Allow target to specify about using minimum alignment vs preferred. Takes care of

FIXME: Override "preferred align" for double and long long for ARM apcs-gnu ABI.
Also part of rdar://9802874

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135940 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/TargetInfo.h b/include/clang/Basic/TargetInfo.h
index e09098ea05d95ce7903b38c4aee8c339581c2f3b..a8d12ce44603272cb12b7065bd8ea18c4d1d0b6b 100644 (file)
--- a/include/clang/Basic/TargetInfo.h
+++ b/include/clang/Basic/TargetInfo.h
@@ -88,6 +88,7 @@ protected:
 
   unsigned HasAlignMac68kSupport : 1;
   unsigned RealTypeUsesObjCFPRet : 3;
+  unsigned UsePreferredTypeAlign : 1;
 
   // TargetInfo Constructor.  Default initializes all fields.
   TargetInfo(const std::string &T);
@@ -272,6 +273,12 @@ public:
     return HasAlignMac68kSupport;
   }
 
+  /// usePreferredTypeAlign - Check whether this target uses minimum alignment
+  /// defined by ABI or some other preferred alignment.
+  bool usePreferredTypeAlign() const {
+    return UsePreferredTypeAlign;
+  }
+
   /// getTypeName - Return the user string for the specified integer type enum.
   /// For example, SignedShort -> "short".
   static const char *getTypeName(IntType T);

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 5463b7b7b05ff4f67c16ecc4e18fe74e9723c988..c6e2c20df7d63fdee3a387998d125ec25441c62d 100644 (file)
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -696,7 +696,10 @@ CharUnits ASTContext::getDeclAlign(const Decl *D, bool RefAsPointee) const {
         // Walk through any array types while we're at it.
         T = getBaseElementType(arrayType);
       }
-      Align = std::max(Align, getPreferredTypeAlign(T.getTypePtr()));
+      if (Target.usePreferredTypeAlign())
+        Align = std::max(Align, getPreferredTypeAlign(T.getTypePtr()));
+      else
+        Align = std::max(Align, getTypeAlign(T.getTypePtr()));
     }
 
     // Fields can be subject to extra alignment constraints, like if

diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index fdcff0a4dafac85a21c1399b23480dd8208b6d39..1435627562f5de4903abe6300cf14aec8ed99420 100644 (file)
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -1592,10 +1592,15 @@ CharUnits IntExprEvaluator::GetAlignOfType(QualType T) {
   //   result shall be the alignment of the referenced type."
   if (const ReferenceType *Ref = T->getAs<ReferenceType>())
     T = Ref->getPointeeType();
-
-  // __alignof is defined to return the preferred alignment.
-  return Info.Ctx.toCharUnitsFromBits(
-    Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
+ 
+  // __alignof defaults to returning the preferred alignment, but
+  // can be overridden by the specific target.
+  if (Info.Ctx.Target.usePreferredTypeAlign())
+    return Info.Ctx.toCharUnitsFromBits(
+      Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
+  else
+    return Info.Ctx.toCharUnitsFromBits(
+      Info.Ctx.getTypeAlign(T.getTypePtr()));
 }
 
 CharUnits IntExprEvaluator::GetAlignOfExpr(const Expr *E) {

diff --git a/lib/Basic/TargetInfo.cpp b/lib/Basic/TargetInfo.cpp
index 7ea51467c189aa816f81bb4eec2c1f1a7f1311db..c7a87b20eb8fbff209530d672e1419c37a13ba8d 100644 (file)
--- a/lib/Basic/TargetInfo.cpp
+++ b/lib/Basic/TargetInfo.cpp
@@ -65,6 +65,9 @@ TargetInfo::TargetInfo(const std::string &T) : Triple(T) {
   // Default to no types using fpret.
   RealTypeUsesObjCFPRet = 0;
 
+  // Default to using preferred type alignment.
+  UsePreferredTypeAlign = true;
+
   // Default to using the Itanium ABI.
   CXXABI = CXXABI_Itanium;
 

diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 3aebc41d71318a6eed7ba0f83f20d26c5ab0bf40..53f5c0abafcc6a7e7a87f8cffa46897d16d67bb2 100644 (file)
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -1978,11 +1978,13 @@ public:
                              "v64:32:64-v128:32:128-a0:0:32-n32");
       }
 
-      // FIXME: Override "preferred align" for double and long long.
+      // Default to using minimum alignment, not preferred.
+      UsePreferredTypeAlign = false;
     } else if (Name == "aapcs") {
       // FIXME: Enumerated types are variable width in straight AAPCS.
+
     } else if (Name == "aapcs-linux") {
-      ;
+
     } else
       return false;
 

diff --git a/test/Sema/align-arm-apcs-gnu.c b/test/Sema/align-arm-apcs-gnu.c
index a1a0f0e013cc93fe5dcfd44a22cc9694c0b201cc..575cf72bd41d5771ca5d03f72e0eb9e0097ff7d5 100644 (file)
--- a/test/Sema/align-arm-apcs-gnu.c
+++ b/test/Sema/align-arm-apcs-gnu.c
@@ -2,3 +2,15 @@
 
 struct s0 { double f0; int f1; };
 char chk0[__alignof__(struct s0) == 4 ? 1 : -1];
+
+double g1;
+short chk1[__alignof__(g1) == 4 ? 1 : -1]; 
+short chk2[__alignof__(double) == 4 ? 1 : -1];
+
+long long g2;
+short chk1[__alignof__(g2) == 4 ? 1 : -1]; 
+short chk2[__alignof__(long long) == 4 ? 1 : -1];
+
+_Complex double g3;
+short chk1[__alignof__(g3) == 4 ? 1 : -1]; 
+short chk2[__alignof__(_Complex double) == 4 ? 1 : -1];