Use a hash to keep exactly one copy of each filename around

The old code for keeping track of source file name and line was
confused as hell about ownership of the strings, and it is pretty
clear we leaked that information all over the place.

Instead, use a hash table to keep a copy of each string as necessary,
and simply make references to a string pool that we keep until the end
of the assembly session.

This pool probably should be unified with the list of dependency
files, and so on, but that is for the development branch.

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

12 files changed, 180 insertions, 87 deletions

diff --git a/Makefile.in b/Makefile.in
index 4a5b3b08..1479a626 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -74,7 +74,7 @@ endif
 
 #-- Begin File Lists --#
 NASM =	nasm.$(O) nasmlib.$(O) ver.$(O) \
-	raa.$(O) saa.$(O) rbtree.$(O) \
+	raa.$(O) saa.$(O) rbtree.$(O) srcfile.$(O) \
 	realpath.$(O) \
 	float.$(O) insnsa.$(O) insnsb.$(O) \
 	directiv.$(O) \
@@ -444,6 +444,7 @@ regflags.$(O): regflags.c compiler.h config.h directiv.h insnsi.h nasm.h \
 regs.$(O): regs.c compiler.h config.h insnsi.h tables.h
 regvals.$(O): regvals.c compiler.h config.h insnsi.h tables.h
 saa.$(O): saa.c compiler.h config.h nasmlib.h saa.h
+srcfile.$(O): srcfile.c compiler.h config.h hashtbl.h nasmlib.h
 stdscan.$(O): stdscan.c compiler.h config.h directiv.h iflag.h iflaggen.h \
  insns.h insnsi.h nasm.h nasmlib.h opflags.h pptok.h preproc.h quote.h \
  regs.h stdscan.h tables.h tokens.h
diff --git a/Mkfiles/msvc.mak b/Mkfiles/msvc.mak
index 890ad43d..35dc9ead 100644
--- a/Mkfiles/msvc.mak
+++ b/Mkfiles/msvc.mak
@@ -47,7 +47,7 @@ X               = .exe
 #-- Begin File Lists --#
 # Edit in Makefile.in, not here!
 NASM =	nasm.$(O) nasmlib.$(O) ver.$(O) \
-	raa.$(O) saa.$(O) rbtree.$(O) \
+	raa.$(O) saa.$(O) rbtree.$(O) srcfile.$(O) \
 	realpath.$(O) \
 	float.$(O) insnsa.$(O) insnsb.$(O) \
 	directiv.$(O) \
@@ -350,6 +350,7 @@ regflags.$(O): regflags.c compiler.h directiv.h insnsi.h nasm.h nasmlib.h \
 regs.$(O): regs.c compiler.h insnsi.h tables.h
 regvals.$(O): regvals.c compiler.h insnsi.h tables.h
 saa.$(O): saa.c compiler.h nasmlib.h saa.h
+srcfile.$(O): srcfile.c compiler.h hashtbl.h nasmlib.h
 stdscan.$(O): stdscan.c compiler.h directiv.h iflag.h iflaggen.h insns.h \
  insnsi.h nasm.h nasmlib.h opflags.h pptok.h preproc.h quote.h regs.h \
  stdscan.h tables.h tokens.h
diff --git a/Mkfiles/netware.mak b/Mkfiles/netware.mak
index c3c8bf64..56509ee4 100644
--- a/Mkfiles/netware.mak
+++ b/Mkfiles/netware.mak
@@ -31,7 +31,7 @@ O = o
 #-- Begin File Lists --#
 # Edit in Makefile.in, not here!
 NASM =	nasm.o nasmlib.o ver.o \
-	raa.o saa.o rbtree.o \
+	raa.o saa.o rbtree.o srcfile.o \
 	realpath.o \
 	float.o insnsa.o insnsb.o \
 	directiv.o \
@@ -251,6 +251,7 @@ regflags.o: regflags.c compiler.h config.h directiv.h insnsi.h nasm.h \
 regs.o: regs.c compiler.h config.h insnsi.h tables.h
 regvals.o: regvals.c compiler.h config.h insnsi.h tables.h
 saa.o: saa.c compiler.h config.h nasmlib.h saa.h
+srcfile.o: srcfile.c compiler.h config.h hashtbl.h nasmlib.h
 stdscan.o: stdscan.c compiler.h config.h directiv.h iflag.h iflaggen.h \
