6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-06-12 13:38:21 +00:00
Code Issues Projects Releases Wiki Activity

Revert r176408 and r176407 to address PR15540.

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179111 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nadav Rotem
2013-04-09 18:16:05 +00:00
parent b976e407dc
commit 8e4df489d0
4 changed files with 43 additions and 189 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
lib/Analysis/BasicAliasAnalysis.cpp
View File

@ -88,7 +88,7 @@ static uint64_t getObjectSize(const Value *V, const DataLayout &TD,
const TargetLibraryInfo &TLI,
bool RoundToAlign = false) {
uint64_t Size;
if (getUnderlyingObjectSize(V, Size, &TD, &TLI, RoundToAlign))
if (getObjectSize(V, Size, &TD, &TLI, RoundToAlign))
return Size;
return AliasAnalysis::UnknownSize;
}
@ -98,6 +98,35 @@ static uint64_t getObjectSize(const Value *V, const DataLayout &TD,
static bool isObjectSmallerThan(const Value *V, uint64_t Size,
const DataLayout &TD,
const TargetLibraryInfo &TLI) {
// Note that the meanings of the "object" are slightly different in the
// following contexts:
// c1: llvm::getObjectSize()
// c2: llvm.objectsize() intrinsic
// c3: isObjectSmallerThan()
// c1 and c2 share the same meaning; however, the meaning of "object" in c3
// refers to the "entire object".
//
// Consider this example:
// char *p = (char*)malloc(100)
// char *q = p+80;
//
// In the context of c1 and c2, the "object" pointed by q refers to the
// stretch of memory of q[0:19]. So, getObjectSize(q) should return 20.
//
// However, in the context of c3, the "object" refers to the chunk of memory
// being allocated. So, the "object" has 100 bytes, and q points to the middle
// the "object". In case q is passed to isObjectSmallerThan() as the 1st
// parameter, before the llvm::getObjectSize() is called to get the size of
// entire object, we should:
// - either rewind the pointer q to the base-address of the object in
// question (in this case rewind to p), or
// - just give up. It is up to caller to make sure the pointer is pointing
// to the base address the object.
//
// We go for 2nd option for simplicity.
if (!isIdentifiedObject(V))
return false;
// This function needs to use the aligned object size because we allow
// reads a bit past the end given sufficient alignment.
uint64_t ObjectSize = getObjectSize(V, TD, TLI, /*RoundToAlign*/true);