1 files changed, 6 insertions, 84 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 6f27d879a99..aea99dbbafd 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -19,6 +19,7 @@
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
 #include "ConstantEmitter.h"
+#include "PatternInit.h"
 #include "TargetInfo.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/CharUnits.h"
@@ -984,92 +985,13 @@ static bool shouldSplitConstantStore(CodeGenModule &CGM,
   return false;
 }
 
-static llvm::Constant *patternFor(CodeGenModule &CGM, llvm::Type *Ty) {
-  // The following value is a guaranteed unmappable pointer value and has a
-  // repeated byte-pattern which makes it easier to synthesize. We use it for
-  // pointers as well as integers so that aggregates are likely to be
-  // initialized with this repeated value.
-  constexpr uint64_t LargeValue = 0xAAAAAAAAAAAAAAAAull;
-  // For 32-bit platforms it's a bit trickier because, across systems, only the
-  // zero page can reasonably be expected to be unmapped, and even then we need
-  // a very low address. We use a smaller value, and that value sadly doesn't
-  // have a repeated byte-pattern. We don't use it for integers.
-  constexpr uint32_t SmallValue = 0x000000AA;
-  // Floating-point values are initialized as NaNs because they propagate. Using
-  // a repeated byte pattern means that it will be easier to initialize
-  // all-floating-point aggregates and arrays with memset. Further, aggregates
-  // which mix integral and a few floats might also initialize with memset
-  // followed by a handful of stores for the floats. Using fairly unique NaNs
-  // also means they'll be easier to distinguish in a crash.
-  constexpr bool NegativeNaN = true;
-  constexpr uint64_t NaNPayload = 0xFFFFFFFFFFFFFFFFull;
-  if (Ty->isIntOrIntVectorTy()) {
-    unsigned BitWidth = cast<llvm::IntegerType>(
-                            Ty->isVectorTy() ? Ty->getVectorElementType() : Ty)
-                            ->getBitWidth();
-    if (BitWidth <= 64)
-      return llvm::ConstantInt::get(Ty, LargeValue);
-    return llvm::ConstantInt::get(
-        Ty, llvm::APInt::getSplat(BitWidth, llvm::APInt(64, LargeValue)));
-  }
-  if (Ty->isPtrOrPtrVectorTy()) {
-    auto *PtrTy = cast<llvm::PointerType>(
-        Ty->isVectorTy() ? Ty->getVectorElementType() : Ty);
-    unsigned PtrWidth = CGM.getContext().getTargetInfo().getPointerWidth(
-        PtrTy->getAddressSpace());
-    llvm::Type *IntTy = llvm::IntegerType::get(CGM.getLLVMContext(), PtrWidth);
-    uint64_t IntValue;
-    switch (PtrWidth) {
-    default:
-      llvm_unreachable("pattern initialization of unsupported pointer width");
-    case 64:
-      IntValue = LargeValue;
-      break;
-    case 32:
-      IntValue = SmallValue;
-      break;
-    }
-    auto *Int = llvm::ConstantInt::get(IntTy, IntValue);
-    return llvm::ConstantExpr::getIntToPtr(Int, PtrTy);
-  }
-  if (Ty->isFPOrFPVectorTy()) {
-    unsigned BitWidth = llvm::APFloat::semanticsSizeInBits(
-        (Ty->isVectorTy() ? Ty->getVectorElementType() : Ty)
-            ->getFltSemantics());
-    llvm::APInt Payload(64, NaNPayload);
-    if (BitWidth >= 64)
-      Payload = llvm::APInt::getSplat(BitWidth, Payload);
-    return llvm::ConstantFP::getQNaN(Ty, NegativeNaN, &Payload);
-  }
-  if (Ty->isArrayTy()) {
-    // Note: this doesn't touch tail padding (at the end of an object, before
-    // the next array object). It is instead handled by replaceUndef.
-    auto *ArrTy = cast<llvm::ArrayType>(Ty);
-    llvm::SmallVector<llvm::Constant *, 8> Element(
-        ArrTy->getNumElements(), patternFor(CGM, ArrTy->getElementType()));
-    return llvm::ConstantArray::get(ArrTy, Element);
-  }
-
-  // Note: this doesn't touch struct padding. It will initialize as much union
-  // padding as is required for the largest type in the union. Padding is
-  // instead handled by replaceUndef. Stores to structs with volatile members
-  // don't have a volatile qualifier when initialized according to C++. This is
-  // fine because stack-based volatiles don't really have volatile semantics
-  // anyways, and the initialization shouldn't be observable.
-  auto *StructTy = cast<llvm::StructType>(Ty);
-  llvm::SmallVector<llvm::Constant *, 8> Struct(StructTy->getNumElements());
-  for (unsigned El = 0; El != Struct.size(); ++El)
-    Struct[El] = patternFor(CGM, StructTy->getElementType(El));
-  return llvm::ConstantStruct::get(StructTy, Struct);
-}
-
 enum class IsPattern { No, Yes };
 
 /// Generate a constant filled with either a pattern or zeroes.
 static llvm::Constant *patternOrZeroFor(CodeGenModule &CGM, IsPattern isPattern,
                                         llvm::Type *Ty) {
   if (isPattern == IsPattern::Yes)
-    return patternFor(CGM, Ty);
+    return initializationPatternFor(CGM, Ty);
   else
     return llvm::Constant::getNullValue(Ty);
 }
@@ -1294,8 +1216,8 @@ static void emitStoresForPatternInit(CodeGenModule &CGM, const VarDecl &D,
                                      Address Loc, bool isVolatile,
                                      CGBuilderTy &Builder) {
   llvm::Type *ElTy = Loc.getElementType();
-  llvm::Constant *constant =
-      constWithPadding(CGM, IsPattern::Yes, patternFor(CGM, ElTy));
+  llvm::Constant *constant = constWithPadding(
+      CGM, IsPattern::Yes, initializationPatternFor(CGM, ElTy));
   assert(!isa<llvm::UndefValue>(constant));
   emitStoresForConstant(CGM, D, Loc, isVolatile, Builder, constant);
 }
@@ -1818,8 +1740,8 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
 
     case LangOptions::TrivialAutoVarInitKind::Pattern: {
       llvm::Type *ElTy = Loc.getElementType();
-      llvm::Constant *Constant =
-          constWithPadding(CGM, IsPattern::Yes, patternFor(CGM, ElTy));
+      llvm::Constant *Constant = constWithPadding(
+          CGM, IsPattern::Yes, initializationPatternFor(CGM, ElTy));
       CharUnits ConstantAlign = getContext().getTypeAlignInChars(VlaSize.Type);
       llvm::BasicBlock *SetupBB = createBasicBlock("vla-setup.loop");
       llvm::BasicBlock *LoopBB = createBasicBlock("vla-init.loop");