  insns.h insnsi.h nasm.h nasmlib.h opflags.h pptok.h preproc.h quote.h \
  regs.h stdscan.h tables.h tokens.h
diff --git a/Mkfiles/openwcom.mak b/Mkfiles/openwcom.mak
index 7fb9ba51..3dffb117 100644
--- a/Mkfiles/openwcom.mak
+++ b/Mkfiles/openwcom.mak
@@ -47,7 +47,7 @@ X               = .exe
 #-- Begin File Lists --#
 # Edit in Makefile.in, not here!
 NASM =	nasm.$(O) nasmlib.$(O) ver.$(O) &
-	raa.$(O) saa.$(O) rbtree.$(O) &
+	raa.$(O) saa.$(O) rbtree.$(O) srcfile.$(O) &
 	realpath.$(O) &
 	float.$(O) insnsa.$(O) insnsb.$(O) &
 	directiv.$(O) &
@@ -399,6 +399,7 @@ regflags.$(O): regflags.c compiler.h config.h directiv.h insnsi.h nasm.h &
 regs.$(O): regs.c compiler.h config.h insnsi.h tables.h
 regvals.$(O): regvals.c compiler.h config.h insnsi.h tables.h
 saa.$(O): saa.c compiler.h config.h nasmlib.h saa.h
+srcfile.$(O): srcfile.c compiler.h config.h hashtbl.h nasmlib.h
 stdscan.$(O): stdscan.c compiler.h config.h directiv.h iflag.h iflaggen.h &
  insns.h insnsi.h nasm.h nasmlib.h opflags.h pptok.h preproc.h quote.h &
  regs.h stdscan.h tables.h tokens.h
diff --git a/Mkfiles/owlinux.mak b/Mkfiles/owlinux.mak
index b6ddad91..ad27d177 100644
--- a/Mkfiles/owlinux.mak
+++ b/Mkfiles/owlinux.mak
@@ -58,7 +58,7 @@ X               = .exe
 #-- Begin File Lists --#
 # Edit in Makefile.in, not here!
 NASM =	nasm.$(O) nasmlib.$(O) ver.$(O) \
-	raa.$(O) saa.$(O) rbtree.$(O) \
+	raa.$(O) saa.$(O) rbtree.$(O) srcfile.$(O) \
 	realpath.$(O) \
 	float.$(O) insnsa.$(O) insnsb.$(O) \
 	directiv.$(O) \
@@ -361,6 +361,7 @@ regflags.$(O): regflags.c compiler.h directiv.h insnsi.h nasm.h nasmlib.h \
 regs.$(O): regs.c compiler.h insnsi.h tables.h
 regvals.$(O): regvals.c compiler.h insnsi.h tables.h
 saa.$(O): saa.c compiler.h nasmlib.h saa.h
+srcfile.$(O): srcfile.c compiler.h hashtbl.h nasmlib.h
 stdscan.$(O): stdscan.c compiler.h directiv.h iflag.h iflaggen.h insns.h \
  insnsi.h nasm.h nasmlib.h opflags.h pptok.h preproc.h quote.h regs.h \
  stdscan.h tables.h tokens.h
diff --git a/assemble.c b/assemble.c
index 584bed72..b9e01e64 100644
--- a/assemble.c
+++ b/assemble.c
@@ -335,7 +335,7 @@ static void out(int64_t offset, int32_t segto, const void *data,
                 int32_t segment, int32_t wrt)
 {
     static int32_t lineno = 0;     /* static!!! */
-    static char *lnfname = NULL;
+    static const char *lnfname = NULL;
     uint8_t p[8];
     int asize = addrsize(type, size); 	    /* Address size in bytes */
     const int amax  = ofmt->maxbits >> 3; /* Maximum address size in bytes */
diff --git a/nasm.c b/nasm.c
index 3bf98af7..4df3c373 100644
--- a/nasm.c
+++ b/nasm.c
@@ -340,6 +340,7 @@ int main(int argc, char **argv)
     error_file = stderr;
 
     tolower_init();
+    src_init();
 
     offsets = raa_init();
     forwrefs = saa_init((int32_t)sizeof(struct forwrefinfo));
@@ -402,7 +403,7 @@ int main(int argc, char **argv)
             preproc->cleanup(0);
     } else if (operating_mode & OP_PREPROCESS) {
             char *line;
-            char *file_name = NULL;
+            const char *file_name = NULL;
             int32_t prior_linnum = 0;
             int lineinc = 0;
 
