diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/IPO/LowerTypeTests.cpp | 45 |
1 files changed, 26 insertions, 19 deletions
diff --git a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp index f7371284f47..716d4e8ede7 100644 --- a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp +++ b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp @@ -759,43 +759,50 @@ void LowerTypeTestsModule::buildBitSetsFromGlobalVariables( // Build a new global with the combined contents of the referenced globals. // This global is a struct whose even-indexed elements contain the original // contents of the referenced globals and whose odd-indexed elements contain - // any padding required to align the next element to the next power of 2. + // any padding required to align the next element to the next power of 2 plus + // any additional padding required to meet its alignment requirements. std::vector<Constant *> GlobalInits; const DataLayout &DL = M.getDataLayout(); + DenseMap<GlobalTypeMember *, uint64_t> GlobalLayout; + uint64_t MaxAlign = 0; + uint64_t CurOffset = 0; + uint64_t DesiredPadding = 0; for (GlobalTypeMember *G : Globals) { - GlobalVariable *GV = cast<GlobalVariable>(G->getGlobal()); + auto *GV = cast<GlobalVariable>(G->getGlobal()); + uint64_t Align = GV->getAlignment(); + if (Align == 0) + Align = DL.getABITypeAlignment(GV->getValueType()); + MaxAlign = std::max(MaxAlign, Align); + uint64_t GVOffset = alignTo(CurOffset + DesiredPadding, Align); + GlobalLayout[G] = GVOffset; + if (GVOffset != 0) { + uint64_t Padding = GVOffset - CurOffset; + GlobalInits.push_back( + ConstantAggregateZero::get(ArrayType::get(Int8Ty, Padding))); + } + GlobalInits.push_back(GV->getInitializer()); uint64_t InitSize = DL.getTypeAllocSize(GV->getValueType()); + CurOffset = GVOffset + InitSize; - // Compute the amount of padding required. - uint64_t Padding = NextPowerOf2(InitSize - 1) - InitSize; + // Compute the amount of padding that we'd like for the next element. + DesiredPadding = NextPowerOf2(InitSize - 1) - InitSize; // Experiments of different caps with Chromium on both x64 and ARM64 // have shown that the 32-byte cap generates the smallest binary on // both platforms while different caps yield similar performance. // (see https://lists.llvm.org/pipermail/llvm-dev/2018-July/124694.html) - if (Padding > 32) - Padding = alignTo(InitSize, 32) - InitSize; - - GlobalInits.push_back( - ConstantAggregateZero::get(ArrayType::get(Int8Ty, Padding))); + if (DesiredPadding > 32) + DesiredPadding = alignTo(InitSize, 32) - InitSize; } - if (!GlobalInits.empty()) - GlobalInits.pop_back(); + Constant *NewInit = ConstantStruct::getAnon(M.getContext(), GlobalInits); auto *CombinedGlobal = new GlobalVariable(M, NewInit->getType(), /*isConstant=*/true, GlobalValue::PrivateLinkage, NewInit); + CombinedGlobal->setAlignment(MaxAlign); StructType *NewTy = cast<StructType>(NewInit->getType()); - const StructLayout *CombinedGlobalLayout = DL.getStructLayout(NewTy); - - // Compute the offsets of the original globals within the new global. - DenseMap<GlobalTypeMember *, uint64_t> GlobalLayout; - for (unsigned I = 0; I != Globals.size(); ++I) - // Multiply by 2 to account for padding elements. - GlobalLayout[Globals[I]] = CombinedGlobalLayout->getElementOffset(I * 2); - lowerTypeTestCalls(TypeIds, CombinedGlobal, GlobalLayout); // Build aliases pointing to offsets into the combined global for each |
