[ThinLTO] Handle an external call from an import to an alias in dest

[oota-llvm.git] / lib / IR / DataLayout.cpp

diff --git a/lib/IR/DataLayout.cpp b/lib/IR/DataLayout.cpp
index c70d7c68a910a14be75057dac35a7a800864510d..5468f47bbfe62a3d8807d55265264858d0f05013 100644 (file)
--- a/lib/IR/DataLayout.cpp
+++ b/lib/IR/DataLayout.cpp
@@ -41,6 +41,7 @@ StructLayout::StructLayout(StructType *ST, const DataLayout &DL) {
   assert(!ST->isOpaque() && "Cannot get layout of opaque structs");
   StructAlignment = 0;
   StructSize = 0;
+  IsPadded = false;
   NumElements = ST->getNumElements();
 
   // Loop over each of the elements, placing them in memory.
@@ -49,8 +50,10 @@ StructLayout::StructLayout(StructType *ST, const DataLayout &DL) {
     unsigned TyAlign = ST->isPacked() ? 1 : DL.getABITypeAlignment(Ty);
 
     // Add padding if necessary to align the data element properly.
-    if ((StructSize & (TyAlign-1)) != 0)
+    if ((StructSize & (TyAlign-1)) != 0) {
+      IsPadded = true;
       StructSize = RoundUpToAlignment(StructSize, TyAlign);
+    }
 
     // Keep track of maximum alignment constraint.
     StructAlignment = std::max(TyAlign, StructAlignment);
@@ -64,8 +67,10 @@ StructLayout::StructLayout(StructType *ST, const DataLayout &DL) {
 
   // Add padding to the end of the struct so that it could be put in an array
   // and all array elements would be aligned correctly.
-  if ((StructSize & (StructAlignment-1)) != 0)
+  if ((StructSize & (StructAlignment-1)) != 0) {
+    IsPadded = true;
     StructSize = RoundUpToAlignment(StructSize, StructAlignment);
+  }
 }
 
 
@@ -150,8 +155,8 @@ DataLayout::InvalidPointerElem = { 0U, 0U, 0U, ~0U };
 const char *DataLayout::getManglingComponent(const Triple &T) {
   if (T.isOSBinFormatMachO())
     return "-m:o";
-  if (T.isOSWindows() && T.getArch() == Triple::x86 && T.isOSBinFormatCOFF())
-    return "-m:w";
+  if (T.isOSWindows() && T.isOSBinFormatCOFF())
+    return T.getArch() == Triple::x86 ? "-m:x" : "-m:w";
   return "-m:e";
 }
 
@@ -359,7 +364,10 @@ void DataLayout::parseSpecifier(StringRef Desc) {
         ManglingMode = MM_Mips;
         break;
       case 'w':
-        ManglingMode = MM_WINCOFF;
+        ManglingMode = MM_WinCOFF;
+        break;
+      case 'x':
+        ManglingMode = MM_WinCOFFX86;
         break;
       }
       break;
@@ -458,8 +466,8 @@ unsigned DataLayout::getAlignmentInfo(AlignTypeEnum AlignType,
       return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
 
     // The best match so far depends on what we're looking for.
-     if (AlignType == INTEGER_ALIGN &&
-         Alignments[i].AlignType == INTEGER_ALIGN) {
+    if (AlignType == INTEGER_ALIGN &&
+        Alignments[i].AlignType == INTEGER_ALIGN) {
       // The "best match" for integers is the smallest size that is larger than
       // the BitWidth requested.
       if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
@@ -479,9 +487,7 @@ unsigned DataLayout::getAlignmentInfo(AlignTypeEnum AlignType,
     // If we didn't find an integer alignment, fall back on most conservative.
     if (AlignType == INTEGER_ALIGN) {
       BestMatchIdx = LargestInt;
-    } else {
-      assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
-
+    } else if (AlignType == VECTOR_ALIGN) {
       // By default, use natural alignment for vector types. This is consistent
       // with what clang and llvm-gcc do.
       unsigned Align = getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
@@ -494,6 +500,19 @@ unsigned DataLayout::getAlignmentInfo(AlignTypeEnum AlignType,
     }
   }
 
+  // If we still couldn't find a reasonable default alignment, fall back
+  // to a simple heuristic that the alignment is the first power of two
+  // greater-or-equal to the store size of the type.  This is a reasonable
+  // approximation of reality, and if the user wanted something less
+  // less conservative, they should have specified it explicitly in the data
+  // layout.
+  if (BestMatchIdx == -1) {
+    unsigned Align = getTypeStoreSize(Ty);
+    if (Align & (Align-1))
+      Align = NextPowerOf2(Align);
+    return Align;
+  }
+
   // Since we got a "best match" index, just return it.
   return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
                  : Alignments[BestMatchIdx].PrefAlign;