Changeset 242215 in webkit

Timestamp:

Feb 28, 2019 12:48:50 PM (5 years ago)

Author:

mark.lam@apple.com

Message:

cloop.rb shift mask should depend on the word size being shifted.
​https://bugs.webkit.org/show_bug.cgi?id=195181
<rdar://problem/48484164>

Reviewed by Yusuke Suzuki.

Previously, we're always masking the shift amount with 0x1f. This is only correct
for 32-bit words. For 64-bit words, the mask should be 0x3f. For pointer sized
shifts, the mask depends on sizeof(uintptr_t).

• offlineasm/cloop.rb:

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• offlineasm/cloop.rb (modified) (2 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2019-02-28  Mark Lam  <mark.lam@apple.com>
+
+        cloop.rb shift mask should depend on the word size being shifted.
+        https://bugs.webkit.org/show_bug.cgi?id=195181
+        <rdar://problem/48484164>
+
+        Reviewed by Yusuke Suzuki.
+
+        Previously, we're always masking the shift amount with 0x1f.  This is only correct
+        for 32-bit words.  For 64-bit words, the mask should be 0x3f.  For pointer sized
+        shifts, the mask depends on sizeof(uintptr_t).
+
+        * offlineasm/cloop.rb:
+
 2019-02-28  Justin Fan  <justin_fan@apple.com>
 

trunk/Source/JavaScriptCore/offlineasm/cloop.rb

@@ -1 @@
-# Copyright (C) 2012-2018 Apple Inc. All rights reserved.
+# Copyright (C) 2012-2019 Apple Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -427 +427 @@
         truncationFooter = ""
     end
-    $asm.putc "#{dst.clLValue(type)} = #{truncationHeader}#{operands[1].clValue(type)} #{operator} (#{operands[0].clValue(:int)} & 0x1f)#{truncationFooter};"
+    # FIXME: rename :int to :intptr to be match their expected names from C++. Ditto for :uint.
+    # https://bugs.webkit.org/show_bug.cgi?id=195183
+    shiftMask = "((sizeof(uintptr_t) == 8) ? 0x3f : 0x1f)" if type == :int || type == :uint
+    shiftMask = "0x3f" if type == :int64 || type == :uint64
+    shiftMask = "0x1f" if type == :int32 || type == :uint32
+    $asm.putc "#{dst.clLValue(type)} = #{truncationHeader}#{operands[1].clValue(type)} #{operator} (#{operands[0].clValue(:int)} & #{shiftMask})#{truncationFooter};"
 end