ELF: Remove ELFT and LinkingContext template parameters from ELFReader.

Previously, ELFReader takes three template arguments: EFLT,
LinkingContextT and FileT. FileT is itself templated.
So it was a bit complicated. Maybe too much.

Most architectures don't actually need to be parameterized for ELFT.
For example, x86 is always ELF32LE and x86-64 is ELF64LE.
However, because ELFReader requires a ELFT argument, we needed
to parameterize a class even if not needed.

This patch removes the parameter from the class. So now we can
de-templatize such classes (I didn't do that in this patch, though).

This patch also removes ContextT parameter since it didn't have to be
passed as a template argument.

llvm-svn: 234853

1 files changed, 63 insertions, 0 deletions

diff --git a/lld/lib/ReaderWriter/ELF/FileCommon.cpp b/lld/lib/ReaderWriter/ELF/FileCommon.cpp
new file mode 100644
index 00000000000..e4a3e40282d
--- /dev/null
+++ b/lld/lib/ReaderWriter/ELF/FileCommon.cpp
@@ -0,0 +1,63 @@
+//===- lib/ReaderWriter/ELF/FileCommon.cpp --------------------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ELFFile.h"
+#include "FileCommon.h"
+
+using namespace llvm::ELF;
+
+namespace lld {
+namespace elf {
+
+template <>
+std::error_code checkCompatibility<ELF32LE>(unsigned char size,
+                                            unsigned char endian) {
+  if (size == ELFCLASS64)
+    return make_dynamic_error_code("ELF32 expected, but got ELF64");
+  if (endian == ELFDATA2MSB)
+    return make_dynamic_error_code(
+        "Little endian files are expected, but got a big endian file.");
+  return std::error_code();
+}
+
+template <>
+std::error_code checkCompatibility<ELF32BE>(unsigned char size,
+                                            unsigned char endian) {
+  if (size == ELFCLASS64)
+    return make_dynamic_error_code("ELF32 expected, but got ELF64");
+  if (endian == ELFDATA2LSB)
+    return make_dynamic_error_code(
+        "Big endian files are expected, but got a little endian file.");
+  return std::error_code();
+}
+
+template <>
+std::error_code checkCompatibility<ELF64LE>(unsigned char size,
+                                            unsigned char endian) {
+  if (size == ELFCLASS32)
+    return make_dynamic_error_code("ELF64 expected, but got ELF32");
+  if (endian == ELFDATA2MSB)
+    return make_dynamic_error_code(
+        "Little endian files are expected, but got a big endian file.");
+  return std::error_code();
+}
+
+template <>
+std::error_code checkCompatibility<ELF64BE>(unsigned char size,
+                                            unsigned char endian) {
+  if (size == ELFCLASS32)
+    return make_dynamic_error_code("ELF64 expected, but got ELF32");
+  if (endian == ELFDATA2LSB)
+    return make_dynamic_error_code(
+        "Big endian files are expected, but got a little endian file.");
+  return std::error_code();
+}
+
+} // end namespace elf
+} // end namespace lld