Instcombine: destructor loads of structs that do not contains padding

[oota-llvm.git] / include / llvm / IR / DataLayout.h

diff --git a/include/llvm/IR/DataLayout.h b/include/llvm/IR/DataLayout.h
index deda87795690bdd98fd2e3269b5753b5b8f4d024..19a3a6661feb668955c7d7ad80a3452c08b6ef9e 100644 (file)
--- a/include/llvm/IR/DataLayout.h
+++ b/include/llvm/IR/DataLayout.h
@@ -108,7 +108,14 @@ private:
 
   unsigned StackNaturalAlign;
 
-  enum ManglingModeT { MM_None, MM_ELF, MM_MachO, MM_WINCOFF, MM_Mips };
+  enum ManglingModeT {
+    MM_None,
+    MM_ELF,
+    MM_MachO,
+    MM_WinCOFF,
+    MM_WinCOFFX86,
+    MM_Mips
+  };
   ManglingModeT ManglingMode;
 
   SmallVector<unsigned char, 8> LegalIntWidths;
@@ -215,7 +222,9 @@ public:
   /// This representation is in the same format accepted by the string
   /// constructor above. This should not be used to compare two DataLayout as
   /// different string can represent the same layout.
-  std::string getStringRepresentation() const { return StringRepresentation; }
+  const std::string &getStringRepresentation() const {
+    return StringRepresentation;
+  }
 
   /// \brief Test if the DataLayout was constructed from an empty string.
   bool isDefault() const { return StringRepresentation.empty(); }
@@ -244,7 +253,7 @@ public:
   unsigned getStackAlignment() const { return StackNaturalAlign; }
 
   bool hasMicrosoftFastStdCallMangling() const {
-    return ManglingMode == MM_WINCOFF;
+    return ManglingMode == MM_WinCOFFX86;
   }
 
   bool hasLinkerPrivateGlobalPrefix() const { return ManglingMode == MM_MachO; }
@@ -252,7 +261,7 @@ public:
   const char *getLinkerPrivateGlobalPrefix() const {
     if (ManglingMode == MM_MachO)
       return "l";
-    return getPrivateGlobalPrefix();
+    return "";
   }
 
   char getGlobalPrefix() const {
@@ -260,9 +269,10 @@ public:
     case MM_None:
     case MM_ELF:
     case MM_Mips:
+    case MM_WinCOFF:
       return '\0';
     case MM_MachO:
-    case MM_WINCOFF:
+    case MM_WinCOFFX86:
       return '_';
     }
     llvm_unreachable("invalid mangling mode");
@@ -277,7 +287,8 @@ public:
     case MM_Mips:
       return "$";
     case MM_MachO:
-    case MM_WINCOFF:
+    case MM_WinCOFF:
+    case MM_WinCOFFX86:
       return "L";
     }
     llvm_unreachable("invalid mangling mode");
@@ -464,7 +475,8 @@ inline LLVMTargetDataRef wrap(const DataLayout *P) {
 class StructLayout {
   uint64_t StructSize;
   unsigned StructAlignment;
-  unsigned NumElements;
+  bool IsPadded : 1;
+  unsigned NumElements : 31;
   uint64_t MemberOffsets[1]; // variable sized array!
 public:
   uint64_t getSizeInBytes() const { return StructSize; }
@@ -473,6 +485,10 @@ public:
 
   unsigned getAlignment() const { return StructAlignment; }
 
+  /// Returns whether the struct has padding or not between its fields.
+  /// NB: Padding in nested element is not taken into account.
+  bool hasPadding() const { return IsPadded; }
+
   /// \brief Given a valid byte offset into the structure, returns the structure
   /// index that contains it.
   unsigned getElementContainingOffset(uint64_t Offset) const;