A few more tweaks to the blocks AST representation:

  - BlockDeclRefExprs always store VarDecls
  - BDREs no longer store copy expressions
  - BlockDecls now store a list of captured variables, information about
    how they're captured, and a copy expression if necessary
    
With that in hand, change IR generation to use the captures data in       
blocks instead of walking the block independently.        

Additionally, optimize block layout by emitting fields in descending
alignment order, with a heuristic for filling in words when alignment
of the end of the block header is insufficient for the most aligned
field.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125005 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 53 insertions, 39 deletions

diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 24c080e517..9627125491 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -1000,8 +1000,8 @@ public:
   /// forward references will be filled in with empty bodies if no
   /// definition is seen. The return value has type ProtocolPtrTy.
   virtual llvm::Constant *GetOrEmitProtocolRef(const ObjCProtocolDecl *PD)=0;
-  virtual llvm::Constant *GCBlockLayout(CodeGen::CodeGenFunction &CGF,
-                      const llvm::SmallVectorImpl<const Expr *> &);
+  virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
+                                             const CGBlockInfo &blockInfo);
   
 };
 
@@ -1667,12 +1667,14 @@ static Qualifiers::GC GetGCAttrTypeForType(ASTContext &Ctx, QualType FQT) {
   return Qualifiers::GCNone;
 }
 
-llvm::Constant *CGObjCCommonMac::GCBlockLayout(CodeGen::CodeGenFunction &CGF,
-              const llvm::SmallVectorImpl<const Expr *> &BlockLayout) {
-  llvm::Constant *NullPtr = 
+llvm::Constant *CGObjCCommonMac::BuildGCBlockLayout(CodeGenModule &CGM,
+                                                const CGBlockInfo &blockInfo) {
+  llvm::Constant *nullPtr = 
     llvm::Constant::getNullValue(llvm::Type::getInt8PtrTy(VMContext));
+
   if (CGM.getLangOptions().getGCMode() == LangOptions::NonGC)
-    return NullPtr;
+    return nullPtr;
+
   bool hasUnion = false;
   SkipIvars.clear();
   IvarsInfo.clear();
@@ -1682,47 +1684,59 @@ llvm::Constant *CGObjCCommonMac::GCBlockLayout(CodeGen::CodeGenFunction &CGF,
   // __isa is the first field in block descriptor and must assume by runtime's
   // convention that it is GC'able.
   IvarsInfo.push_back(GC_IVAR(0, 1));
-  for (size_t i = 0; i < BlockLayout.size(); ++i) {
-    const Expr *E = BlockLayout[i];
-    const BlockDeclRefExpr *BDRE = dyn_cast<BlockDeclRefExpr>(E);
-    if (!BDRE)
+
+  const BlockDecl *blockDecl = blockInfo.getBlockDecl();
+
+  // Calculate the basic layout of the block structure.
+  const llvm::StructLayout *layout =
+    CGM.getTargetData().getStructLayout(blockInfo.StructureType);
+
+  // Ignore the optional 'this' capture: C++ objects are not assumed
+  // to be GC'ed.
+
+  // Walk the captured variables.
+  for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
+         ce = blockDecl->capture_end(); ci != ce; ++ci) {
+    const VarDecl *variable = ci->getVariable();
+    QualType type = variable->getType();
+
+    const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
+
+    // Ignore constant captures.
+    if (capture.isConstant()) continue;
+
+    uint64_t fieldOffset = layout->getElementOffset(capture.getIndex());
+
+    // __block variables are passed by their descriptor address.
+    if (ci->isByRef()) {
+      IvarsInfo.push_back(GC_IVAR(fieldOffset, /*size in words*/ 1));
       continue;
-    const ValueDecl *VD = BDRE->getDecl();
-    CharUnits Offset = CGF.BlockDecls[VD];
-    uint64_t FieldOffset = Offset.getQuantity();
-    QualType Ty = VD->getType();
-    assert(!Ty->isArrayType() && 
-           "Array block variable should have been caught");
-    if ((Ty->isRecordType() || Ty->isUnionType()) && !BDRE->isByRef()) {
-      BuildAggrIvarRecordLayout(Ty->getAs<RecordType>(),
-                                FieldOffset,
-                                true,
-                                hasUnion);
+    }
+
+    assert(!type->isArrayType() && "array variable should not be caught");
+    if (const RecordType *record = type->getAs<RecordType>()) {
+      BuildAggrIvarRecordLayout(record, fieldOffset, true, hasUnion);
       continue;
     }
       
-    Qualifiers::GC GCAttr = GetGCAttrTypeForType(CGM.getContext(), Ty);
-    unsigned FieldSize = CGM.getContext().getTypeSize(Ty);
-    // __block variables are passed by their descriptior address. So, size
-    // must reflect this.
-    if (BDRE->isByRef())
-      FieldSize = WordSizeInBits;
-    if (GCAttr == Qualifiers::Strong || BDRE->isByRef())
-      IvarsInfo.push_back(GC_IVAR(FieldOffset,
-                                  FieldSize / WordSizeInBits));
+    Qualifiers::GC GCAttr = GetGCAttrTypeForType(CGM.getContext(), type);
+    unsigned fieldSize = CGM.getContext().getTypeSize(type);
+
+    if (GCAttr == Qualifiers::Strong)
+      IvarsInfo.push_back(GC_IVAR(fieldOffset,
+                                  fieldSize / WordSizeInBits));
     else if (GCAttr == Qualifiers::GCNone || GCAttr == Qualifiers::Weak)
-      SkipIvars.push_back(GC_IVAR(FieldOffset,
-                                  FieldSize / ByteSizeInBits));
+      SkipIvars.push_back(GC_IVAR(fieldOffset,
+                                  fieldSize / ByteSizeInBits));
   }
   
   if (IvarsInfo.empty())
-    return NullPtr;
-  // Sort on byte position in case we encounterred a union nested in
-  // block variable type's aggregate type.
-  if (hasUnion && !IvarsInfo.empty())
-    std::sort(IvarsInfo.begin(), IvarsInfo.end());
-  if (hasUnion && !SkipIvars.empty())
-    std::sort(SkipIvars.begin(), SkipIvars.end());
+    return nullPtr;
+
+  // Sort on byte position; captures might not be allocated in order,
+  // and unions can do funny things.
+  llvm::array_pod_sort(IvarsInfo.begin(), IvarsInfo.end());
+  llvm::array_pod_sort(SkipIvars.begin(), SkipIvars.end());
   
   std::string BitMap;
   llvm::Constant *C = BuildIvarLayoutBitmap(BitMap);