Bug fix in BumpPtrAllocator: don't assume that all objects have the same alignment. "Bump" of the pointer for the next allocated object to be of the specified alignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50362 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
index 5961afe..8ccd390 100644
--- a/lib/Support/Allocator.cpp
+++ b/lib/Support/Allocator.cpp
@@ -46,13 +46,16 @@
/// Allocate - Allocate and return at least the specified number of bytes.
///
void *Allocate(unsigned AllocSize, unsigned Alignment, MemRegion **RegPtr) {
- // Round size up to an even multiple of the alignment.
- AllocSize = (AllocSize+Alignment-1) & ~(Alignment-1);
- // If there is space in this region, return it.
- if (unsigned(NextPtr+AllocSize-(char*)this) <= RegionSize) {
- void *Result = NextPtr;
- NextPtr += AllocSize;
+ char* Result = (char*) (((uintptr_t) (NextPtr+Alignment-1))
+ & ~(Alignment-1));
+
+ // Speculate the new value of NextPtr.
+ char* NextPtrTmp = Result + AllocSize;
+
+ // If we are still within the current region, return Result.
+ if (unsigned (NextPtrTmp - (char*) this) <= RegionSize) {
+ NextPtr = NextPtrTmp;
return Result;
}