6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-14 11:32:34 +00:00
Code Issues Projects Releases Wiki Activity

Aligned and unaligned copies of the same string

Browse Source 
were not hashing to the same value.  Analysis
and patch by Frits van Bommel!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119770 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen 2010-11-19 00:48:58 +00:00
parent cb21d1c9fd
commit c81c7fe643
1 changed files with 22 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
lib/Support/FoldingSet.cpp
View File

@ -18,6 +18,7 @@
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/System/Host.h"
#include <cassert>
#include <cstring>
using namespace llvm;
@ -110,18 +111,32 @@ void FoldingSetNodeID::AddString(StringRef String) {
Pos = (Units + 1) * 4;
} else {
// Otherwise do it the hard way.
for (Pos += 4; Pos <= Size; Pos += 4) {
unsigned V = ((unsigned char)String[Pos - 4] << 24) |
((unsigned char)String[Pos - 3] << 16) |
((unsigned char)String[Pos - 2] << 8) |
(unsigned char)String[Pos - 1];
Bits.push_back(V);
// To be compatible with above bulk transfer, we need to take endianness
// into account.
if (sys::isBigEndianHost()) {
for (Pos += 4; Pos <= Size; Pos += 4) {
unsigned V = ((unsigned char)String[Pos - 4] << 24) |
((unsigned char)String[Pos - 3] << 16) |
((unsigned char)String[Pos - 2] << 8) |
(unsigned char)String[Pos - 1];
Bits.push_back(V);
}
} else {
assert(sys::isLittleEndianHost() && "Unexpected host endianness");
for (Pos += 4; Pos <= Size; Pos += 4) {
unsigned V = ((unsigned char)String[Pos - 1] << 24) |
((unsigned char)String[Pos - 2] << 16) |
((unsigned char)String[Pos - 3] << 8) |
(unsigned char)String[Pos - 4];
Bits.push_back(V);
}
}
}
// With the leftover bits.
unsigned V = 0;
// Pos will have overshot size by 4 - #bytes left over.
// Pos will have overshot size by 4 - #bytes left over.
// No need to take endianness into account here - this is always executed.
switch (Pos - Size) {
case 1: V = (V << 8) | (unsigned char)String[Size - 3]; // Fall thru.
case 2: V = (V << 8) | (unsigned char)String[Size - 2]; // Fall thru.