diff options
| -rw-r--r-- | llvm/lib/CodeGen/GlobalMerge.cpp | 11 | ||||
| -rw-r--r-- | llvm/lib/IR/DataLayout.cpp | 16 |
2 files changed, 16 insertions, 11 deletions
diff --git a/llvm/lib/CodeGen/GlobalMerge.cpp b/llvm/lib/CodeGen/GlobalMerge.cpp index f4526c64f1e..69d1e13cec7 100644 --- a/llvm/lib/CodeGen/GlobalMerge.cpp +++ b/llvm/lib/CodeGen/GlobalMerge.cpp @@ -462,17 +462,8 @@ bool GlobalMerge::doMerge(const SmallVectorImpl<GlobalVariable *> &Globals, for (j = i; j != -1; j = GlobalSet.find_next(j)) { Type *Ty = Globals[j]->getValueType(); - // Make sure we use the same alignment AsmPrinter would use. There - // currently isn't any helper to compute that, so we compute it - // explicitly here. - // - // getPreferredAlignment will sometimes return an alignment higher - // than the explicitly specified alignment; we must ignore that - // if the section is explicitly specified, to avoid inserting extra - // padding into that section. + // Make sure we use the same alignment AsmPrinter would use. unsigned Align = DL.getPreferredAlignment(Globals[j]); - if (Globals[j]->hasSection() && Globals[j]->getAlignment()) - Align = Globals[j]->getAlignment(); unsigned Padding = alignTo(MergedSize, Align) - MergedSize; MergedSize += Padding; MergedSize += DL.getTypeAllocSize(Ty); diff --git a/llvm/lib/IR/DataLayout.cpp b/llvm/lib/IR/DataLayout.cpp index 62c67127276..18d502a52ca 100644 --- a/llvm/lib/IR/DataLayout.cpp +++ b/llvm/lib/IR/DataLayout.cpp @@ -808,15 +808,29 @@ int64_t DataLayout::getIndexedOffsetInType(Type *ElemTy, /// global. This includes an explicitly requested alignment (if the global /// has one). unsigned DataLayout::getPreferredAlignment(const GlobalVariable *GV) const { + unsigned GVAlignment = GV->getAlignment(); + // If a section is specified, always precisely honor explicit alignment, + // so we don't insert padding into a section we don't control. + if (GVAlignment && GV->hasSection()) + return GVAlignment; + + // If no explicit alignment is specified, compute the alignment based on + // the IR type. If an alignment is specified, increase it to match the ABI + // alignment of the IR type. + // + // FIXME: Not sure it makes sense to use the alignment of the type if + // there's already an explicit alignment specification. Type *ElemType = GV->getValueType(); unsigned Alignment = getPrefTypeAlignment(ElemType); - unsigned GVAlignment = GV->getAlignment(); if (GVAlignment >= Alignment) { Alignment = GVAlignment; } else if (GVAlignment != 0) { Alignment = std::max(GVAlignment, getABITypeAlignment(ElemType)); } + // If no explicit alignment is specified, and the global is large, increase + // the alignment to 16. + // FIXME: Why 16, specifically? if (GV->hasInitializer() && GVAlignment == 0) { if (Alignment < 16) { // If the global is not external, see if it is large. If so, give it a |
