Rebased PNaCl localmods in LLVM to 223109

lib/Analysis/NaCl/PNaClABIProps.cpp

+//===- PNaClABIProps.cpp - Verify PNaCl ABI Function Rules ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Verify function-level PNaCl ABI properties, at the construct level.
+//
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/NaCl.h"
+#include "llvm/Analysis/NaCl/PNaClABIProps.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Metadata.h"
+
+using namespace llvm;
+
+bool PNaClABIProps::isWhitelistedMetadata(unsigned MDKind) {
+  return MDKind == LLVMContext::MD_dbg && PNaClABIAllowDebugMetadata;
+}
+
+bool PNaClABIProps::isWhitelistedMetadata(const NamedMDNode *MD) {
+  return PNaClABIAllowDebugMetadata &&
+         (MD->getName().startswith("llvm.dbg.") ||
+          // "Debug Info Version" is in llvm.module.flags.
+          MD->getName().equals("llvm.module.flags"));
+}
+
+bool PNaClABIProps::
+isAllowedAlignment(const DataLayout *DL, uint64_t Alignment,
+                   const Type *Ty) {
+  // Non-atomic integer operations must always use "align 1", since we do not
+  // want the backend to generate code with non-portable undefined behaviour
+  // (such as misaligned access faults) if user code specifies "align 4" but
+  // uses a misaligned pointer.  As a concession to performance, we allow larger
+  // alignment values for floating point types, and we only allow vectors to be
+  // aligned by their element's size.
+  //
+  // TODO(jfb) Allow vectors to be marked as align == 1. This requires proper
+  //           testing on each supported ISA, and is probably not as common as
+  //           align == elemsize.
+  //
+  // To reduce the set of alignment values that need to be encoded in pexes, we
+  // disallow other alignment values.  We require alignments to be explicit by
+  // disallowing Alignment == 0.
+  if (Alignment > std::numeric_limits<uint64_t>::max() / CHAR_BIT)
+    return false; // No overflow assumed below.
+  else if (const VectorType *VTy = dyn_cast<VectorType>(Ty))
+    return !VTy->getElementType()->isIntegerTy(1) &&
+           (Alignment * CHAR_BIT ==
+            DL->getTypeSizeInBits(VTy->getElementType()));
+  else
+    return Alignment == 1 ||
+           (Ty->isDoubleTy() && Alignment == 8) ||
+           (Ty->isFloatTy() && Alignment == 4);
+}
+
+const char *PNaClABIProps::CallingConvName(CallingConv::ID CallingConv) {
+  // TODO(kschimpf): Add more calling conventions.
+  switch (CallingConv) {
+  case CallingConv::C:                return "ccc";
+  case CallingConv::Fast:             return "fastcc";
+  case CallingConv::Cold:             return "cold";
+  default:
+    return "unknown";
+  }
+}
+
+const char *PNaClABIProps::LinkageName(GlobalValue::LinkageTypes LT) {
+  // This logic is taken from PrintLinkage in lib/IR/AsmWriter.cpp
+  switch (LT) {
+  case GlobalValue::ExternalLinkage:      return "external";
+  case GlobalValue::PrivateLinkage:       return "private";
+  case GlobalValue::InternalLinkage:      return "internal";
+  case GlobalValue::LinkOnceAnyLinkage:   return "linkonce";
+  case GlobalValue::LinkOnceODRLinkage:   return "linkonce_odr";
+  case GlobalValue::WeakAnyLinkage:       return "weak";
+  case GlobalValue::WeakODRLinkage:       return "weak_odr";
+  case GlobalValue::CommonLinkage:        return "common";
+  case GlobalValue::AppendingLinkage:     return "appending";
+  case GlobalValue::ExternalWeakLinkage:  return "extern_weak";
+  case GlobalValue::AvailableExternallyLinkage:
+    return "available_externally";
+  }
+  llvm_unreachable("unhandled GlobalValue::LinkageTypes");
+}
+
+bool PNaClABIProps::isValidGlobalLinkage(GlobalValue::LinkageTypes Linkage) {
+  switch (Linkage) {
+    case GlobalValue::ExternalLinkage:
+      return true;
+    case GlobalValue::InternalLinkage:
+      return true;
+    default:
+      return false;
+  }
+}