Document the -Ov option, minor fix for gcc -Og

The -Ov option is useful but was undocumented.

Add an initialization to keep gcc from complaining at optimization
level -Og.

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

2 files changed, 9 insertions, 2 deletions

diff --git a/asm/nasm.c b/asm/nasm.c
index c6e82eaf..1c5a5fc5 100644
--- a/asm/nasm.c
+++ b/asm/nasm.c
@@ -1135,6 +1135,7 @@ static bool process_arg(char *p, char *q, int pass)
                     break;
                 }
 
+                olen = 0;       /* Placate gcc at lower optimization levels */
                 plen = strlen(p);
                 for (tx = textopts; tx->label; tx++) {
                     olen = strlen(tx->label);
@@ -1985,10 +1986,11 @@ static void help(const char xopt)
          "    -l listfile   write listing to a listfile\n\n"
          "    -Ipath        add a pathname to the include file path\n");
     printf
-        ("    -Olevel       optimize opcodes, immediates and branch offsets\n"
+        ("    -Oflags...    optimize opcodes, immediates and branch offsets\n"
          "       -O0        no optimization\n"
          "       -O1        minimal optimization\n"
          "       -Ox        multipass optimization (default)\n"
+         "       -Ov        display the number of passes executed at the end\n"
          "    -Pfile        pre-include a file (also --include)\n"
          "    -Dmacro[=str] pre-define a macro\n"
          "    -Umacro       undefine a macro\n"
diff --git a/doc/nasmdoc.src b/doc/nasmdoc.src
index bdec6b6e..ea6f10f2 100644
--- a/doc/nasmdoc.src
+++ b/doc/nasmdoc.src
@@ -746,7 +746,9 @@ with a \i{stub preprocessor} which does nothing.
 \S{opt-O} The \i\c{-O} Option: Specifying \i{Multipass Optimization}
 
 Using the \c{-O} option, you can tell NASM to carry out different
-levels of optimization.  The syntax is:
+levels of optimization. Multiple flags can be specified after the
+\c{-O} options, some of which can be combined in a single option,
+e.g. \c{-Oxv}.
 
 \b \c{-O0}: No optimization. All operands take their long forms,
         if a short form is not specified, except conditional jumps.
@@ -764,6 +766,9 @@ levels of optimization.  The syntax is:
         releases, the letter \c{x} may also be any number greater than
         one. This number has no effect on the actual number of passes.
 
+\b \c{-Ov}: At the end of assembly, print the number of passes
+        actually executed.
+
 The \c{-Ox} mode is recommended for most uses, and is the default
 since NASM 2.09.