codeview: Look up %include path when determining files to hash.

The hash calculation in calc_md5 tries to open the source file via
"filename" again. For %includes, this is the file name that was
specified in the %include directive, not the actual name of the file
that was opened by the preprocessor. In other words, this fails if the
include file is not in the current working directory.

Add pp_input_fopen that uses the preprocessor include path lookup
code to resolve a file name and open it, and use that in codeview.c.

Signed-off-by: Fabian Giesen <fabiang@radgametools.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

output/codeview.c

@@ -44,6 +44,7 @@
 
 #include "nasm.h"
 #include "nasmlib.h"
+#include "preproc.h"
 #include "saa.h"
 #include "output/outlib.h"
 #include "output/pecoff.h"
@@ -308,7 +309,7 @@ static void calc_md5(const char *const filename,
     FILE *f;
     MD5_CTX ctx;
 
-    f = fopen(filename, "r");
+    f = pp_input_fopen(filename);
     if (!f)
         goto done;
 

preproc.c

@@ -1559,6 +1559,23 @@ static FILE *inc_fopen(const char *file, StrList **dhead, StrList ***dtail,
     return NULL;
 }
 
+/*
+ * Opens an include or input file. Public version, for use by modules
+ * that get a file:lineno pair and need to look at the file again
+ * (e.g. the CodeView debug backend). Returns NULL on failure.
+ */
+FILE *pp_input_fopen(const char *filename)
+{
+    FILE *fp;
+    StrList *xsl = NULL;
+    StrList **xst = &xsl;
+
+    fp = inc_fopen(filename, &xsl, &xst, true);
+    if (xsl)
+        nasm_free(xsl);
+    return fp;
+}
+
 /*
  * Determine if we should warn on defining a single-line macro of
  * name `name', with `nparam' parameters. If nparam is 0 or -1, will

preproc.h

@@ -48,4 +48,7 @@ typedef const unsigned char macros_t;
 
 enum preproc_token pp_token_hash(const char *token);
 
+/* Opens an include file or input file. This uses the include path. */
+FILE *pp_input_fopen(const char *filename);
+
 #endif