(#481) Treat variable shadowing warning as error if requested

bang/nobuild.c

@@ -24,7 +24,8 @@
                    PATH("..", "basm", "src", "verifier.c")
 #define BANG_UNITS PATH("src", "bang_compiler.c"), \
                    PATH("src", "bang_lexer.c"), \
-                   PATH("src", "bang_parser.c")
+                   PATH("src", "bang_parser.c"), \
+                   PATH("src", "bang_diag.c")
 #define UNITS BM_UNITS, COMMON_UNITS, BASM_UNITS, BANG_UNITS
 #define LIBS "-lm"
 

bang/src/bang.c

@@ -11,6 +11,8 @@
 
 #define BANG_DEFAULT_STACK_SIZE 4096
 
+// TODO(#483): move intersecting `bang run` and `bang build` flags to `bang`
+
 static void build_usage(FILE *stream)
 {
     fprintf(stream, "Usage: bang build [OPTIONS] <input.bang>\n");
@@ -19,6 +21,7 @@ static void build_usage(FILE *stream)
     fprintf(stream, "    -t <target>    Output target. Default is `bm`.\n");
     fprintf(stream, "                   Provide `list` to get the list of all available targets.\n");
     fprintf(stream, "    -s <bytes>     Local variables stack size in bytes. (default %zu)\n", (size_t) BANG_DEFAULT_STACK_SIZE);
+    fprintf(stream, "    -werror        Treat warnings as errors\n");
     fprintf(stream, "    -h             Print this help to stdout\n");
 }
 
@@ -53,6 +56,7 @@ static void run_usage(FILE *stream)
     fprintf(stream, "OPTIONS:\n");
     fprintf(stream, "    -t             Enable trace mode\n");
     fprintf(stream, "    -s <bytes>     Local variables stack size in bytes. (default %zu)\n", (size_t) BANG_DEFAULT_STACK_SIZE);
+    fprintf(stream, "    -werror        Treat warnings as errors\n");
     fprintf(stream, "    -h             Print this help to stdout\n");
 }
 
@@ -90,7 +94,14 @@ static void run_subcommand(int argc, char **argv)
                         stack_size_cstr);
                 exit(1);
             }
+        } else if (strcmp(flag, "-werror") == 0) {
+            bang.warnings_as_errors = true;
         } else {
+            if (input_file_path != NULL) {
+                fprintf(stderr, "ERROR: input file path is already specified as `%s`. Multiple file paths are not supported yet\n", input_file_path);
+                exit(1);
+            }
+
             input_file_path = flag;
         }
     }
@@ -231,6 +242,11 @@ static void build_subcommand(int argc, char **argv)
             build_usage(stdout);
             exit(0);
         } else {
+            if (input_file_path != NULL) {
+                fprintf(stderr, "ERROR: input file path is already specified as `%s`. Multiple file paths are not supported yet\n", input_file_path);
+                exit(1);
+            }
+
             input_file_path = flag;
         }
     }

bang/src/bang_compiler.c

@@ -719,14 +719,17 @@ void compile_var_def_into_basm(Bang *bang, Basm *basm, Bang_Var_Def var_def, Ban
 
     // Shadowed Var Warning
     {
-        // TODO(#481): bang has no option to treat warnings as errors
         Compiled_Var *shadowed_var = bang_get_compiled_var_by_name(bang, var_def.name);
         if (shadowed_var) {
-            fprintf(stderr, Bang_Loc_Fmt": WARNING: variable `"SV_Fmt"` is shadowing another variable with the same name\n",
-                    Bang_Loc_Arg(var_def.loc),
-                    SV_Arg(var_def.name));
-            fprintf(stderr, Bang_Loc_Fmt": NOTE: the shadowed variable is located here\n",
-                    Bang_Loc_Arg(shadowed_var->def.loc));
+            bang_diag_msg(var_def.loc, bang->warnings_as_errors ? BANG_DIAG_ERROR : BANG_DIAG_WARNING,
+                          "variable `"SV_Fmt"` is shadowing another variable with the same name",
+                          SV_Arg(var_def.name));
+            bang_diag_msg(shadowed_var->def.loc, BANG_DIAG_NOTE,
+                          "the shadowed variable is located here");
+
+            if (bang->warnings_as_errors) {
+                exit(1);
+            }
         }
     }
 

bang/src/bang_compiler.h

@@ -79,6 +79,8 @@ typedef struct {
     size_t procs_count;
 
