error: new flag ERR_HERE

ERR_HERE is used to mark messages of the form "... here" so that we
can emit sane output to the list file with filename and line number,
instead of a nonsensical "here" which could point almost anywhere.

This patch contains some changes from the one in the master branch to
make the code cleaner.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

6 files changed, 87 insertions, 71 deletions

diff --git a/asm/labels.c b/asm/labels.c
index d0904ad3..a3ed0066 100644
--- a/asm/labels.c
+++ b/asm/labels.c
@@ -506,17 +506,18 @@ void define_label(const char *label, int32_t segment,
             nasm_error(ERR_NONFATAL,
                        "label `%s' inconsistently redefined",
                        lptr->defn.label);
-            noteflags = ERR_NOTE;
+            noteflags = ERR_NOTE|ERR_HERE;
         } else {
             nasm_error(ERR_WARNING|WARN_LABEL_REDEF|ERR_PASS2,
                        "label `%s' redefined to an identical value",
                        lptr->defn.label);
-            noteflags = ERR_NOTE|WARN_LABEL_REDEF|ERR_PASS2;
+            noteflags = ERR_NOTE|ERR_HERE|WARN_LABEL_REDEF|ERR_PASS2;
         }
 
         src_get(&saved_line, &saved_fname);
         src_set(lptr->defn.def_line, lptr->defn.def_file);
-        nasm_error(noteflags, "label `%s' originally defined here", lptr->defn.label);
+        nasm_error(noteflags, "label `%s' originally defined",
+                   lptr->defn.label);
         src_set(saved_line, saved_fname);
     } else if (changed && pass0 > 1 && lptr->defn.type != LBL_SPECIAL) {
         /*
diff --git a/asm/listing.c b/asm/listing.c
index fe7c5e92..4d753dbd 100644
--- a/asm/listing.c
+++ b/asm/listing.c
@@ -331,27 +331,27 @@ static void list_downlevel(int type)
     }
 }
 
-static void list_error(int severity, const char *pfx, const char *msg)
+static void list_error(int severity, const char *fmt, ...)
 {
-    size_t l1, l2;
     struct list_error *le;
-    char *p;
+    va_list ap;
+    int len;
 
     if (!listfp)
 	return;
 
-    l1 = strlen(pfx);
-    l2 = strlen(msg);
+    va_start(ap, fmt);
+    len = vsnprintf(NULL, 0, fmt, ap);
+    va_end(ap);
 
     /* sizeof(*le) already accounts for the final NULL */
-    le = nasm_malloc(sizeof(*le) + l1 + l2);
+    le = nasm_malloc(sizeof(*le) + len);
 
-    le->next = NULL;
-    p = le->str;
-    p = mempcpy(p, pfx, l1);
-    p = mempcpy(p, msg, l2);
-    *p = '\0';
+    va_start(ap, fmt);
+    vsnprintf(le->str, len+1, fmt, ap);
+    va_end(ap);
 
+    le->next = NULL;
     *listerr_tail = le;
     listerr_tail = &le->next;
 
diff --git a/asm/listing.h b/asm/listing.h
index df88e8a8..f3ddb0e0 100644
--- a/asm/listing.h
+++ b/asm/listing.h
@@ -96,7 +96,7 @@ struct lfmt {
     /*
      * Called on a warning or error, with the error message.
      */
-    void (*error)(int severity, const char *pfx, const char *msg);
+    void printf_func(2, 3) (*error)(int severity, const char *fmt, ...);
 
     /*
      * Update the current offset.  Used to give the listing generator
diff --git a/asm/nasm.c b/asm/nasm.c
index 100e4b9c..ddc3404e 100644
--- a/asm/nasm.c
+++ b/asm/nasm.c
@@ -1768,21 +1768,35 @@ static bool skip_this_pass(int severity)
  */
 static bool is_suppressed(int severity)
 {
+    if ((severity & ERR_MASK) >= ERR_FATAL)
+        return false;           /* Fatal errors can never be suppressed */
+
     return !(warning_state[warn_index(severity)] & WARN_ST_ENABLED);
 }
 
