Fix Mach-O unit tests breakage on Windows

[ruiu]

Summary

Mach-O normalized file reader assumes that the entire file is aligned
to a large boundary. If the in-memory file is not aligned properly, it will
abort with an assertion failure in read32/read64. This patch forces the
in-memory file for the unit test to be aligned at 64-byte boundary.

I found these tests are failing on Windows, but theoretically they could
fail on other platform.

[kledzik]

Funny. I just ran into this myself linking libc for arm64. Some of the .o files inside static archives are not 8-byte aligned, so the read64() is asserting. I think the read64() assert may be too aggressive. It may need to fallback to memcpy() for reading unaligned data, rather that asserting.

But this patch is goodness. Mach-O files should be at least 4 or 8 byte aligned, and the uint8_t[] does not guarantee that. Please commit this.

[ruiu]

Thanks. Committed as r221508.

unittests/MachOTests/MachONormalizedFileBinaryReaderTests.cpp

   return std::move(*r);
 }
 
+// The Mach-O object reader uses functions such as read32 or read64
+// which don't allow unaligned access. Our in-memory object file
+// needs to be aligned to a larger offset than uint8_t's.
+#if _MSC_VER
+#define FILEBYTES __declspec(align(64)) const uint8_t fileBytes[]
+#else
+#define FILEBYTES const uint8_t fileBytes[] __attribute__((aligned(64)))
+#endif
 
 TEST(BinaryReaderTest, empty_obj_x86_64) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
       0xcf, 0xfa, 0xed, 0xfe, 0x07, 0x00, 0x00, 0x01,
       0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
       0x01, 0x00, 0x00, 0x00, 0x98, 0x00, 0x00, 0x00,

 
 
 TEST(BinaryReaderTest, empty_obj_x86) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
       0xce, 0xfa, 0xed, 0xfe, 0x07, 0x00, 0x00, 0x00,
       0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
       0x01, 0x00, 0x00, 0x00, 0x7c, 0x00, 0x00, 0x00,

 
 
 TEST(BinaryReaderTest, empty_obj_ppc) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
       0xfe, 0xed, 0xfa, 0xce, 0x00, 0x00, 0x00, 0x12,
       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
       0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x7c,

 
 
 TEST(BinaryReaderTest, empty_obj_armv7) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
       0xce, 0xfa, 0xed, 0xfe, 0x0c, 0x00, 0x00, 0x00,
       0x09, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
       0x01, 0x00, 0x00, 0x00, 0x7c, 0x00, 0x00, 0x00,

 }
 
 TEST(BinaryReaderTest, empty_obj_x86_64_arm7) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
 #include "empty_obj_x86_armv7.txt"
   };
   std::unique_ptr<NormalizedFile> f =

 }
 
 TEST(BinaryReaderTest, hello_obj_x86_64) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
     0xCF, 0xFA, 0xED, 0xFE, 0x07, 0x00, 0x00, 0x01,
     0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
     0x03, 0x00, 0x00, 0x00, 0x50, 0x01, 0x00, 0x00,

 
 
 TEST(BinaryReaderTest, hello_obj_x86) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
     0xCE, 0xFA, 0xED, 0xFE, 0x07, 0x00, 0x00, 0x00,
     0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
     0x03, 0x00, 0x00, 0x00, 0x28, 0x01, 0x00, 0x00,

 
 
 TEST(BinaryReaderTest, hello_obj_armv7) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
     0xCE, 0xFA, 0xED, 0xFE, 0x0C, 0x00, 0x00, 0x00,
     0x09, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
     0x03, 0x00, 0x00, 0x00, 0x28, 0x01, 0x00, 0x00,

 
 
 TEST(BinaryReaderTest, hello_obj_ppc) {
-  const uint8_t fileBytes[] = {
+  FILEBYTES = {
     0xFE, 0xED, 0xFA, 0xCE, 0x00, 0x00, 0x00, 0x12,
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
     0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x01, 0x28,

   writeBinary(*f, "/tmp/foo.o");
 
 }
-