@@ -442,7 +443,6 @@ int main(int argc, char **argv)
                 nasm_fputs(line, ofile);
                 nasm_free(line);
             }
-            nasm_free(file_name);
             preproc->cleanup(0);
             if (ofile)
                 fclose(ofile);
@@ -482,9 +482,11 @@ int main(int argc, char **argv)
             ofmt->cleanup();
             cleanup_labels();
             fflush(ofile);
-            if (ferror(ofile))
+            if (ferror(ofile)) {
                 nasm_error(ERR_NONFATAL|ERR_NOFILE,
                            "write error on output file `%s'", outname);
+                terminate_after_phase = true;
+            }
         }
 
         if (ofile) {
@@ -505,6 +507,7 @@ int main(int argc, char **argv)
     saa_free(forwrefs);
     eval_cleanup();
     stdscan_cleanup();
+    src_free();
 
     return terminate_after_phase;
 }
@@ -1869,7 +1872,7 @@ static enum directives getkw(char **directive, char **value)
  */
 static void nasm_verror_gnu(int severity, const char *fmt, va_list ap)
 {
-    char *currentfile = NULL;
+    const char *currentfile = NULL;
     int32_t lineno = 0;
 
     if (is_suppressed_warning(severity))
@@ -1906,7 +1909,7 @@ static void nasm_verror_gnu(int severity, const char *fmt, va_list ap)
  */
 static void nasm_verror_vc(int severity, const char *fmt, va_list ap)
 {
-    char *currentfile = NULL;
+    const char *currentfile = NULL;
     int32_t lineno = 0;
 
     if (is_suppressed_warning(severity))
@@ -1918,7 +1921,6 @@ static void nasm_verror_vc(int severity, const char *fmt, va_list ap)
     if (!skip_this_pass(severity)) {
         if (currentfile) {
 	    fprintf(error_file, "%s(%"PRId32") : ", currentfile, lineno);
-	    nasm_free(currentfile);
 	} else {
 	    fputs("nasm: ", error_file);
 	}
diff --git a/nasmlib.c b/nasmlib.c
index 2bea64b3..f299f354 100644
--- a/nasmlib.c
+++ b/nasmlib.c
@@ -553,50 +553,6 @@ int bsii(const char *string, const char **array, int size)
     return -1;                  /* we haven't got it :( */
 }
 
-static char *file_name = NULL;
-static int32_t line_number = 0;
-
-char *src_set_fname(char *newname)
-{
-    char *oldname = file_name;
-    file_name = newname;
-    return oldname;
-}
-
-int32_t src_set_linnum(int32_t newline)
-{
-    int32_t oldline = line_number;
-    line_number = newline;
-    return oldline;
-}
-
-/* This returns a pointer, not a copy, to the current fname */
-const char *src_get_fname(void)
-{
-    return file_name;
-}
-
-int32_t src_get_linnum(void)
-{
-    return line_number;
-}
-
-int src_get(int32_t *xline, char **xname)
-{
-    if (!file_name || !*xname || strcmp(*xname, file_name)) {
-        nasm_free(*xname);
-        *xname = file_name ? nasm_strdup(file_name) : NULL;
-        *xline = line_number;
-        return -2;
-    }
-    if (*xline != line_number) {
-        int32_t tmp = line_number - *xline;
-        *xline = line_number;
-        return tmp;
-    }
-    return 0;
-}
-
 char *nasm_strcat(const char *one, const char *two)
 {
     char *rslt;
diff --git a/nasmlib.h b/nasmlib.h
index 08b2dc30..a4870d87 100644
--- a/nasmlib.h
+++ b/nasmlib.h
@@ -392,17 +392,24 @@ void fwriteaddr(uint64_t data, int size, FILE * fp);
 int bsi(const char *string, const char **array, int size);
 int bsii(const char *string, const char **array, int size);
 