 /**
- * check if we have a warning that should be promoted to an error
+ * Return the true error type (the ERR_MASK part) of the given
+ * severity, accounting for warnings that may need to be promoted to
+ * error.
  *
  * @param severity the severity of the warning or error
- * @return true if we should promote to error
+ * @return true if we should error out
  */
-static bool warning_is_error(int severity)
+static int true_error_type(int severity)
 {
-    if ((severity & ERR_MASK) != ERR_WARNING)
-        return false;           /* Other message types  */
+    const uint8_t warn_is_err = WARN_ST_ENABLED|WARN_ST_ERROR;
+    int type;
+
+    type = severity & ERR_MASK;
+
+    /* Promote warning to error? */
+    if (type == ERR_WARNING) {
+        uint8_t state = warning_state[warn_index(severity)];
+        if ((state & warn_is_err) == warn_is_err)
+            type = ERR_NONFATAL;
+    }
 
-    return !!(warning_state[warn_index(severity)] & WARN_ST_ERROR);
+    return type;
 }
 
 /**
@@ -1798,10 +1812,17 @@ static bool warning_is_error(int severity)
 static void nasm_verror_asm(int severity, const char *fmt, va_list args)
 {
     char msg[1024];
+    char warnsuf[64];
+    char linestr[64];
     const char *pfx;
-    bool warn_is_err = warning_is_error(severity);
+    int spec_type = severity & ERR_MASK; /* type originally specified */
+    int true_type = true_error_type(severity);
     const char *currentfile = NULL;
     int32_t lineno = 0;
+    static const char * const pfx_table[ERR_MASK+1] = {
+        "debug: ", "note: ", "warning: ", "error: ",
+        "", "", "fatal: ", "panic: "
+    };
 
     if (is_suppressed(severity))
         return;
@@ -1816,53 +1837,38 @@ static void nasm_verror_asm(int severity, const char *fmt, va_list args)
             lineno = 0;
         }
     }
-    if (!currentfile)
-        currentfile = "nasm";
 
-    switch (severity & (ERR_MASK|ERR_NO_SEVERITY)) {
-    case ERR_NOTE:
-        pfx = "note: ";
-        break;
-    case ERR_WARNING:
-        if (!warn_is_err) {
-            pfx = "warning: ";
-            break;
-        }
-        /* fall through */
-    case ERR_NONFATAL:
-        pfx = "error: ";
-        break;
-    case ERR_FATAL:
-        pfx = "fatal: ";
-        break;
-    case ERR_PANIC:
-        pfx = "panic: ";
-        break;
-    case ERR_DEBUG:
-        pfx = "debug: ";
-        break;
-    default:
+    /*
+     * For a debug/warning/note event, if ERR_HERE is set don't
+     * output anything if there is no current filename available
+     */
+    if (!currentfile && (severity & ERR_HERE) && true_type <= ERR_WARNING)
+        return;
+
+    if (severity & ERR_NO_SEVERITY)
         pfx = "";
-        break;
+    else
+        pfx = pfx_table[true_type];
+
+    vsnprintf(msg, sizeof msg, fmt, args);
+    *warnsuf = 0;
+    if (spec_type == ERR_WARNING) {
+	snprintf(warnsuf, sizeof warnsuf, " [-w+%s%s]",
+                 true_type ? "error=" : "",
+                 warnings[warn_index(severity)].name);
     }
 
