFunctionDecl_getStorageClass(fn_decl);
+        break :exp switch (storage_class) {
+            .None => switch (c.mode) {
+                .import => false,
+                .translate => has_body,
+            },
+            .Extern, .Static => false,
+            .PrivateExtern => return revertAndWarn(rp, error.UnsupportedType, source_loc, "unsupported storage class: private extern"),
+            .Auto => unreachable, // Not legal on functions
+            .Register => unreachable, // Not legal on functions
+        };
+    };
+    const extern_export_inline_tok = if (is_export)
+        try appendToken(c, .Keyword_export, "export")
+    else if (cc == .C)
+        try appendToken(c, .Keyword_extern, "extern")
+    else
+        null;
+    const fn_tok = try appendToken(c, .Keyword_fn, "fn");
+    const name_tok = if (fn_name) |n| try appendToken(c, .Identifier, "{}", n) else null;
+    const lparen_tok = try appendToken(c, .LParen, "(");
+    const var_args_tok = if (is_var_args) try appendToken(c, .Ellipsis3, "...") else null;
+    const rparen_tok = try appendToken(c, .RParen, ")");
+
+    const return_type_node = blk: {
+        if (ZigClangFunctionType_getNoReturnAttr(fn_ty)) {
+            break :blk try appendIdentifier(c, "noreturn");
+        } else {
+            return revertAndWarn(rp, error.UnsupportedType, source_loc, "TODO: non-noreturn FunctionProto return type");
+            //proto_node->data.fn_proto.return_type = trans_qual_type(c,
+            //        ZigClangFunctionType_getReturnType(fn_ty), source_loc);
+            //if (proto_node->data.fn_proto.return_type == nullptr) {
+            //    emit_warning(c, source_loc, "unsupported function proto return type");
+            //    return nullptr;
+            //}
+            //// convert c_void to actual void (only for return type)
+            //// we do want to look at the AstNode instead of ZigClangQualType, because
+            //// if they do something like:
+            ////     typedef Foo void;
+            ////     void foo(void) -> Foo;
+            //// we want to keep the return type AST node.
+            //if (is_c_void_type(proto_node->data.fn_proto.return_type)) {
+            //    proto_node->data.fn_proto.return_type = trans_create_node_symbol_str(c, "void");
+            //}
+        }
+    };
+
+    const fn_proto = try c.a().create(ast.Node.FnProto);
+    fn_proto.* = ast.Node.FnProto{
+        .base = ast.Node{ .id = ast.Node.Id.FnProto },
+        .doc_comments = null,
+        .visib_token = null,
+        .fn_token = fn_tok,
+        .name_token = name_tok,
+        .params = ast.Node.FnProto.ParamList.init(c.a()),
+        .return_type = ast.Node.FnProto.ReturnType{ .Explicit = return_type_node },
+        .var_args_token = var_args_tok,
+        .extern_export_inline_token = extern_export_inline_tok,
+        .cc_token = cc_tok,
+        .async_attr = null,
+        .body_node = null,
+        .lib_name = null,
+        .align_expr = null,
+        .section_expr = null,
+    };
+    return fn_proto;
+}
+
 fn revertAndWarn(
     restore_point: RestorePoint,
     err: var,
test/tests.zig
@@ -903,6 +903,7 @@ pub const TranslateCContext = struct {
         sources: ArrayList(SourceFile),
         expected_lines: ArrayList([]const u8),
         allow_warnings: bool,
+        stage2: bool,
 
         const SourceFile = struct {
             filename: []const u8,
@@ -955,7 +956,8 @@ pub const TranslateCContext = struct {
             var zig_args = ArrayList([]const u8).init(b.allocator);
             zig_args.append(b.zig_exe) catch unreachable;
 
-            zig_args.append("translate-c") catch unreachable;
+            const translate_c_cmd = if (self.case.stage2) "translate-c-2" else "translate-c";
+            zig_args.append(translate_c_cmd) catch unreachable;
             zig_args.append(b.pathFromRoot(root_src)) catch unreachable;
 
             warn("Test {}/{} {}...", self.test_index + 1, self.context.test_index, self.name);
@@ -1052,6 +1054,7 @@ pub const TranslateCContext = struct {
             .sources = ArrayList(TestCase.SourceFile).init(self.b.allocator),
             .expected_lines = ArrayList([]const u8).init(self.b.allocator),
             .allow_warnings = allow_warnings,
+            .stage2 = false,
         };
 
         tc.addSourceFile(filename, source);
@@ -1072,6 +1075,26 @@ pub const TranslateCContext = struct {
         self.addCase(tc);
     }
 
+    pub fn add_both(self: *TranslateCContext, name: []const u8, source: []const u8, expected_lines: ...) void {
+        for ([]bool{ false, true }) |stage2| {
+            const tc = self.create(false, "source.c", name, source, expected_lines);
+            tc.stage2 = stage2;
+            self.addCase(tc);
+        }
+    }
+
+    pub fn add_2(self: *TranslateCContext, name: []const u8, source: []const u8, expected_lines: ...) void {
+        const tc = self.create(false, "source.c", name, source, expected_lines);
+        tc.stage2 = true;
+        self.addCase(tc);
+    }
+
+    pub fn addC_2(self: *TranslateCContext, name: []const u8, source: []const u8, expected_lines: ...) void {
+        const tc = self.create(false, "source.c", name, source, expected_lines);
+        tc.stage2 = true;
+        self.addCase(tc);
+    }
+
     pub fn addAllowWarnings(self: *TranslateCContext, name: []const u8, source: []const u8, expected_lines: ...) void {
         const tc = self.create(true, "source.h", name, source, expected_lines);
         self.addCase(tc);
@@ -1080,7 +1103,8 @@ pub const TranslateCContext = struct {
     pub fn addCase(self: *TranslateCContext, case: *const TestCase) void {
         const b = self.b;
 
-        const annotated_case_name = fmt.allocPrint(self.b.allocator, "translate-c {}", case.name) catch unreachable;
+        const translate_c_cmd = if (case.stage2) "translate-c-2" else "translate-c";
+        const annotated_case_name = fmt.allocPrint(self.b.allocator, "{} {}", translate_c_cmd, case.name) catch unreachable;
         if (self.test_filter) |filter| {
             if (mem.indexOf(u8, annotated_case_name, filter) == null) return;
         }
test/translate_c.zig
@@ -2,6 +2,12 @@ const tests = @import("tests.zig");
 const builtin = @import("builtin");
 
 pub fn addCases(cases: *tests.TranslateCContext) void {
+    cases.add_both("simple noreturn fn",
+        \\void __attribute__((noreturn)) foo(void);
+    ,
+        \\extern fn foo() noreturn;
+    );
+
     cases.add("macro with left shift",
         \\#define REDISMODULE_READ (1<<0)
     ,