fix(codegen): prevent a huge class of name collisions

Author: radovanhorvat

docs/overview/16-ffi-c-interop.md

@@ -127,7 +127,35 @@ Extern structs without an init function cannot be default-constructed:
 f: io::File // error because io::File has no extern init function
 ```
 
-### 16.4 Native build requirements
+### 16.4 Generated C names and identifier restrictions
+
+Jik reserves identifiers beginning with `jik_`, `Jik`, and `JIK`. Do not use
+these prefixes for functions, types, globals, locals, fields, module aliases,
+or other Jik identifiers.
+
+Jik emits local variables and struct fields using their source spelling. To
+keep the generated C valid, names reserved by the C backend are also rejected
+in those positions. This includes C keywords, implementation-reserved names
+such as `__name` and `_Name`, and common names from the C headers included by
+Jik, such as `size_t`, `FILE`, `EOF`, and `NULL`.
+
+Generated C names are implementation details, not a stable C API. In
+particular, the compiler currently uses these namespaces:
+
+```text
+jik_src_*    symbols derived from Jik source declarations
+jik_vec_*    generated vector types and helpers
+jik_dict_*   generated dictionary types and helpers
+jik_opt_*    generated option types and helpers
+jik_*        compiler and runtime helpers
+Jik*         runtime C types
+```
+
+Embedded C is passed through unchanged and may introduce its own names or C
+macros. It must therefore avoid collisions with Jik-generated names and
+follow the normal C rules itself.
+
+### 16.5 Native build requirements
 
 An FFI module can declare the include paths, library paths, libraries, and runtime files needed to
 build programs that import it:

jiklib/bytes.jik

@@ -181,14 +181,14 @@ extern func jik_impl_bytes_to_bytes as
 typedef struct jik_impl_bytes_Bytes {
     uint8_t *data;
     size_t size;
-    JikRegion *region;
+    JikRegion *jik_region;
 } jik_impl_bytes_Bytes;
 
 typedef struct jik_impl_bytes_ByteBuf {
     uint8_t *data;
     size_t size;
     size_t capacity;
-    JikRegion *region;
+    JikRegion *jik_region;
 } jik_impl_bytes_ByteBuf;
 
 static int32_t
@@ -203,7 +203,7 @@ jik_impl_bytes_alloc_bytes(uint8_t *data, size_t size, JikRegion *a)
     jik_impl_bytes_Bytes *bytes = jik_region_alloc(a, sizeof(jik_impl_bytes_Bytes));
     bytes->data                = data;
     bytes->size                = size;
-    bytes->region              = a;
+    bytes->jik_region              = a;
     return bytes;
 }
 
@@ -229,7 +229,7 @@ jik_impl_bytes_string_from_raw(uint8_t *data, size_t size, JikRegion *a)
     s->data[size] = '\0';
     s->size       = size;
     s->capacity   = size;
-    s->region     = a;
+    s->jik_region     = a;
     return s;
 }
 
@@ -248,7 +248,7 @@ jik_impl_bytes_buf_reserve(jik_impl_bytes_ByteBuf *buf, size_t needed)
         new_cap *= 2;
     }
 
-    uint8_t *new_data = jik_region_alloc(buf->region, new_cap);
+    uint8_t *new_data = jik_region_alloc(buf->jik_region, new_cap);
     if (buf->data && buf->size > 0) {
         memcpy(new_data, buf->data, buf->size);
     }
@@ -355,7 +355,7 @@ jik_impl_bytes_buf_new(JikRegion *a)
     buf->data                  = jik_region_alloc(a, 16);
     buf->size                  = 0;
     buf->capacity              = 16;
-    buf->region                = a;
+    buf->jik_region                = a;
     return buf;
 }
 

jiklib/io.jik

@@ -93,7 +93,7 @@ typedef struct jik_impl_io_File {
     FILE *file;
     bool valid;
     JikString *mode;
-    JikRegion *region;
+    JikRegion *jik_region;
 } jik_impl_io_File;
 
 static bool
@@ -112,7 +112,7 @@ jik_impl_io_open(JikString *filepath, JikString *mode, JikRegion *a, JikError *e
         fh->file = NULL;
         fh->mode = jik_string_new(mode->data, a);
         fh->valid = false;
-        fh->region = a;
+        fh->jik_region = a;
         return fh;
     }
     jik_impl_io_File *fh = jik_region_alloc(a, sizeof(jik_impl_io_File));
@@ -122,7 +122,7 @@ jik_impl_io_open(JikString *filepath, JikString *mode, JikRegion *a, JikError *e
     if (!fh->valid) {
         jik_error_set(e, 1, "io::open: could not open file");
     }
-    fh->region = a;
+    fh->jik_region = a;
     return fh;
 }
 

jiklib/process.jik

@@ -69,9 +69,9 @@ extern func jik_impl_process_result_err as
 
 @embed{C_END}
 
-struct vec_JikString;
-JikString *vec_JikString_get(struct vec_JikString *v, size_t idx, char *dbg_info);
-size_t vec_JikString_size(struct vec_JikString *v, char *dbg_info);
+struct jik_vec_JikString;
+JikString *jik_vec_JikString_get(struct jik_vec_JikString *v, size_t idx, char *dbg_info);
