From: Chris Lattner <sabre@nondot.org>
Date: Wed, 18 Jul 2007 18:26:58 +0000 (+0000)
Subject: implement sizeof/alignof support for structs, unions and complex.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5d2a6303467184b1f159bb6556efc434e50e3c28;p=clang

implement sizeof/alignof support for structs, unions and complex.

This allows us to compile this:

struct abc { char A; double D; };

int foo() {
  return sizeof(struct abc);
  return __alignof__(struct abc);
}

Into:

        ret i32 16
        ret i32 8



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40010 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/AST/ASTContext.cpp b/AST/ASTContext.cpp
index 41905c8ecd..f45051bf36 100644
--- a/AST/ASTContext.cpp
+++ b/AST/ASTContext.cpp
@@ -157,16 +157,15 @@ ASTContext::getTypeInfo(QualType T, SourceLocation L) {
   uint64_t Size;
   unsigned Align;
   switch (T->getTypeClass()) {
+  case Type::FunctionNoProto:
+  case Type::FunctionProto:
+    assert(0 && "Incomplete types have no size!");
   default:
-  case Type::Complex:
   case Type::Array:
   case Type::Vector:
   case Type::TypeName:
-  case Type::Tagged:
     assert(0 && "Unimplemented type sizes!");
-  case Type::FunctionNoProto:
-  case Type::FunctionProto:
-    assert(0 && "Incomplete types have no size!");
+
   case Type::Builtin: {
     // FIXME: need to use TargetInfo to derive the target specific sizes. This
     // implementation will suffice for play with vector support.
@@ -196,8 +195,28 @@ ASTContext::getTypeInfo(QualType T, SourceLocation L) {
   case Type::Pointer: Target.getPointerInfo(Size, Align, L); break;
   case Type::Reference:
     // "When applied to a reference or a reference type, the result is the size
-    // of the referenced type." C++98 5.3.3p2: expr.sizeof
+    // of the referenced type." C++98 5.3.3p2: expr.sizeof.
+    // FIXME: This is wrong for struct layout!
     return getTypeInfo(cast<ReferenceType>(T)->getReferenceeType(), L);
+    
+  case Type::Complex: {
+    // Complex types have the same alignment as their elements, but twice the
+    // size.
+    std::pair<uint64_t, unsigned> EltInfo = 
+      getTypeInfo(cast<ComplexType>(T)->getElementType(), L);
+    Size = EltInfo.first*2;
+    Align = EltInfo.second;
+    break;
+  }
+  case Type::Tagged:
+    if (RecordType *RT = dyn_cast<RecordType>(cast<TagType>(T))) {
+      const RecordLayout &Layout = getRecordLayout(RT->getDecl(), L);
+      Size = Layout.getSize();
+      Align = Layout.getAlignment();
+      break;
+    }
+    // FIXME: Handle enums.
+    assert(0 && "Unimplemented type sizes!");
   }
   
   assert(Align && (Align & (Align-1)) == 0 && "Alignment must be power of 2");
@@ -267,6 +286,9 @@ const RecordLayout &ASTContext::getRecordLayout(const RecordDecl *D,
       RecordAlign = std::max(RecordAlign, FieldAlign);
     }
   }
+  
+  NewEntry->SetLayout(RecordSize, RecordAlign, FieldOffsets);
+  return *NewEntry;
 }
 
 
diff --git a/include/clang/AST/RecordLayout.h b/include/clang/AST/RecordLayout.h
index 5169737636..dec6e3ae91 100644
--- a/include/clang/AST/RecordLayout.h
+++ b/include/clang/AST/RecordLayout.h
@@ -35,7 +35,7 @@ class RecordLayout {
   }
   
   void SetLayout(uint64_t size, unsigned alignment, uint64_t *fieldOffsets) {
-    Size = Size; Alignment = alignment;
+    Size = size; Alignment = alignment;
     FieldOffsets = fieldOffsets;
   }
   
diff --git a/include/clang/AST/Type.h b/include/clang/AST/Type.h
index 7ec97cff49..1c2d9b6f60 100644
--- a/include/clang/AST/Type.h
+++ b/include/clang/AST/Type.h
@@ -646,9 +646,13 @@ class RecordType : public TagType {
   RecordType(); // DO NOT IMPLEMENT
 public:
     
-  RecordDecl *getDecl() const {
+  const RecordDecl *getDecl() const {
     return reinterpret_cast<RecordDecl*>(TagType::getDecl());
   }
+  RecordDecl *getDecl() {
+    return reinterpret_cast<RecordDecl*>(TagType::getDecl());
+  }
+  
   // FIXME: This predicate is a helper to QualType/Type. It needs to 
   // recursively check all fields for const-ness. If any field is declared
   // const, it needs to return false.