Vendor import of clang trunk r130700:

http://llvm.org/svn/llvm-project/cfe/trunk@130700

1 files changed, 310 insertions, 0 deletions

diff --git a/lib/CodeGen/CGObjCRuntime.cpp b/lib/CodeGen/CGObjCRuntime.cpp
new file mode 100644
index 0000000..3d854d4
--- /dev/null
+++ b/lib/CodeGen/CGObjCRuntime.cpp
@@ -0,0 +1,310 @@
+//==- CGObjCRuntime.cpp - Interface to Shared Objective-C Runtime Features ==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This abstract class defines the interface for Objective-C runtime-specific
+// code generation.  It provides some concrete helper methods for functionality
+// shared between all (or most) of the Objective-C runtimes supported by clang.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CGObjCRuntime.h"
+
+#include "CGRecordLayout.h"
+#include "CodeGenModule.h"
+#include "CodeGenFunction.h"
+#include "CGCleanup.h"
+
+#include "clang/AST/RecordLayout.h"
+#include "clang/AST/StmtObjC.h"
+
+#include "llvm/Support/CallSite.h"
+
+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 && 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;
+  llvm::SmallVector<ObjCIvarDecl*, 16> Ivars;
+  CGM.getContext().ShallowCollectObjCIvars(Container, Ivars);
+  for (unsigned k = 0, e = Ivars.size(); k != e; ++k) {
+    if (Ivar == Ivars[k])
+      break;
+    ++Index;
+  }
+  assert(Index != Ivars.size() && "Ivar is not inside container!");
+  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, 0, 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();
+}
+
+LValue CGObjCRuntime::EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
+                                               const ObjCInterfaceDecl *OID,
+                                               llvm::Value *BaseValue,
+                                               const ObjCIvarDecl *Ivar,
+                                               unsigned CVRQualifiers,
+                                               llvm::Value *Offset) {
+  // Compute (type*) ( (char *) BaseValue + Offset)
+  const llvm::Type *I8Ptr = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
+  QualType IvarTy = Ivar->getType();
+  const llvm::Type *LTy = CGF.CGM.getTypes().ConvertTypeForMem(IvarTy);
+  llvm::Value *V = CGF.Builder.CreateBitCast(BaseValue, I8Ptr);
+  V = CGF.Builder.CreateInBoundsGEP(V, Offset, "add.ptr");
+  V = CGF.Builder.CreateBitCast(V, llvm::PointerType::getUnqual(LTy));
+
+  if (!Ivar->isBitField()) {
+    LValue LV = CGF.MakeAddrLValue(V, IvarTy);
+    LV.getQuals().addCVRQualifiers(CVRQualifiers);
+    return LV;
+  }
+
+  // We need to compute an access strategy for this bit-field. We are given the
+  // offset to the first byte in the bit-field, the sub-byte offset is taken
+  // from the original layout. We reuse the normal bit-field access strategy by
+  // treating this as an access to a struct where the bit-field is in byte 0,
+  // and adjust the containing type size as appropriate.
+  //
+  // FIXME: Note that currently we make a very conservative estimate of the
+  // alignment of the bit-field, because (a) it is not clear what guarantees the
+  // runtime makes us, and (b) we don't have a way to specify that the struct is
+  // at an alignment plus offset.
+  //
+  // 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.
+  const ASTRecordLayout &RL =
+    CGF.CGM.getContext().getASTObjCInterfaceLayout(OID);
+  uint64_t TypeSizeInBits = CGF.CGM.getContext().toBits(RL.getSize());
+  uint64_t FieldBitOffset = LookupFieldBitOffset(CGF.CGM, OID, 0, Ivar);
+  uint64_t BitOffset = FieldBitOffset % CGF.CGM.getContext().getCharWidth();
+  uint64_t ContainingTypeAlign = CGF.CGM.getContext().Target.getCharAlign();
+  uint64_t ContainingTypeSize = TypeSizeInBits - (FieldBitOffset - BitOffset);
+  uint64_t BitFieldSize =
+    Ivar->getBitWidth()->EvaluateAsInt(CGF.getContext()).getZExtValue();
+
+  // Allocate a new CGBitFieldInfo object to describe this access.