-    vsnprintf(msg, sizeof msg - 64, fmt, args);
-    if ((severity & ERR_MASK) == ERR_WARNING && !is_suppressed(severity)) {
-        char *p = strchr(msg, '\0');
-	snprintf(p, 64, " [-w+%s%s]",
-                 warn_is_err ? "error=" : "",
-                 warnings[warn_index(severity)].name);
+    *linestr = 0;
+    if (lineno) {
+        snprintf(linestr, sizeof linestr, "%s%"PRId32"%s",
+                 errfmt->beforeline, lineno, errfmt->afterline);
     }
 
     if (!skip_this_pass(severity)) {
-        if (!lineno) {
-            fprintf(error_file, "%s%s%s%s\n",
-                    currentfile, errfmt->beforemsg, pfx, msg);
-        } else {
-            fprintf(error_file, "%s%s%"PRId32"%s%s%s%s\n",
-                    currentfile, errfmt->beforeline, lineno,
-                    errfmt->afterline, errfmt->beforemsg, pfx, msg);
-        }
+        fprintf(error_file, "%s%s%s%s%s%s%s\n",
+                currentfile ? currentfile : "nasm",
+                linestr, errfmt->beforemsg, pfx, msg,
+                (severity & ERR_HERE) ? " here" : "", warnsuf);
     }
 
     /* Are we recursing from error_list_macros? */
@@ -1873,7 +1879,19 @@ static void nasm_verror_asm(int severity, const char *fmt, va_list args)
      * Don't suppress this with skip_this_pass(), or we don't get
      * pass1 or preprocessor warnings in the list file
      */
-    lfmt->error(severity, pfx, msg);
+    if (severity & ERR_HERE) {
+        if (lineno)
+            lfmt->error(severity, "%s%s at %s:%"PRId32"%s",
+                        pfx, msg, currentfile, lineno, warnsuf);
+        else if (currentfile)
+            lfmt->error(severity, "%s%s in file %s%s",
+                        pfx, msg, currentfile, warnsuf);
+        else
+            lfmt->error(severity, "%s%s in unknown location%s",
+                        pfx, msg, warnsuf);
+    } else {
+        lfmt->error(severity, "%s%s%s", pfx, msg, warnsuf);
+    }
 
     if (skip_this_pass(severity))
         return;
@@ -1883,15 +1901,11 @@ static void nasm_verror_asm(int severity, const char *fmt, va_list args)
 
     preproc->error_list_macros(severity);
 
-    switch (severity & ERR_MASK) {
+    switch (true_type) {
     case ERR_NOTE:
     case ERR_DEBUG:
-        /* no further action, by definition */
-        break;
     case ERR_WARNING:
-        /* Treat warnings as errors */
-        if (warning_is_error(severity))
-            terminate_after_phase = true;
+        /* no further action, by definition */
         break;
     case ERR_NONFATAL:
         terminate_after_phase = true;
diff --git a/asm/preproc.c b/asm/preproc.c
index 3b8de02b..b134414a 100644
--- a/asm/preproc.c
+++ b/asm/preproc.c
@@ -5451,7 +5451,7 @@ static void pp_list_one_macro(MMacro *m, int severity)
 
     if (m->name && !m->nolist) {
 	src_set(m->xline + m->lineno, m->fname);
-	nasm_error(severity, "... from macro `%s' defined here", m->name);
+	nasm_error(severity, "... from macro `%s' defined", m->name);
     }
 }
 
@@ -5460,7 +5460,7 @@ static void pp_error_list_macros(int severity)
     int32_t saved_line;
     const char *saved_fname = NULL;
 
-    severity |= ERR_PP_LISTMACRO | ERR_NO_SEVERITY;
+    severity |= ERR_PP_LISTMACRO | ERR_NO_SEVERITY | ERR_HERE;
     src_get(&saved_line, &saved_fname);
 
     if (istk)
diff --git a/include/error.h b/include/error.h
index d2f04f4c..5a676e67 100644
--- a/include/error.h
+++ b/include/error.h
@@ -72,6 +72,7 @@ static inline vefunc nasm_set_verror(vefunc ve)
                                          * and dump core for reference */
 #define ERR_MASK        0x00000007      /* mask off the above codes */
 #define ERR_NOFILE      0x00000010      /* don't give source file name/line */
+#define ERR_HERE	0x00000020      /* point to a specific source location */
 #define ERR_USAGE       0x00000040      /* print a usage message */
 #define ERR_PASS1       0x00000080      /* only print this error on pass 1 */
 #define ERR_PASS2       0x00000100      /* only print this error on pass 2 */