     Bang_Loc entry_loc;
+
+    bool warnings_as_errors;
 } Bang;
 
 Compiled_Var *bang_get_compiled_var_by_name(Bang *bang, String_View name);

bang/src/bang_diag.c

@@ -0,0 +1,32 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include "./bang_diag.h"
+
+const char *bang_diag_level_label(Bang_Diag_Level level)
+{
+    switch (level) {
+    case BANG_DIAG_NOTE:
+        return "NOTE";
+    case BANG_DIAG_WARNING:
+        return "WARNING";
+    case BANG_DIAG_ERROR:
+        return "ERROR";
+    default:
+        assert(false && "unreachable");
+        exit(1);
+    }
+}
+
+void bang_diag_msg(Bang_Loc loc, Bang_Diag_Level level, const char *fmt, ...)
+{
+    fprintf(stderr, Bang_Loc_Fmt": %s: ", Bang_Loc_Arg(loc), bang_diag_level_label(level));
+
+    va_list args;
+    va_start(args, fmt);
+    vfprintf(stderr, fmt, args);
+    va_end(args);
+
+    fprintf(stderr, "\n");
+}

bang/src/bang_diag.h

@@ -0,0 +1,31 @@
+#ifndef BANG_DIAG_H_
+#define BANG_DIAG_H_
+
+#include <stdlib.h>
+
+#if defined(__GNUC__) || defined(__clang__)
+// https://gcc.gnu.org/onlinedocs/gcc-4.7.2/gcc/Function-Attributes.html
+#define BANG_PRINTF_FORMAT(STRING_INDEX, FIRST_TO_CHECK) __attribute__ ((format (printf, STRING_INDEX, FIRST_TO_CHECK)))
+#else
+#define BANG_PRINTF_FORMAT(STRING_INDEX, FIRST_TO_CHECK)
+#endif
+
+typedef struct {
+    size_t row;
+    size_t col;
+    const char *file_path;
+} Bang_Loc;
+
+#define Bang_Loc_Fmt "%s:%zu:%zu"
+#define Bang_Loc_Arg(loc) (loc).file_path, (loc).row, (loc).col
+
+typedef enum {
+    BANG_DIAG_NOTE,
+    BANG_DIAG_WARNING,
+    BANG_DIAG_ERROR,
+} Bang_Diag_Level;
+
+const char *bang_diag_level_label(Bang_Diag_Level level);
+void bang_diag_msg(Bang_Loc loc, Bang_Diag_Level level, const char *fmt, ...) BANG_PRINTF_FORMAT(3, 4);
+
+#endif // BANG_DIAG_H_

bang/src/bang_lexer.h

@@ -4,6 +4,7 @@
 #include <stdlib.h>
 
 #include "./sv.h"
+#include "./bang_diag.h"
 
 typedef enum {
     BANG_TOKEN_KIND_NAME = 0,
@@ -31,15 +32,6 @@ typedef enum {
 
 const char *bang_token_kind_name(Bang_Token_Kind kind);
 
-typedef struct {
-    size_t row;
-    size_t col;
-    const char *file_path;
-} Bang_Loc;
-
-#define Bang_Loc_Fmt "%s:%zu:%zu"
-#define Bang_Loc_Arg(loc) (loc).file_path, (loc).row, (loc).col
-
 typedef struct {
     Bang_Token_Kind kind;
     String_View text;