Additional codegen.

CMakeLists.txt

@@ -371,6 +371,7 @@ endif()
 
 if(C3_WITH_LLVM)
     target_sources(c3c PRIVATE
+            src/compiler/c_codegen.c
             src/compiler/llvm_codegen.c
             src/compiler/llvm_codegen_debug_info.c
             src/compiler/llvm_codegen_expr.c

src/build/build.h

@@ -17,8 +17,9 @@
 
 typedef enum
 {
-	BACKEND_LLVM = 1,
-	BACKEND_TB = 2
+	BACKEND_LLVM = 0,
+	BACKEND_TB = 1,
+	BACKEND_C = 2,
 } CompilerBackend;
 
 typedef enum

src/build/build_internal.h

@@ -88,6 +88,12 @@ static const char *optlevels[4] = {
 	[OPTIMIZATION_AGGRESSIVE] = "max",
 };
 
+static const char *backends[3] = {
+		[BACKEND_LLVM] = "llvm",
+		[BACKEND_TB] = "tb",
+		[BACKEND_C] = "c",
+};
+
 static const char *backtrace_levels[2] = {
 	[SHOW_BACKTRACE_OFF] = "off",
 	[SHOW_BACKTRACE_ON] = "on",

src/build/build_options.c

@@ -654,6 +654,11 @@ static void parse_option(BuildOptions *options)
 				print_version();
 				exit_compiler(COMPILER_SUCCESS_EXIT);
 			}
+			if ((argopt = match_argopt("backend")))
+			{
+				options->backend = (CompilerBackend)parse_multi_option(argopt, 3, backends);
+				return;
+			}
 			if (match_longopt("run-once"))
 			{
 				options->run_once = true;

src/compiler/c_codegen_internal.h

@@ -0,0 +1 @@
+#include "codegen_internal.h"

src/compiler/compiler.c

@@ -468,6 +468,9 @@ void compiler_compile(void)
 
 	switch (compiler.build.backend)
 	{
+		case BACKEND_C:
+			gen_contexts = c_gen(modules, module_count);
+			error_exit("Unfinished C backend!");
 		case BACKEND_LLVM:
 #if LLVM_AVAILABLE
 			gen_contexts = llvm_gen(modules, module_count);

src/compiler/compiler_internal.h

@@ -439,6 +439,7 @@ typedef struct VarDecl_
 			{
 				// Variable
 				void *optional_ref;
+				int optional_id;
 				int tb_optional_reg;
 			};
 		};
@@ -613,6 +614,7 @@ typedef struct Decl_
 	union
 	{
 		void *backend_ref;
+		int backend_id;
 		int tb_register;
 		void *backend_value;
 		void *tb_symbol;
@@ -2120,6 +2122,7 @@ CastKind cast_to_bool_kind(Type *type);
 
 const char *llvm_codegen(void *context);
 const char *tilde_codegen(void *context);
+void **c_gen(Module** modules, unsigned module_count);
 void **llvm_gen(Module** modules, unsigned module_count);
 void **tilde_gen(Module** modules, unsigned module_count);
 

src/compiler/sema_decls.c

@@ -347,7 +347,6 @@ static bool sema_analyse_union_members(SemaContext *context, Decl *decl)
 		}
 		AlignSize member_alignment;
 		if (!sema_set_abi_alignment(context, member->type, &member_alignment)) return false;
-
 		if (!sema_check_struct_holes(context, decl, member)) return false;
 
 		ByteSize member_size = type_size(member->type);

src/compiler/semantic_analyser.c

@@ -208,15 +208,16 @@ static void register_generic_decls(CompilationUnit *unit, Decl **decls)
 		decl->unit = unit;
 		switch (decl->decl_kind)
 		{
-			case DECL_POISONED:
 			case DECL_ENUM_CONSTANT:
 			case DECL_FAULTVALUE:
-			case DECL_IMPORT:
-			case DECL_LABEL:
-			case DECL_CT_ASSERT:
-			case DECL_CT_ECHO:
 			case DECL_DECLARRAY:
 			case DECL_ERASED:
+			case DECL_LABEL:
+				UNREACHABLE
+			case DECL_POISONED:
+			case DECL_IMPORT:
+			case DECL_CT_ASSERT:
+			case DECL_CT_ECHO:
 			case DECL_FNTYPE:
 			case DECL_CT_INCLUDE:
 			case DECL_CT_EXEC: