Add field PaddingType to ABIArgInfo which specifies the type of padding that

is inserted before the real argument. Padding is needed to ensure the backend
reads from or writes to the correct argument slots when the original alignment
of a byval structure is unavailable due to flattening.

llvm-svn: 147699

1 files changed, 15 insertions, 6 deletions

diff --git a/clang/lib/CodeGen/ABIInfo.h b/clang/lib/CodeGen/ABIInfo.h
index 138123816c3..2853bc80a5d 100644
--- a/clang/lib/CodeGen/ABIInfo.h
+++ b/clang/lib/CodeGen/ABIInfo.h
@@ -42,7 +42,8 @@ namespace clang {
       /// type, or by coercing to another specified type stored in
       /// 'CoerceToType').  If an offset is specified (in UIntData), then the
       /// argument passed is offset by some number of bytes in the memory
-      /// representation.
+      /// representation. A dummy argument is emitted before the real argument
+      /// if the specified type stored in "PaddingType" is not zero.
       Direct,
 
       /// Extend - Valid only for integer argument types. Same as 'direct'
@@ -69,19 +70,22 @@ namespace clang {
   private:
     Kind TheKind;
     llvm::Type *TypeData;
+    llvm::Type *PaddingType; // Currently allowed only for Direct.
     unsigned UIntData;
     bool BoolData0;
     bool BoolData1;
 
-    ABIArgInfo(Kind K, llvm::Type *TD=0,
-               unsigned UI=0, bool B0 = false, bool B1 = false)
-      : TheKind(K), TypeData(TD), UIntData(UI), BoolData0(B0), BoolData1(B1) {}
+    ABIArgInfo(Kind K, llvm::Type *TD=0, unsigned UI=0,
+               bool B0 = false, bool B1 = false, llvm::Type* P = 0)
+      : TheKind(K), TypeData(TD), PaddingType(P), UIntData(UI), BoolData0(B0),
+        BoolData1(B1) {}
 
   public:
     ABIArgInfo() : TheKind(Direct), TypeData(0), UIntData(0) {}
 
-    static ABIArgInfo getDirect(llvm::Type *T = 0, unsigned Offset = 0) {
-      return ABIArgInfo(Direct, T, Offset);
+    static ABIArgInfo getDirect(llvm::Type *T = 0, unsigned Offset = 0,
+                                llvm::Type *Padding = 0) {
+      return ABIArgInfo(Direct, T, Offset, false, false, Padding);
     }
     static ABIArgInfo getExtend(llvm::Type *T = 0) {
       return ABIArgInfo(Extend, T, 0);
@@ -113,6 +117,11 @@ namespace clang {
       assert((isDirect() || isExtend()) && "Not a direct or extend kind");
       return UIntData;
     }
+
+    llvm::Type *getPaddingType() const {
+      return PaddingType;
+    }
+
     llvm::Type *getCoerceToType() const {
       assert(canHaveCoerceToType() && "Invalid kind!");
       return TypeData;