[CodeGen][ObjC] Fix GNU's encoding of bit-field ivars.

According to the documentation, when encoding a bit-field, GNU runtime
needs its starting position in addition to its type and size.

https://gcc.gnu.org/onlinedocs/gcc/Type-encoding.html

Prior to r297702, the starting position information was not being
encoded, which is incorrect, and after r297702, an assertion started to
fail because an ObjCIvarDecl was being passed to a function expecting a
FieldDecl.

This commit moves LookupFieldBitOffset to ASTContext and uses the
function to encode the starting position of bit-fields.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@306364 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/ASTContext.h b/include/clang/AST/ASTContext.h
index 4c379620ab2d5134073fb06b4b8a6a601aa55f1c..3b46d31458ceecc21f737a4d3d0e0f7a25f9e78c 100644 (file)
--- a/include/clang/AST/ASTContext.h
+++ b/include/clang/AST/ASTContext.h
@@ -2050,6 +2050,11 @@ public:
   /// Get the offset of a FieldDecl or IndirectFieldDecl, in bits.
   uint64_t getFieldOffset(const ValueDecl *FD) const;
 
+  /// Get the offset of an ObjCIvarDecl in bits.
+  uint64_t lookupFieldBitOffset(const ObjCInterfaceDecl *OID,
+                                const ObjCImplementationDecl *ID,
+                                const ObjCIvarDecl *Ivar) const;
+
   bool isNearlyEmpty(const CXXRecordDecl *RD) const;
 
   VTableContextBase *getVTableContext();

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index fabfdc9ef7e5a33699eb8d28d9c1b83d8eae9367..a2ff176df11f99cd4f7b429f81dfaad9bc367e25 100644 (file)
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -5990,9 +5990,19 @@ static void EncodeBitField(const ASTContext *Ctx, std::string& S,
   // compatibility with GCC, although providing it breaks anything that
   // actually uses runtime introspection and wants to work on both runtimes...
   if (Ctx->getLangOpts().ObjCRuntime.isGNUFamily()) {
-    const RecordDecl *RD = FD->getParent();
-    const ASTRecordLayout &RL = Ctx->getASTRecordLayout(RD);
-    S += llvm::utostr(RL.getFieldOffset(FD->getFieldIndex()));
+    uint64_t Offset;
+
+    if (const auto *IVD = dyn_cast<ObjCIvarDecl>(FD)) {
+      Offset = Ctx->lookupFieldBitOffset(IVD->getContainingInterface(), nullptr,
+                                         IVD);
+    } else {
+      const RecordDecl *RD = FD->getParent();
+      const ASTRecordLayout &RL = Ctx->getASTRecordLayout(RD);
+      Offset = RL.getFieldOffset(FD->getFieldIndex());
+    }
+
+    S += llvm::utostr(Offset);
+
     if (const EnumType *ET = T->getAs<EnumType>())
       S += ObjCEncodingForEnumType(Ctx, ET);
     else {

diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp
index cf981be0a4dde5b1bbd045bd2e43716dc8e592f7..c0b9cadca4227c7f55b60e7dab197c9b5107fe93 100644 (file)
--- a/lib/AST/RecordLayoutBuilder.cpp
+++ b/lib/AST/RecordLayoutBuilder.cpp
@@ -3073,6 +3073,41 @@ uint64_t ASTContext::getFieldOffset(const ValueDecl *VD) const {
   return OffsetInBits;
 }
 
+uint64_t ASTContext::lookupFieldBitOffset(const ObjCInterfaceDecl *OID,
+                                          const ObjCImplementationDecl *ID,
+                                          const ObjCIvarDecl *Ivar) const {
+  const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();
+
+  // FIXME: We should eliminate the need to have ObjCImplementationDecl passed
+  // in here; it should never be necessary because that should be the lexical
+  // decl context for the ivar.
+
+  // If we know have an implementation (and the ivar is in it) then
+  // look up in the implementation layout.
+  const ASTRecordLayout *RL;
+  if (ID && declaresSameEntity(ID->getClassInterface(), Container))
+    RL = &getASTObjCImplementationLayout(ID);
+  else
+    RL = &getASTObjCInterfaceLayout(Container);
+
+  // Compute field index.
+  //
+  // FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
+  // implemented. This should be fixed to get the information from the layout
+  // directly.
+  unsigned Index = 0;
+
+  for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin();
+       IVD; IVD = IVD->getNextIvar()) {
+    if (Ivar == IVD)
+      break;
+    ++Index;
+  }
+  assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!");
+
+  return RL->getFieldOffset(Index);
+}
+
 /// getObjCLayout - Get or compute information about the layout of the
 /// given interface.
 ///

diff --git a/lib/CodeGen/CGObjCRuntime.cpp b/lib/CodeGen/CGObjCRuntime.cpp
index b5599dad3096eb3207abef627ae9492bc530b164..4cfddcb107cb361f5d347cde517e93da34454846 100644 (file)
--- a/lib/CodeGen/CGObjCRuntime.cpp
+++ b/lib/CodeGen/CGObjCRuntime.cpp
@@ -26,61 +26,27 @@
 using namespace clang;
 using namespace CodeGen;
 
