kit

commit 923c2ef63261ed6e24eee8c65c9ff7f5153345e5
parent ce021f13c697ea50f184ce1aeef44bef4b6e9a0e
Author: Ryan Sepassi <rsepassi@gmail.com>
Date:   Mon, 11 May 2026 17:18:07 -0700

Preprocess .S inputs in assembler driver

Diffstat:
M
driver/as.c
 | 
63
+++++++++++++++++++++++++++++++++++++++++++++++++++++++--------

1 file changed, 55 insertions(+), 8 deletions(-)
diff --git a/driver/as.c b/driver/as.c
@@ -1,11 +1,12 @@
 #include <stdint.h>
 
+#include "cflags.h"
 #include "driver.h"
 
 /* `cfree as` — standalone assembler. Reads a single text source, writes a
  * relocatable object via cfree_compile_obj_emit with the input tagged
- * CFREE_LANG_ASM. The accepted input is a GAS subset (AT&T syntax on x86);
- * see <cfree.h>. */
+ * CFREE_LANG_ASM. `.S` inputs are preprocessed first; `.s` inputs are not.
+ * The accepted input is a GAS subset (AT&T syntax on x86); see <cfree.h>. */
 
 #define AS_TOOL "as"
 
@@ -18,7 +19,7 @@ typedef struct AsOptions {
 
 static void as_usage(void) {
   driver_errf(AS_TOOL, "%s",
-              "usage: cfree as [-g] [-target TRIPLE] -o out.o input.s\n"
+              "usage: cfree as [-g] [-target TRIPLE] -o out.o input.{s,S}\n"
               "       cfree as --help    for full option reference");
 }
 
@@ -29,16 +30,22 @@ void driver_help_as(void) {
       "\n"
       "USAGE\n"
       "  cfree as [options] -o OUT.o INPUT.s\n"
+      "  cfree as [options] -o OUT.o INPUT.S\n"
       "\n"
       "DESCRIPTION\n"
       "  Reads a single text source written in a GAS subset (AT&T syntax on\n"
       "  x86, standard mnemonics on aarch64/riscv64) and writes a relocatable\n"
-      "  object via the same back-end the C compiler emits to. Exactly one\n"
-      "  positional input is required; -o is required.\n"
+      "  object via the same back-end the C compiler emits to. INPUT.S is run\n"
+      "  through the C preprocessor first; INPUT.s is assembled directly.\n"
+      "  Exactly one positional input is required; -o is required.\n"
       "\n"
       "OPTIONS\n"
       "  -o PATH           Output object path (required)\n"
       "  -g                Emit DWARF debug info from .file/.loc directives\n"
+      "  -I DIR, -IDIR     Add a user include directory for INPUT.S\n"
+      "  -isystem DIR      Add a system include directory for INPUT.S\n"
+      "  -D NAME[=VALUE]   Define a preprocessor macro for INPUT.S\n"
+      "  -U NAME           Undefine a preprocessor macro for INPUT.S\n"
       "  -target TRIPLE    Cross-assemble target. See `cfree cc --help` for "
       "the\n"
       "                    full list of recognized arches and OSes. Default:\n"
@@ -50,13 +57,19 @@ void driver_help_as(void) {
 }
 
 /* Returns 0 on success; non-zero on bad args (already reported). */
-static int as_parse(int argc, char** argv, AsOptions* o) {
+static int as_parse(int argc, char** argv, AsOptions* o, DriverEnv* env,
+                    DriverCflags* cf) {
   int i;
 
   o->target = driver_host_target();
 
   for (i = 1; i < argc; ++i) {
     const char* a = argv[i];
+    int r;
+
+    r = driver_cflags_try_consume(cf, env, AS_TOOL, argc, argv, &i);
+    if (r < 0) return 1;
+    if (r > 0) continue;
 
     if (driver_streq(a, "-g")) {
       o->debug_info = 1;
@@ -111,13 +124,19 @@ static int as_parse(int argc, char** argv, AsOptions* o) {
 int driver_as(int argc, char** argv) {
   DriverEnv env;
   AsOptions o = {0};
+  DriverCflags cf = {0};
   CfreeEnv cenv;
+  CfreePpOptions pp;
   CfreeCompiler* compiler = NULL;
   CfreeWriter* writer = NULL;
+  CfreeWriter* pp_writer = NULL;
   CfreeFileData src = {0};
   CfreeBytesInput input;
+  CfreeBytesInput asm_input;
   CfreeCompileOptions copts;
   CfreeCompileOptions zero = {0};
+  const uint8_t* pp_data;
+  size_t pp_len;
   int rc = 1;
   int loaded = 0;
 
@@ -128,10 +147,18 @@ int driver_as(int argc, char** argv) {
 
   driver_env_init(&env);
 
-  if (as_parse(argc, argv, &o) != 0) {
+  if (driver_cflags_init(&cf, &env, argc) != 0) {
+    driver_errf(AS_TOOL, "out of memory");
+    driver_env_fini(&env);
+    return 2;
+  }
+
+  if (as_parse(argc, argv, &o, &env, &cf) != 0) {
+    driver_cflags_fini(&cf, &env);
     driver_env_fini(&env);
     return 2;
   }
+  driver_cflags_fill_pp(&cf, &pp);
 
   cenv = driver_env_to_cfree(&env);
 
@@ -160,13 +187,33 @@ int driver_as(int argc, char** argv) {
   input.data = src.data;
   input.len = src.size;
   input.lang = CFREE_LANG_ASM;
+  asm_input = input;
+
+  if (driver_has_suffix(o.source, ".S")) {
+    pp_writer = cfree_writer_mem(cenv.heap);
+    if (!pp_writer) {
+      driver_errf(AS_TOOL, "out of memory");
+      goto out;
+    }
+    if (cfree_preprocess(compiler, &pp, &input, pp_writer) != 0) goto out;
+    if (cfree_writer_error(pp_writer)) {
+      driver_errf(AS_TOOL, "failed to preprocess: %s", o.source);
+      goto out;
+    }
+    pp_data = cfree_writer_mem_bytes(pp_writer, &pp_len);
+    asm_input.data = pp_data;
+    asm_input.len = pp_len;
+    asm_input.lang = CFREE_LANG_ASM;
+  }
 
-  rc = cfree_compile_obj_emit(compiler, &copts, &input, writer);
+  rc = cfree_compile_obj_emit(compiler, &copts, &asm_input, writer);
 
 out:
   if (compiler) driver_compiler_free(compiler);
+  if (pp_writer) cfree_writer_close(pp_writer);
   if (writer) cfree_writer_close(writer);
   if (loaded) cenv.file_io->release(cenv.file_io->user, &src);
+  driver_cflags_fini(&cf, &env);
   driver_env_fini(&env);
   return rc;
 }