+  //
+  // FIXME: This is incredibly wasteful, these should be uniqued or part of some
+  // layout object. However, this is blocked on other cleanups to the
+  // Objective-C code, so for now we just live with allocating a bunch of these
+  // objects.
+  CGBitFieldInfo *Info = new (CGF.CGM.getContext()) CGBitFieldInfo(
+    CGBitFieldInfo::MakeInfo(CGF.CGM.getTypes(), Ivar, BitOffset, BitFieldSize,
+                             ContainingTypeSize, ContainingTypeAlign));
+
+  return LValue::MakeBitfield(V, *Info,
+                              IvarTy.getCVRQualifiers() | CVRQualifiers);
+}
+
+namespace {
+  struct CatchHandler {
+    const VarDecl *Variable;
+    const Stmt *Body;
+    llvm::BasicBlock *Block;
+    llvm::Value *TypeInfo;
+  };
+
+  struct CallObjCEndCatch : EHScopeStack::Cleanup {
+    CallObjCEndCatch(bool MightThrow, llvm::Value *Fn) :
+      MightThrow(MightThrow), Fn(Fn) {}
+    bool MightThrow;
+    llvm::Value *Fn;
+
+    void Emit(CodeGenFunction &CGF, bool IsForEH) {
+      if (!MightThrow) {
+        CGF.Builder.CreateCall(Fn)->setDoesNotThrow();
+        return;
+      }
+
+      CGF.EmitCallOrInvoke(Fn, 0, 0);
+    }
+  };
+}
+
+
+void CGObjCRuntime::EmitTryCatchStmt(CodeGenFunction &CGF,
+                                     const ObjCAtTryStmt &S,
+                                     llvm::Function *beginCatchFn,
+                                     llvm::Function *endCatchFn,
+                                     llvm::Function *exceptionRethrowFn) {
+  // Jump destination for falling out of catch bodies.
+  CodeGenFunction::JumpDest Cont;
+  if (S.getNumCatchStmts())
+    Cont = CGF.getJumpDestInCurrentScope("eh.cont");
+
+  CodeGenFunction::FinallyInfo FinallyInfo;
+  if (const ObjCAtFinallyStmt *Finally = S.getFinallyStmt())
+    FinallyInfo = CGF.EnterFinallyBlock(Finally->getFinallyBody(),
+                                        beginCatchFn,
+                                        endCatchFn,
+                                        exceptionRethrowFn);
+
+  llvm::SmallVector<CatchHandler, 8> Handlers;
+
+  // Enter the catch, if there is one.
+  if (S.getNumCatchStmts()) {
+    for (unsigned I = 0, N = S.getNumCatchStmts(); I != N; ++I) {
+      const ObjCAtCatchStmt *CatchStmt = S.getCatchStmt(I);
+      const VarDecl *CatchDecl = CatchStmt->getCatchParamDecl();
+
+      Handlers.push_back(CatchHandler());
+      CatchHandler &Handler = Handlers.back();
+      Handler.Variable = CatchDecl;
+      Handler.Body = CatchStmt->getCatchBody();
+      Handler.Block = CGF.createBasicBlock("catch");
+
+      // @catch(...) always matches.
+      if (!CatchDecl) {
+        Handler.TypeInfo = 0; // catch-all
+        // Don't consider any other catches.
+        break;
+      }
+
+      Handler.TypeInfo = GetEHType(CatchDecl->getType());
+    }
+
+    EHCatchScope *Catch = CGF.EHStack.pushCatch(Handlers.size());
+    for (unsigned I = 0, E = Handlers.size(); I != E; ++I)
+      Catch->setHandler(I, Handlers[I].TypeInfo, Handlers[I].Block);
+  }
+  
+  // Emit the try body.
+  CGF.EmitStmt(S.getTryBody());
+
+  // Leave the try.