+size_t jik_vec_JikString_size(struct jik_vec_JikString *v, char *dbg_info);
 struct jik_impl_bytes_Bytes;
 struct jik_impl_bytes_Bytes *
 jik_impl_bytes_from_raw_copy(uint8_t *data, size_t size, JikRegion *a);
@@ -234,14 +234,14 @@ jik_impl_process_append_windows_arg(JikCharBuffer *b, const char *arg, JikRegion
 
 static char *
 jik_impl_process_build_windows_command_line(
-    JikString *program, struct vec_JikString *args, JikRegion *r)
+    JikString *program, struct jik_vec_JikString *args, JikRegion *r)
 {
     JikCharBuffer *b = jik_char_buffer_new("", r);
     jik_impl_process_append_windows_arg(b, program->data, r);
 
-    size_t n = vec_JikString_size(args, "process::run args");
+    size_t n = jik_vec_JikString_size(args, "process::run args");
     for (size_t i = 0; i < n; i++) {
-        JikString *arg = vec_JikString_get(args, i, "process::run args");
+        JikString *arg = jik_vec_JikString_get(args, i, "process::run args");
         jik_char_buffer_append_char(b, ' ', r);
         jik_impl_process_append_windows_arg(b, arg->data, r);
     }
@@ -250,7 +250,7 @@ jik_impl_process_build_windows_command_line(
 }
 
 int32_t
-jik_impl_process_run(JikString *program, struct vec_JikString *args, JikError *e)
+jik_impl_process_run(JikString *program, struct jik_vec_JikString *args, JikError *e)
 {
     if (program->data[0] == '\0') {
         jik_impl_process_set_error(e, "process::run: invalid program");
@@ -358,7 +358,7 @@ jik_impl_process_create_pipe(HANDLE *read_handle, HANDLE *write_handle)
 }
 
 jik_impl_process_Result *
-jik_impl_process_capture_raw(JikString *program, struct vec_JikString *args, JikRegion *out_region, JikError *e)
+jik_impl_process_capture_raw(JikString *program, struct jik_vec_JikString *args, JikRegion *out_region, JikError *e)
 {
     if (program->data[0] == '\0') {
         jik_impl_process_set_error(e, "process::capture: invalid program");
@@ -501,17 +501,17 @@ jik_impl_process_close_if_open(int fd)
 }
 
 static char **
-jik_impl_process_build_argv(JikString *program, struct vec_JikString *args)
+jik_impl_process_build_argv(JikString *program, struct jik_vec_JikString *args)
 {
-    size_t n = vec_JikString_size(args, "process::run args");
+    size_t n = jik_vec_JikString_size(args, "process::run args");
     char **argv = malloc((n + 2) * sizeof(char *));
     if (!argv) {
         return NULL;
     }
 
     argv[0] = program->data;
     for (size_t i = 0; i < n; i++) {
-        JikString *arg = vec_JikString_get(args, i, "process::run args");
+        JikString *arg = jik_vec_JikString_get(args, i, "process::run args");
         argv[i + 1] = arg->data;
     }
     argv[n + 1] = NULL;
@@ -531,7 +531,7 @@ jik_impl_process_exit_code_from_status(int status)
 }
 
 int32_t
-jik_impl_process_run(JikString *program, struct vec_JikString *args, JikError *e)
+jik_impl_process_run(JikString *program, struct jik_vec_JikString *args, JikError *e)
 {
     if (program->data[0] == '\0') {
         jik_impl_process_set_error(e, "process::run: invalid program");
@@ -687,7 +687,7 @@ jik_impl_process_drain_pipes(int stdout_fd,
 }
 
 jik_impl_process_Result *
-jik_impl_process_capture_raw(JikString *program, struct vec_JikString *args, JikRegion *out_region, JikError *e)
+jik_impl_process_capture_raw(JikString *program, struct jik_vec_JikString *args, JikRegion *out_region, JikError *e)
 {
     if (program->data[0] == '\0') {
         jik_impl_process_set_error(e, "process::capture: invalid program");

jiklib/strbuf.jik

@@ -85,7 +85,7 @@ typedef struct jik_StrBuf {
     char *data;
     size_t size;
     size_t capacity;
-    JikRegion *region;
+    JikRegion *jik_region;
 } jik_StrBuf;
 
 jik_StrBuf *
@@ -98,7 +98,7 @@ jik_strbuf_new(JikString *from, JikRegion *a)
     sb->data[n] = '\0';
     sb->size = n;
     sb->capacity = n;
-    sb->region = a;
+    sb->jik_region = a;
     return sb;
 }
 
@@ -116,7 +116,7 @@ jik_strbuf_append(jik_StrBuf *sb, JikString *s)
             new_cap *= 2;
         }
 
-        char *new_data = jik_region_alloc(sb->region, new_cap + 1);
+        char *new_data = jik_region_alloc(sb->jik_region, new_cap + 1);
         if (sb->data && sb->size) {
             memcpy(new_data, sb->data, sb->size);
         }
@@ -137,7 +137,7 @@ jik_strbuf_append_char(jik_StrBuf *sb, char ch)
         while (new_cap + 1 < req) {
             new_cap *= 2;
         }
-        char *new_data = jik_region_alloc(sb->region, new_cap + 1);
+        char *new_data = jik_region_alloc(sb->jik_region, new_cap + 1);
         if (sb->data && sb->size) {
             memcpy(new_data, sb->data, sb->size);
         }