<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Sep 6, 2014 at 7:05 PM, Lang Hames <span dir="ltr"><<a href="mailto:lhames@gmail.com" target="_blank">lhames@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: lhames<br>
Date: Sat Sep  6 21:05:26 2014<br>
New Revision: 217325<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=217325&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=217325&view=rev</a><br>
Log:<br>
[MCJIT] Fix a bug RuntimeDyldImpl's read/writeBytesUnaligned methods.<br>
<br>
The previous implementation was writing to the high-bytes of integers on BE<br>
targets (when run on LE hosts).<br></blockquote><div><br></div><div>Not testable? (curious what limitations of your new test infrastructure (or curiosities of this issue) make it not applicable to testing this bug)<br><br>& any nice way to factor the (admittedly minor) duplication in each of these codepaths? (could have a function that takes the increment (1 or -1), non-type template parameter if necessary, but it looks simple/inlinable?)</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<a href="http://llvm.org/PR20640" target="_blank">http://llvm.org/PR20640</a><br>
<br>
<br>
Modified:<br>
    llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp<br>
<br>
Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp?rev=217325&r1=217324&r2=217325&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp?rev=217325&r1=217324&r2=217325&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp (original)<br>
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp Sat Sep  6 21:05:26 2014<br>
@@ -398,32 +398,30 @@ unsigned RuntimeDyldImpl::computeSection<br>
 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,<br>
                                              unsigned Size) const {<br>
   uint64_t Result = 0;<br>
-  uint8_t *Dst = reinterpret_cast<uint8_t*>(&Result);<br>
-<br>
-  if (IsTargetLittleEndian == sys::IsLittleEndianHost) {<br>
-    if (!sys::IsLittleEndianHost)<br>
-      Dst += sizeof(Result) - Size;<br>
-    memcpy(Dst, Src, Size);<br>
-  } else {<br>
-    Dst += Size - 1;<br>
-    for (unsigned i = 0; i < Size; ++i)<br>
-      *Dst-- = *Src++;<br>
-  }<br>
+  if (IsTargetLittleEndian) {<br>
+    Src += Size - 1;<br>
+    while (Size--)<br>
+      Result = (Result << 8) | *Src--;</blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
+  } else<br>
+    while (Size--)<br>
+      Result = (Result << 8) | *Src++; </blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
   return Result;<br>
 }<br>
<br>
 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,<br>
                                           unsigned Size) const {<br>
-  uint8_t *Src = reinterpret_cast<uint8_t*>(&Value);<br>
-  if (IsTargetLittleEndian == sys::IsLittleEndianHost) {<br>
-    if (!sys::IsLittleEndianHost)<br>
-      Src += sizeof(Value) - Size;<br>
-    memcpy(Dst, Src, Size);<br>
+  if (IsTargetLittleEndian) {<br>
+    while (Size--) {<br>
+      *Dst++ = Value & 0xFF;<br>
+      Value >>= 8;<br>
+    }<br>
   } else {<br>
-    Src += Size - 1;<br>
-    for (unsigned i = 0; i < Size; ++i)<br>
-      *Dst++ = *Src--;<br>
+    Dst += Size - 1;<br>
+    while (Size--) {<br>
+      *Dst-- = Value & 0xFF;<br>
+      Value >>= 8;<br>
+    }<br>
   }<br>
 }<br>
<br>
<br>
<br>
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</blockquote></div><br></div></div>