From 1b939ecf3d0e937802431fee4c8e0a1954f2d113 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin (Intel)" <hpa@zytor.com>
Date: Wed, 15 Oct 2025 21:09:05 -0700
Subject: [PATCH] errors: add the ability to hold errors, not just warnings

Re-introduce ERR_HOLD, which means that an error is treated like a
warning except for the last pass, but unlike ERR_PASS2 the error
message *will* be issued if another error happens on the same pass, just
like warnings.

This will be used to improve error messages on instruction mismatch.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
---
 asm/error.c     |  8 ++++++++
 asm/nasm.c      | 19 +++++++++++--------
 asm/preproc.c   |  2 +-
 include/error.h |  1 +
 4 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/asm/error.c b/asm/error.c
index 0e17ffef..332f9254 100644
--- a/asm/error.c
+++ b/asm/error.c
@@ -85,6 +85,14 @@ void nasm_debug_(unsigned int level, const char *fmt, ...)
         nasm_do_error(ERR_DEBUG, LEVEL(level));
 }
 
+/*
+ * Convenience function for nasm_nonfatal(ERR_HOLD, ...)
+ */
+void nasm_holderr(const char *fmt, ...)
+{
+    nasm_do_error(ERR_NONFATAL, ERR_NONFATAL|ERR_HOLD);
+}
+
 fatal_func nasm_panic_from_macro(const char *func, const char *file, int line)
 {
     if (!func)
diff --git a/asm/nasm.c b/asm/nasm.c
index 8db100cf..5f7168f3 100644
--- a/asm/nasm.c
+++ b/asm/nasm.c
@@ -1870,13 +1870,12 @@ static errflags pure_func true_error_type(errflags severity)
 
     type = severity & ERR_MASK;
 
-    /* Promote warning to error? */
     if (type == ERR_WARNING) {
+        /* Promote warning to error? */
         uint8_t state = warning_state[WARN_IDX(severity)];
         if ((state & warn_is_err) == warn_is_err)
             type = ERR_NONFATAL;
     }
-
     return type;
 }
 
@@ -2125,6 +2124,7 @@ static void nasm_issue_error(struct nasm_errtext *et)
     const errflags severity  = et->severity;
     const errflags true_type = et->true_type;
     const struct src_location where = et->where;
+    bool buffer = true_type < ERR_NONFATAL || (severity & ERR_HOLD);
 
     if (severity & ERR_NO_SEVERITY)
         pfx = "";
@@ -2167,10 +2167,13 @@ static void nasm_issue_error(struct nasm_errtext *et)
             here = where.filename ? " here" : " in an unknown location";
         }
 
-        if (warn_list && true_type < ERR_NONFATAL) {
+        if (!warn_list)
+            buffer = false;
+
+        if (buffer) {
             /*
-             * Buffer up warnings until we either get an error
-             * or we are on the code-generation pass.
+             * Buffer up warnings and held errors until we either get
+             * an error or we are on the code-generation pass.
              */
             strlist_printf(warn_list, "%s%s%s%s%s%s%s",
                            file, linestr, errfmt->beforemsg,
@@ -2180,7 +2183,7 @@ static void nasm_issue_error(struct nasm_errtext *et)
              * Actually output an error.  If we have buffered
              * warnings, and this is a non-warning, output them now.
              */
-            if (true_type >= ERR_NONFATAL && warn_list) {
+            if (warn_list) {
                 strlist_write(warn_list, "\n", error_file);
                 strlist_free(&warn_list);
             }
@@ -2216,9 +2219,9 @@ static void nasm_issue_error(struct nasm_errtext *et)
     if (skip_this_pass(severity))
         goto done;
 
-    if (true_type >= ERR_FATAL)
+    if (true_type >= ERR_FATAL) {
         die_hard(true_type, severity);
-    else if (true_type >= ERR_NONFATAL) {
+    } else if (true_type >= ERR_NONFATAL && !buffer) {
         terminate_after_phase = true;
         errflags_never |= ERR_UNDEAD;
     }
diff --git a/asm/preproc.c b/asm/preproc.c
index cf028e7b..d0d65542 100644
--- a/asm/preproc.c
+++ b/asm/preproc.c
@@ -6464,7 +6464,7 @@ static SMacro *expand_one_smacro(Token ***tpp)
          */
         while (1) {
             if (!m) {
-                nasm_warn(WARN_PP_MACRO_PARAMS_SINGLE|ERR_HOLD,
+                nasm_warn(WARN_PP_MACRO_PARAMS_SINGLE,
                     "single-line macro `%s' exists, "
                     "but not taking %d parameter%s",
                     mname, nparam, (nparam == 1) ? "" : "s");
diff --git a/include/error.h b/include/error.h
index ae69fc84..22c5864a 100644
--- a/include/error.h
+++ b/include/error.h
@@ -28,6 +28,7 @@ void printf_func(2, 3) nasm_notef(errflags flags, const char *fmt, ...);
 void printf_func(2, 3) nasm_warn_(errflags flags, const char *fmt, ...);
 void printf_func(1, 2) nasm_nonfatal(const char *fmt, ...);
 void printf_func(2, 3) nasm_nonfatalf(errflags flags, const char *fmt, ...);
+void printf_func(1, 2) nasm_holderr(const char *fmt, ...);
 fatal_func printf_func(1, 2) nasm_fatal(const char *fmt, ...);
 fatal_func printf_func(2, 3) nasm_fatalf(errflags flags, const char *fmt, ...);
 fatal_func printf_func(1, 2) nasm_critical(const char *fmt, ...);