-char *src_set_fname(char *newname);
+/*
+ * These functions are used to keep track of the source code file and name.
+ */
+void src_init(void);
+void src_free(void);
+const char *src_set_fname(const char *newname);
 const char *src_get_fname(void);
 int32_t src_set_linnum(int32_t newline);
 int32_t src_get_linnum(void);
+/* Can be used when there is no need for the old information */
+void src_set(int32_t line, const char *filename);
 /*
- * src_get may be used if you simply want to know the source file and line.
+ * src_get gets both the source file name and line.
  * It is also used if you maintain private status about the source location
  * It return 0 if the information was the same as the last time you
- * checked, -1 if the name changed and (new-old) if just the line changed.
+ * checked, -2 if the name changed and (new-old) if just the line changed.
  */
-int src_get(int32_t *xline, char **xname);
+int32_t src_get(int32_t *xline, const char **xname);
 
 char *nasm_strcat(const char *one, const char *two);
 
diff --git a/preproc-nop.c b/preproc-nop.c
index f8513a8a..56ef031d 100644
--- a/preproc-nop.c
+++ b/preproc-nop.c
@@ -60,8 +60,7 @@ static int32_t nop_lineinc;
 
 static void nop_reset(char *file, int pass, StrList **deplist)
 {
-    src_set_fname(nasm_strdup(file));
-    src_set_linnum(0);
+    src_set(0, file);
     nop_lineinc = 1;
     nop_fp = fopen(file, "r");
 
@@ -121,9 +120,9 @@ static char *nop_getline(void)
             int li;
             char *nm = nasm_malloc(strlen(buffer));
             if (sscanf(buffer + 5, "%"PRId32"+%d %s", &ln, &li, nm) == 3) {
-                nasm_free(src_set_fname(nm));
-                src_set_linnum(ln);
+                src_set(ln, nm);
                 nop_lineinc = li;
+                nasm_free(nm);
                 continue;
             }
             nasm_free(nm);
diff --git a/preproc.c b/preproc.c
index d2352808..0c9bf2d3 100644
--- a/preproc.c
+++ b/preproc.c
@@ -156,7 +156,7 @@ struct MMacro {
     int lineno;                 /* Current line number on expansion */
     uint64_t condcnt;           /* number of if blocks... */
 
-    char *fname;		/* File where defined */
+    const char *fname;		/* File where defined */
     int32_t xline;		/* First line in macro */
 };
 
@@ -271,7 +271,7 @@ struct Include {
     FILE *fp;
     Cond *conds;
     Line *expansion;
-    char *fname;
+    const char *fname;
     int lineno, lineinc;
     MMacro *mstk;       /* stack of active macros/reps */
 };
@@ -628,7 +628,6 @@ static void free_mmacro(MMacro * m)
     free_tlist(m->dlist);
     nasm_free(m->defaults);
     free_llist(m->expansion);
-    nasm_free(m->fname);
     nasm_free(m);
 }
 
@@ -2522,7 +2521,7 @@ static int do_directive(Token * tline)
             /* -MG given but file not found */
             nasm_free(inc);
         } else {
-            inc->fname = src_set_fname(nasm_strdup(p));
+            inc->fname = src_set_fname(p);
             inc->lineno = src_set_linnum(0);
             inc->lineinc = 1;
             inc->expansion = NULL;
@@ -3578,7 +3577,9 @@ issue_error:
         src_set_linnum(k);
         istk->lineinc = m;
         if (tline) {
-            nasm_free(src_set_fname(detoken(tline, false)));
+            char *fname = detoken(tline, false);
+            src_set_fname(fname);
+            nasm_free(fname);
         }
         free_tlist(origline);
         return DIRECTIVE_FOUND;
@@ -4135,12 +4136,10 @@ again:
                      */
                     if (!m->expansion) {
                         if (!strcmp("__FILE__", m->name)) {
-                            int32_t num = 0;
-                            char *file = NULL;
-                            src_get(&num, &file);
+                            const char *file = src_get_fname();
+                            /* nasm_free(tline->text); here? */
                             tline->text = nasm_quote(file, strlen(file));
                             tline->type = TOK_STRING;
-                            nasm_free(file);
                             continue;
                         }
                         if (!strcmp("__LINE__", m->name)) {
@@ -4855,8 +4854,7 @@ pp_reset(char *file, int apass, StrList **deplist)
     istk->mstk = NULL;
     istk->fp = fopen(file, "r");
     istk->fname = NULL;
-    src_set_fname(nasm_strdup(file));
-    src_set_linnum(0);
+    src_set(0, file);
     istk->lineinc = 1;
     if (!istk->fp)
 	nasm_fatal(ERR_NOFILE, "unable to open input file `%s'", file);
@@ -5032,10 +5030,8 @@ static char *pp_getline(void)
                                "expected `%%endif' before end of file");
                 }
                 /* only set line and file name if there's a next node */
-                if (i->next) {
-                    src_set_linnum(i->lineno);
-                    src_set_fname(nasm_strdup(i->fname));
-                }
+                if (i->next)
+                    src_set(i->lineno, i->fname);
                 istk = i->next;
                 lfmt->downlevel(LIST_INCLUDE);
                 nasm_free(i);
@@ -5146,12 +5142,11 @@ static void pp_cleanup(int pass)
         Include *i = istk;
         istk = istk->next;
         fclose(i->fp);
-        nasm_free(i->fname);
         nasm_free(i);
     }
     while (cstk)
         ctx_pop();
-    nasm_free(src_set_fname(NULL));
+    src_set_fname(NULL);
     if (pass == 0) {
         IncPath *i;
         free_llist(predef);
@@ -5269,8 +5264,7 @@ static void pp_list_one_macro(MMacro *m, int severity)
     pp_list_one_macro(m->next_active, severity);
 
