From d6c26f9742eb2394536ec248c5de5be1ee2b30c6 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 11 Dec 2014 13:08:18 -0700
Subject: [PATCH] fix `PLT_DELAY_FROM_ZO`

Fetching bytecode from a previously read file was broken in the case
of a bytecode file with submodules.

Closes PR 14878
---
 racket/src/racket/src/read.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/racket/src/racket/src/read.c b/racket/src/racket/src/read.c
index 378dd36868..f6e6cd18ce 100644
--- a/racket/src/racket/src/read.c
+++ b/racket/src/racket/src/read.c
@@ -5416,7 +5416,7 @@ static Scheme_Object *read_compiled(Scheme_Object *port,
 {
   Scheme_Hash_Table *directory = NULL;
   Scheme_Object *result;
-  intptr_t size, shared_size, got, offset = 0, directory_count = 0;
+  intptr_t size, shared_size, got, offset, directory_count = 0;
   CPort *rp;
   intptr_t symtabsize;
   Scheme_Object **symtab;
@@ -5449,7 +5449,6 @@ static Scheme_Object *read_compiled(Scheme_Object *port,
                           "  expected version: %s",
                           (buf[0] ? buf : "???"), MZSCHEME_VERSION);
     }
-    offset += size + 1;
     
     mode = scheme_get_byte(port);
     if (mode == 'D') {
@@ -5473,10 +5472,8 @@ static Scheme_Object *read_compiled(Scheme_Object *port,
 
       /* Module hash code */
       got = scheme_get_bytes(port, 20, hash_code, 0);
-      offset += 20;
 
       symtabsize = read_simple_number_from_port(port);
-      offset += 4;
   
       /* Load table mapping symtab indices to stream positions: */
 
@@ -5495,8 +5492,6 @@ static Scheme_Object *read_compiled(Scheme_Object *port,
         scheme_read_err(port, NULL, -1, -1, -1, -1, 0, NULL,
                         "read (compiled): ill-formed code (bad table count: %" PRIdPTR " != %" PRIdPTR ")",
                         got, (all_short ? 2 : 4) * (symtabsize - 1));
-      offset += got;
-
       {
         /* This loop runs top to bottom, since sizeof(long) may be larger
            than the decoded integers (but it's never shorter) */
@@ -5527,8 +5522,6 @@ static Scheme_Object *read_compiled(Scheme_Object *port,
                         shared_size, size);
       }
 
-      offset += 8;
-
       rp = MALLOC_ONE_RT(CPort);
       SET_REQUIRED_TAG(rp->type = scheme_rt_compact_port);
       {
@@ -5542,6 +5535,7 @@ static Scheme_Object *read_compiled(Scheme_Object *port,
         scheme_tell_all(port, NULL, NULL, &base);
         rp->base = base;
       }
+      offset = SCHEME_INT_VAL(scheme_file_position(1, &port));
       rp->orig_port = port;
       rp->size = size;
       if ((got = scheme_get_bytes(port, size, (char *)rp->start, 0)) != size)
@@ -5590,7 +5584,7 @@ static Scheme_Object *read_compiled(Scheme_Object *port,
       } else {
         scheme_reserve_file_descriptor();
         rp->pos = shared_size; /* skip shared part */
-        delay_info->file_offset = offset + 2 + 1; /* +2 is for #~; +1 is ???? */
+        delay_info->file_offset = offset;
         delay_info->size = shared_size;
         delay_info->symtab_size = rp->symtab_size;
         delay_info->symtab = rp->symtab;