From 5263d10ba361cf0666cb6b2730132a018ba67bd6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Fri, 17 Feb 2017 12:03:08 +0100
Subject: Teach make_preload to handle the new 'AtU8' chunk

26b59dfe67 introduced the new 'AtU8' chunk to support
Unicode atoms.

make_preload strips the pre-loaded BEAM files so that they
only contain essential chunks. It expects to find the old
'Atom' chunk.

Teach make_preload to read the new 'AtU8' chunk instead of the old
chunk. Also produce a nice error message if someone by mistake
compiles the pre-loaded modules with an OTP 19 compiler.
---
 erts/emulator/utils/make_preload | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

(limited to 'erts/emulator')

diff --git a/erts/emulator/utils/make_preload b/erts/emulator/utils/make_preload
index 8b629d9517..bcb2e42614 100755
--- a/erts/emulator/utils/make_preload
+++ b/erts/emulator/utils/make_preload
@@ -90,7 +90,7 @@ foreach $file (@ARGV) {
 	open(FILE, $file) or error("failed to read $file: $!");
 	binmode(FILE);
 	$_ = <FILE>;
-	$_ = beam_strip($_);
+	$_ = beam_strip($_, $file);
 	close(FILE);
 	
 	push(@modules, "  {\"$module\", " . length($_) . ", preloaded_$module},\n");
@@ -147,20 +147,20 @@ sub error {
 }
 
 sub beam_strip {
-    my($beam) = @_;
+    my($beam,$file) = @_;
 
 
     my $size_left = length($beam);
     my %chunk;
     my %needed_chunk = ('Code' => 1,
-			'Atom' => 1,
+			'AtU8' => 1,
 			'ImpT' => 1,
 			'ExpT' => 1,
 			'StrT' => 1,
 			'FunT' => 1,
 			'LitT' => 1);
 
-    die "can't read Beam files for OTP R4 or earlier (sorry)"
+    die "$file: can't read Beam files for OTP R4 or earlier (sorry)"
 	if $beam =~ /^\x7fBEAM!/;
 
     #
@@ -177,7 +177,7 @@ sub beam_strip {
     die "form size $size greater than size ", $size_left, " of module"
 	if $size > $size_left;
     $size_left -= 4;
-    die "not a BEAM file: IFF form type is not 'BEAM'"
+    die "$file: not a BEAM file: IFF form type is not 'BEAM'"
 	unless $beam_id eq 'BEAM';
 
     #
@@ -196,6 +196,14 @@ sub beam_strip {
 	$size_left = length($beam);
     }
 
+    #
+    # Abort if there is no new-style 'AtU8' atom chunk.
+    #
+
+    exists $chunk{'AtU8'} or
+        die "$file: no 'AtU8' chunk (re-compile with " .
+        "OTP 20 or later)\n";
+
     #
     # Create a new beam file with only the useful chunk types.
     #
-- 
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