     if (m->name && !m->nolist) {
-	src_set_linnum(m->xline + m->lineno);
-	src_set_fname(m->fname);
+	src_set(m->xline + m->lineno, m->fname);
 	nasm_error(severity, "... from macro `%s' defined here", m->name);
     }
 }
@@ -5281,13 +5275,11 @@ static void pp_error_list_macros(int severity)
     const char *saved_fname = NULL;
 
     severity |= ERR_PP_LISTMACRO | ERR_NO_SEVERITY;
-    saved_line = src_get_linnum();
-    saved_fname = src_get_fname();
+    src_get(&saved_line, &saved_fname);
 
     pp_list_one_macro(istk->mstk, severity);
 
-    src_set_fname((char *)saved_fname);
-    src_set_linnum(saved_line);
+    src_set(saved_line, saved_fname);
 }
 
 const struct preproc_ops nasmpp = {
diff --git a/srcfile.c b/srcfile.c
new file mode 100644
index 00000000..e84a8fb8
--- /dev/null
+++ b/srcfile.c
@@ -0,0 +1,132 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 1996-2016 The NASM Authors - All Rights Reserved
+ *   See the file AUTHORS included with the NASM distribution for
+ *   the specific copyright holders.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following
+ *   conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *
+ *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * srcfile.c - keep track of the current position in the input stream
+ */
+
+#include "compiler.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+
+#include "nasmlib.h"
+#include "hashtbl.h"
+
+static const char *file_name = NULL;
+static int32_t line_number = 0;
+
+static struct hash_table filename_hash;
+
+void src_init(void)
+{
+    hash_init(&filename_hash, HASH_MEDIUM);
+}
+
+void src_free(void)
+{
+    struct hash_tbl_node *iter = NULL;
+    void *dp;
+
+    while ((dp = hash_iterate(&filename_hash, &iter, NULL)) != NULL)
+        nasm_free(dp);
+
+    hash_free(&filename_hash);
+}
+
+/*
+ * Set the current filename, returning the old one.  The input
+ * filename is duplicated if needed.
+ */
+const char *src_set_fname(const char *newname)
+{
+    struct hash_insert hi;
+    const char *oldname;
+    void **dp;
+
+    if (newname) {
+        dp = hash_find(&filename_hash, newname, &hi);
+        if (dp) {
+            newname = (const char *)(*dp);
+        } else {
+            newname = nasm_strdup(newname);
+            hash_add(&hi, newname, (void *)newname);
+        }
+    }
+
+    oldname = file_name;
+    file_name = newname;
+    return oldname;
+}
+
+int32_t src_set_linnum(int32_t newline)
+{
+    int32_t oldline = line_number;
+    line_number = newline;
+    return oldline;
+}
+
+void src_set(int32_t line, const char *fname)
+{
+    src_set_fname(fname);
+    src_set_linnum(line);
+}
+
+const char *src_get_fname(void)
+{
+    return file_name;
+}
+
+int32_t src_get_linnum(void)
+{
+    return line_number;
+}
+
+int32_t src_get(int32_t *xline, const char **xname)
+{
+    const char *xn = *xname;
+    int32_t xl = *xline;
+
+    *xline = line_number;
+    *xname = file_name;
+
+    /* XXX: Is the strcmp() really needed here? */
+    if (!file_name || !xn || (xn != file_name && strcmp(xn, file_name)))
+        return -2;
+    else
+        return line_number - xl;
+}