Add --debug-prefix-map option

Adds an option to remap file prefixes in output object files. This is
analogous to the "-fdebug-prefix-map" option in GCC, and allows files to
be built in a reproducible manner regardless of the build directory.

Signed-off-by: Joshua Watt <[email protected]>

Author: JPEWdev

asm/nasm.c

@@ -942,7 +942,8 @@ enum text_options {
     OPT_KEEP_ALL,
     OPT_NO_LINE,
     OPT_DEBUG,
-    OPT_REPRODUCIBLE
+    OPT_REPRODUCIBLE,
+    OPT_DEBUG_PREFIX_MAP
 };
 enum need_arg {
     ARG_NO,
@@ -975,6 +976,7 @@ static const struct textargs textopts[] = {
     {"no-line",  OPT_NO_LINE, ARG_NO, 0},
     {"debug",    OPT_DEBUG, ARG_MAYBE, 0},
     {"reproducible", OPT_REPRODUCIBLE, ARG_NO, 0},
+    {"debug-prefix-map", OPT_DEBUG_PREFIX_MAP, ARG_YES, 0},
     {NULL, OPT_BOGUS, ARG_NO, 0}
 };
 
@@ -1338,6 +1340,26 @@ static bool process_arg(char *p, char *q, int pass)
                 case OPT_REPRODUCIBLE:
                     reproducible = true;
                     break;
+                case OPT_DEBUG_PREFIX_MAP: {
+                    struct debug_prefix_list *d;
+                    char *c;
+                    c = strchr(param, '=');
+
+                    if (!c) {
+                        nasm_error(ERR_NONFATAL | ERR_NOFILE | ERR_USAGE,
+                                   "option `--%s' must be of the form `BASE=DEST'", p);
+                        break;
+                    }
+
+                    *c = '\0';
+                    d = nasm_malloc(sizeof(*d));
+                    d->next = debug_prefixes;
+                    d->base = nasm_strdup(param);
+                    d->dest = nasm_strdup(c + 1);
+                    debug_prefixes = d;
+                    *c = '=';
+                    }
+                    break;
                 case OPT_HELP:
                     help(stdout);
                     exit(0);
@@ -2296,6 +2318,8 @@ static void help(FILE *out)
         "   --lpostfix str append the given string to local symbols\n"
         "\n"
         "   --reproducible attempt to produce run-to-run identical output\n"
+        "   --debug-prefix-map base=dest\n"
+        "                  remap paths starting with 'base' to 'dest' in output files\n"
         "\n"
         "    -w+x          enable warning x (also -Wx)\n"
         "    -w-x          disable warning x (also -Wno-x)\n"

include/nasmlib.h

@@ -250,10 +250,19 @@ int64_t readstrnum(char *str, int length, bool *warn);
  */
 int32_t seg_alloc(void);
 
+struct debug_prefix_list {
+    struct debug_prefix_list *next;
+    char *base;
+    char *dest;
+};
+
+extern struct debug_prefix_list *debug_prefixes;
+
 /*
  * Add/replace or remove an extension to the end of a filename
  */
 const char *filename_set_extension(const char *inname, const char *extension);
+char *filename_debug_remap(char *dest, char const *inname, size_t len);
 
 /*
  * Utility macros...

nasm.txt

@@ -147,6 +147,10 @@ OPTIONS
 	Prepend or append (respectively) the given argument to all global or
 	extern variables.
 
+--debug-prefix-map 'BASE=DEST'::
+    Map file names beginning with 'BASE' to 'DEST' when encoding them in
+    output object files.
+
 SYNTAX
 ------
 This man page does not fully describe the syntax of *nasm*'s assembly language,

nasmlib/filename.c

@@ -39,6 +39,8 @@
 #include "nasmlib.h"
 #include "error.h"
 
+struct debug_prefix_list *debug_prefixes = NULL;
+
 /*
  * Add/modify a filename extension, assumed to be a period-delimited
  * field at the very end of the filename.  Returns a newly allocated
@@ -61,3 +63,21 @@ const char *filename_set_extension(const char *inname, const char *extension)
 
     return p;
 }
+
+char *filename_debug_remap(char *dest, char const *in, size_t len)
+{
+    struct debug_prefix_list *d;
+    size_t n;
+
+    for (d = debug_prefixes; d != NULL; d = d->next) {
+        n = strlen(d->base);
+        if (strncmp(in, d->base, n) == 0) {
+            strlcpy(dest, d->dest, len);
+            strlcat(dest, &in[n], len);
+            return dest;
+        }
+    }
+
+    strlcpy(dest, in, len);
+    return dest;
+}

output/outas86.c

@@ -110,6 +110,8 @@ static void as86_sect_write(struct Section *, const uint8_t *,
 
 static void as86_init(void)
 {
+    char filename[FILENAME_MAX];
+
     stext.data = saa_init(1L);
     stext.datalen = 0L;
     stext.head = stext.last = NULL;
@@ -131,7 +133,7 @@ static void as86_init(void)
     strslen = 0;
 
     /* as86 module name = input file minus extension */
-    as86_add_string(filename_set_extension(inname, ""));
+    as86_add_string(filename_debug_remap(filename, filename_set_extension(inname, ""), sizeof(filename)));
 }
 
 static void as86_cleanup(void)

output/outcoff.c

@@ -1072,14 +1072,14 @@ static void coff_symbol(char *name, int32_t strpos, int32_t value,
 
 static void coff_write_symbols(void)
 {
-    char filename[18];
+    char filename[19];
     uint32_t i;
 
     /*
      * The `.file' record, and the file name auxiliary record.
      */
     coff_symbol(".file", 0L, 0L, -2, 0, 0x67, 1);
-    strncpy(filename, inname, 18);
+    filename_debug_remap(filename, inname, 19);
     nasm_write(filename, 18, ofile);
 
     /*

output/outelf.c

@@ -553,7 +553,7 @@ static void elf_init(void)
     };
     const char * const *p;
 
-    strlcpy(elf_module, inname, sizeof(elf_module));
+    filename_debug_remap(elf_module, inname, sizeof(elf_module));
     sects = NULL;
     nsects = sectlen = 0;
     syms = saa_init((int32_t)sizeof(struct elf_symbol));

output/outieee.c

@@ -207,7 +207,7 @@ static void ieee_unqualified_name(char *, char *);
  */
 static void ieee_init(void)
 {
-    strlcpy(ieee_infile, inname, sizeof(ieee_infile));
+    filename_debug_remap(ieee_infile, inname, sizeof(ieee_infile));
     any_segs = false;
     fpubhead = NULL;
     fpubtail = &fpubhead;

output/outobj.c

@@ -644,7 +644,7 @@ static enum directive_result obj_directive(enum directive, char *);
 
 static void obj_init(void)
 {
-    strlcpy(obj_infile, inname, sizeof(obj_infile));
+    filename_debug_remap(obj_infile, inname, sizeof(obj_infile));
     first_seg = seg_alloc();
     any_segs = false;
     fpubhead = NULL;

stdlib/strlcat.c

@@ -29,7 +29,7 @@ size_t strlcat(char *dest, const char *src, size_t size)
     size_t n;
 
     /* find the NULL terminator in dest */
-    for (n = 0; i < size && dest[n] != '\0'; n++)
+    for (n = 0; n < size && dest[n] != '\0'; n++)
         ;
 
     /* destination was not NULL terminated. Return the initial size */