-static uint64_t LookupFieldBitOffset(CodeGen::CodeGenModule &CGM,
-                                     const ObjCInterfaceDecl *OID,
-                                     const ObjCImplementationDecl *ID,
-                                     const ObjCIvarDecl *Ivar) {
-  const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();
-
-  // FIXME: We should eliminate the need to have ObjCImplementationDecl passed
-  // in here; it should never be necessary because that should be the lexical
-  // decl context for the ivar.
-
-  // If we know have an implementation (and the ivar is in it) then
-  // look up in the implementation layout.
-  const ASTRecordLayout *RL;
-  if (ID && declaresSameEntity(ID->getClassInterface(), Container))
-    RL = &CGM.getContext().getASTObjCImplementationLayout(ID);
-  else
-    RL = &CGM.getContext().getASTObjCInterfaceLayout(Container);
-
-  // Compute field index.
-  //
-  // FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
-  // implemented. This should be fixed to get the information from the layout
-  // directly.
-  unsigned Index = 0;
-
-  for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin(); 
-       IVD; IVD = IVD->getNextIvar()) {
-    if (Ivar == IVD)
-      break;
-    ++Index;
-  }
-  assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!");
-
-  return RL->getFieldOffset(Index);
-}
-
 uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
                                               const ObjCInterfaceDecl *OID,
                                               const ObjCIvarDecl *Ivar) {
-  return LookupFieldBitOffset(CGM, OID, nullptr, Ivar) /
-    CGM.getContext().getCharWidth();
+  return CGM.getContext().lookupFieldBitOffset(OID, nullptr, Ivar) /
+         CGM.getContext().getCharWidth();
 }
 
 uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
                                               const ObjCImplementationDecl *OID,
                                               const ObjCIvarDecl *Ivar) {
-  return LookupFieldBitOffset(CGM, OID->getClassInterface(), OID, Ivar) / 
-    CGM.getContext().getCharWidth();
+  return CGM.getContext().lookupFieldBitOffset(OID->getClassInterface(), OID,
+                                               Ivar) /
+         CGM.getContext().getCharWidth();
 }
 
 unsigned CGObjCRuntime::ComputeBitfieldBitOffset(
     CodeGen::CodeGenModule &CGM,
     const ObjCInterfaceDecl *ID,
     const ObjCIvarDecl *Ivar) {
-  return LookupFieldBitOffset(CGM, ID, ID->getImplementation(), Ivar);
+  return CGM.getContext().lookupFieldBitOffset(ID, ID->getImplementation(),
+                                               Ivar);
 }
 
 LValue CGObjCRuntime::EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
@@ -119,7 +85,8 @@ LValue CGObjCRuntime::EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
   // Note, there is a subtle invariant here: we can only call this routine on
   // non-synthesized ivars but we may be called for synthesized ivars.  However,
   // a synthesized ivar can never be a bit-field, so this is safe.
-  uint64_t FieldBitOffset = LookupFieldBitOffset(CGF.CGM, OID, nullptr, Ivar);
+  uint64_t FieldBitOffset =
+      CGF.CGM.getContext().lookupFieldBitOffset(OID, nullptr, Ivar);
   uint64_t BitOffset = FieldBitOffset % CGF.CGM.getContext().getCharWidth();
   uint64_t AlignmentBits = CGF.CGM.getTarget().getCharAlign();
   uint64_t BitFieldSize = Ivar->getBitWidthValue(CGF.getContext());

diff --git a/test/CodeGenObjC/ivar-type-encoding.m b/test/CodeGenObjC/ivar-type-encoding.m
index ffa5e0d7af0d1b6f7701bf0029fb20d16b5161f7..d3afdc5f1188becb961529260116316134fe70b6 100644 (file)
--- a/test/CodeGenObjC/ivar-type-encoding.m
+++ b/test/CodeGenObjC/ivar-type-encoding.m
@@ -33,3 +33,19 @@ int main() {
 // CHECK: @1 = private unnamed_addr constant [12 x i8] c"@\22NSString\22\00"
 // CHECK: @2 = private unnamed_addr constant [9 x i8] c"_intIvar\00"
 // CHECK: @3 = private unnamed_addr constant [2 x i8] c"i\00"
+
+@interface Class1 {
+  int : 3;
+  short : 2;
+  long long ll;
+  char : 1;
+}
+@end
+
+@implementation Class1
+@end
+
+// CHECK: @{{.*}} = private unnamed_addr constant [5 x i8] c"b0i3\00"
+// CHECK: @{{.*}} = private unnamed_addr constant [5 x i8] c"b3s2\00"
+// CHECK: @{{.*}} = private unnamed_addr constant [2 x i8] c"q\00"
+// CHECK: @{{.*}} = private unnamed_addr constant [7 x i8] c"b128c1\00"