Weak relaxing of the constraints on atomics in MemoryDependencyAnalysis

[oota-llvm.git] / lib / Object / ELFObjectFile.cpp

diff --git a/lib/Object/ELFObjectFile.cpp b/lib/Object/ELFObjectFile.cpp
index 663b84ec8b1f2d160b1e7074860a4305abfbd118..2e5e3c8836c42780143b42884dc1656ee9ab1151 100644 (file)
--- a/lib/Object/ELFObjectFile.cpp
+++ b/lib/Object/ELFObjectFile.cpp
@@ -11,30 +11,80 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Object/ELF.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Support/MathExtras.h"
 
 namespace llvm {
-
 using namespace object;
 
-// Creates an in-memory object-file by default: createELFObjectFile(Buffer)
-ObjectFile *ObjectFile::createELFObjectFile(MemoryBuffer *Object) {
-  std::pair<unsigned char, unsigned char> Ident = getElfArchType(Object);
-  error_code ec;
+ELFObjectFileBase::ELFObjectFileBase(unsigned int Type,
+                                     std::unique_ptr<MemoryBuffer> Source)
+    : ObjectFile(Type, std::move(Source)) {}
+
+ErrorOr<std::unique_ptr<ObjectFile>>
+ObjectFile::createELFObjectFile(std::unique_ptr<MemoryBuffer> &Obj) {
+  std::pair<unsigned char, unsigned char> Ident =
+      getElfArchType(Obj->getBuffer());
+  std::size_t MaxAlignment =
+    1ULL << countTrailingZeros(uintptr_t(Obj->getBufferStart()));
 
+  std::error_code EC;
+  std::unique_ptr<ObjectFile> R;
   if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB)
-    return new ELFObjectFile<support::little, false>(Object, ec);
+#if !LLVM_IS_UNALIGNED_ACCESS_FAST
+    if (MaxAlignment >= 4)
+      R.reset(new ELFObjectFile<ELFType<support::little, 4, false>>(
+          std::move(Obj), EC));
+    else
+#endif
+    if (MaxAlignment >= 2)
+      R.reset(new ELFObjectFile<ELFType<support::little, 2, false>>(
+          std::move(Obj), EC));
+    else
+      return object_error::parse_failed;
   else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB)
-    return new ELFObjectFile<support::big, false>(Object, ec);
+#if !LLVM_IS_UNALIGNED_ACCESS_FAST
+    if (MaxAlignment >= 4)
+      R.reset(new ELFObjectFile<ELFType<support::big, 4, false>>(std::move(Obj),
+                                                                 EC));
+    else
+#endif
+    if (MaxAlignment >= 2)
+      R.reset(new ELFObjectFile<ELFType<support::big, 2, false>>(std::move(Obj),
+                                                                 EC));
+    else
+      return object_error::parse_failed;
   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB)
-    return new ELFObjectFile<support::big, true>(Object, ec);
+#if !LLVM_IS_UNALIGNED_ACCESS_FAST
+    if (MaxAlignment >= 8)
+      R.reset(new ELFObjectFile<ELFType<support::big, 8, true>>(std::move(Obj),
+                                                                EC));
+    else
+#endif
+    if (MaxAlignment >= 2)
+      R.reset(new ELFObjectFile<ELFType<support::big, 2, true>>(std::move(Obj),
+                                                                EC));
+    else
+      return object_error::parse_failed;
   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
-    ELFObjectFile<support::little, true> *result =
-          new ELFObjectFile<support::little, true>(Object, ec);
-    return result;
+#if !LLVM_IS_UNALIGNED_ACCESS_FAST
+    if (MaxAlignment >= 8)
+      R.reset(new ELFObjectFile<ELFType<support::little, 8, true>>(
+          std::move(Obj), EC));
+    else
+#endif
+    if (MaxAlignment >= 2)
+      R.reset(new ELFObjectFile<ELFType<support::little, 2, true>>(
+          std::move(Obj), EC));
+    else
+      return object_error::parse_failed;
   }
+  else
+    llvm_unreachable("Buffer is not an ELF object file!");
 
-  report_fatal_error("Buffer is not an ELF object file!");
+  if (EC)
+    return EC;
+  return std::move(R);
 }
 
 } // end namespace llvm