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* [gcc r13-4369] libstdc++: Fix _Hash_bytes for I16LP32 targets [PR107885]
@ 2022-11-28 16:57 Jonathan Wakely
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From: Jonathan Wakely @ 2022-11-28 16:57 UTC (permalink / raw)
To: gcc-cvs, libstdc++-cvs
https://gcc.gnu.org/g:7b79fa930917da735f02b4f6911dfbb0a91f9714
commit r13-4369-g7b79fa930917da735f02b4f6911dfbb0a91f9714
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Mon Nov 28 10:52:23 2022 +0000
libstdc++: Fix _Hash_bytes for I16LP32 targets [PR107885]
For H8/300 size_t is 32 bits wide, but (unsigned char)buf[2] << 16
promotes to int which is only 16 bits wide. The shift is then undefined.
This fixes it by converting to size_t before shifting.
libstdc++-v3/ChangeLog:
PR libstdc++/107885
* libsupc++/hash_bytes.cc (_Hash_bytes): Convert to size_t
instead of implicit integer promotion to 16 bits.
Diff:
---
libstdc++-v3/libsupc++/hash_bytes.cc | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/libstdc++-v3/libsupc++/hash_bytes.cc b/libstdc++-v3/libsupc++/hash_bytes.cc
index ffdd04f7602..67e2dbb1a0f 100644
--- a/libstdc++-v3/libsupc++/hash_bytes.cc
+++ b/libstdc++-v3/libsupc++/hash_bytes.cc
@@ -90,17 +90,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
len -= 4;
}
+ size_t k;
// Handle the last few bytes of the input array.
switch(len)
{
case 3:
- hash ^= static_cast<unsigned char>(buf[2]) << 16;
+ k = static_cast<unsigned char>(buf[2]);
+ hash ^= k << 16;
[[gnu::fallthrough]];
case 2:
- hash ^= static_cast<unsigned char>(buf[1]) << 8;
+ k = static_cast<unsigned char>(buf[1]);
+ hash ^= k << 8;
[[gnu::fallthrough]];
case 1:
- hash ^= static_cast<unsigned char>(buf[0]);
+ k = static_cast<unsigned char>(buf[0]);
+ hash ^= k;
hash *= m;
};
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