+  if (S.getNumCatchStmts())
+    CGF.EHStack.popCatch();
+
+  // Remember where we were.
+  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
+
+  // Emit the handlers.
+  for (unsigned I = 0, E = Handlers.size(); I != E; ++I) {
+    CatchHandler &Handler = Handlers[I];
+
+    CGF.EmitBlock(Handler.Block);
+    llvm::Value *RawExn = CGF.Builder.CreateLoad(CGF.getExceptionSlot());
+
+    // Enter the catch.
+    llvm::Value *Exn = RawExn;
+    if (beginCatchFn) {
+      Exn = CGF.Builder.CreateCall(beginCatchFn, RawExn, "exn.adjusted");
+      cast<llvm::CallInst>(Exn)->setDoesNotThrow();
+    }
+
+    if (endCatchFn) {
+      // Add a cleanup to leave the catch.
+      bool EndCatchMightThrow = (Handler.Variable == 0);
+
+      CGF.EHStack.pushCleanup<CallObjCEndCatch>(NormalAndEHCleanup,
+                                                EndCatchMightThrow,
+                                                endCatchFn);
+    }
+
+    // Bind the catch parameter if it exists.
+    if (const VarDecl *CatchParam = Handler.Variable) {
+      const llvm::Type *CatchType = CGF.ConvertType(CatchParam->getType());
+      llvm::Value *CastExn = CGF.Builder.CreateBitCast(Exn, CatchType);
+
+      CGF.EmitAutoVarDecl(*CatchParam);
+      CGF.Builder.CreateStore(CastExn, CGF.GetAddrOfLocalVar(CatchParam));
+    }
+
+    CGF.ObjCEHValueStack.push_back(Exn);
+    CGF.EmitStmt(Handler.Body);
+    CGF.ObjCEHValueStack.pop_back();
+
+    // Leave the earlier cleanup.
+    if (endCatchFn) 
+      CGF.PopCleanupBlock();
+
+    CGF.EmitBranchThroughCleanup(Cont);
+  }  
+
+  // Go back to the try-statement fallthrough.
+  CGF.Builder.restoreIP(SavedIP);
+
+  // Pop out of the normal cleanup on the finally.
+  if (S.getFinallyStmt())
+    CGF.ExitFinallyBlock(FinallyInfo);
+
+  if (Cont.isValid())
+    CGF.EmitBlock(Cont.getBlock());
+}
+
+namespace {
+  struct CallSyncExit : EHScopeStack::Cleanup {
+    llvm::Value *SyncExitFn;
+    llvm::Value *SyncArg;
+    CallSyncExit(llvm::Value *SyncExitFn, llvm::Value *SyncArg)
+      : SyncExitFn(SyncExitFn), SyncArg(SyncArg) {}
+
+    void Emit(CodeGenFunction &CGF, bool IsForEHCleanup) {
+      CGF.Builder.CreateCall(SyncExitFn, SyncArg)->setDoesNotThrow();
+    }
+  };
+}
+
+void CGObjCRuntime::EmitAtSynchronizedStmt(CodeGenFunction &CGF,
+                                           const ObjCAtSynchronizedStmt &S,
+                                           llvm::Function *syncEnterFn,
+                                           llvm::Function *syncExitFn) {
+  // Evaluate the lock operand.  This should dominate the cleanup.
+  llvm::Value *SyncArg =
+    CGF.EmitScalarExpr(S.getSynchExpr());
+
+  // Acquire the lock.
+  SyncArg = CGF.Builder.CreateBitCast(SyncArg, syncEnterFn->getFunctionType()->getParamType(0));
+  CGF.Builder.CreateCall(syncEnterFn, SyncArg);
+
+  // Register an all-paths cleanup to release the lock.
+  CGF.EHStack.pushCleanup<CallSyncExit>(NormalAndEHCleanup, syncExitFn,
+      SyncArg);
+
+  // Emit the body of the statement.
+  CGF.EmitStmt(S.getSynchBody());
+
+  // Pop the lock-release cleanup.
+  CGF.PopCleanupBlock();
+}