feature/native-comp 41509d8 1/2: * Short eln filename hashes

[Andrea Corallo]

branch: feature/native-comp
commit 41509d873e8a05aa98133cb78f384e06e69779ab
Author: Andrea Corallo <akrl@sdf.org>
Commit: Andrea Corallo <akrl@sdf.org>

    * Short eln filename hashes
    
        * src/comp.c (HASH_LENGTH): New macro.
        (comp_hash_string, comp_hash_source_file): Trim the hash before
        returning.
---
 src/comp.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/comp.c b/src/comp.c
index b5adc3e..1b346f8 100644
--- a/src/comp.c
+++ b/src/comp.c
@@ -413,6 +413,9 @@ load_gccjit_if_necessary (bool mandatory)
 /* Increase this number to force a new Vcomp_abi_hash to be generated.  */
 #define ABI_VERSION "1"
 
+/* Length of the hashes used for eln file naming.  */
+#define HASH_LENGTH 8
+
 /* C symbols emitted for the load relocation mechanism.  */
 #define CURRENT_THREAD_RELOC_SYM "current_thread_reloc"
 #define PURE_RELOC_SYM "pure_reloc"
@@ -662,7 +665,7 @@ comp_hash_string (Lisp_Object string)
   md5_buffer (SSDATA (string), SCHARS (string), SSDATA (digest));
   hexbuf_digest (SSDATA (digest), SDATA (digest), MD5_DIGEST_SIZE);
 
-  return digest;
+  return Fsubstring (digest, Qnil, make_fixnum (HASH_LENGTH));
 }
 
 static Lisp_Object
@@ -688,7 +691,7 @@ comp_hash_source_file (Lisp_Object filename)
 
   hexbuf_digest (SSDATA (digest), SSDATA (digest), MD5_DIGEST_SIZE);
 
-  return digest;
+  return Fsubstring (digest, Qnil, make_fixnum (HASH_LENGTH));
 }
 
 /* Produce a key hashing Vcomp_subr_list.  */