[llvm] 53b3873 - [Support][unittests] Enforce alignment in ConvertUTFTest

[Rainer Orth via llvm-commits]

Author: Rainer Orth
Date: 2020-10-07T09:08:41+02:00
New Revision: 53b3873cf428fd78f1d92504cc20adf11181ead7

URL: https://github.com/llvm/llvm-project/commit/53b3873cf428fd78f1d92504cc20adf11181ead7
DIFF: https://github.com/llvm/llvm-project/commit/53b3873cf428fd78f1d92504cc20adf11181ead7.diff

LOG: [Support][unittests] Enforce alignment in ConvertUTFTest

`LLVM-Unit :: Support/./SupportTests/ConvertUTFTest.ConvertUTF16LittleEndianToUTF8String`
`FAIL`s on Solaris/sparcv9:

In `llvm/lib/Support/ConvertUTFWrapper.cpp` (`convertUTF16ToUTF8String`)
the `SrcBytes` arg is reinterpreted/accessed as `UTF16` (`unsigned short`,
which requires 2-byte alignment on strict-alignment targets like Sparc)
without anything guaranteeing the alignment, so the access yields a
`SIGBUS`.

This patch avoids this by enforcing the required alignment in the callers.

Tested on `sparcv9-sun-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D88824

Added: 
    

Modified: 
    llvm/lib/Support/ConvertUTFWrapper.cpp
    llvm/unittests/Support/ConvertUTFTest.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Support/ConvertUTFWrapper.cpp b/llvm/lib/Support/ConvertUTFWrapper.cpp
index 6ec567882ea6..d8d46712a593 100644
--- a/llvm/lib/Support/ConvertUTFWrapper.cpp
+++ b/llvm/lib/Support/ConvertUTFWrapper.cpp
@@ -97,6 +97,8 @@ bool convertUTF16ToUTF8String(ArrayRef<char> SrcBytes, std::string &Out) {
   const UTF16 *Src = reinterpret_cast<const UTF16 *>(SrcBytes.begin());
   const UTF16 *SrcEnd = reinterpret_cast<const UTF16 *>(SrcBytes.end());
 
+  assert((uintptr_t)Src % sizeof(UTF16) == 0);
+
   // Byteswap if necessary.
   std::vector<UTF16> ByteSwapped;
   if (Src[0] == UNI_UTF16_BYTE_ORDER_MARK_SWAPPED) {

diff  --git a/llvm/unittests/Support/ConvertUTFTest.cpp b/llvm/unittests/Support/ConvertUTFTest.cpp
index 83019722332d..b689e688f720 100644
--- a/llvm/unittests/Support/ConvertUTFTest.cpp
+++ b/llvm/unittests/Support/ConvertUTFTest.cpp
@@ -16,7 +16,7 @@ using namespace llvm;
 
 TEST(ConvertUTFTest, ConvertUTF16LittleEndianToUTF8String) {
   // Src is the look of disapproval.
-  static const char Src[] = "\xff\xfe\xa0\x0c_\x00\xa0\x0c";
+  alignas(UTF16) static const char Src[] = "\xff\xfe\xa0\x0c_\x00\xa0\x0c";
   ArrayRef<char> Ref(Src, sizeof(Src) - 1);
   std::string Result;
   bool Success = convertUTF16ToUTF8String(Ref, Result);
@@ -27,7 +27,7 @@ TEST(ConvertUTFTest, ConvertUTF16LittleEndianToUTF8String) {
 
 TEST(ConvertUTFTest, ConvertUTF16BigEndianToUTF8String) {
   // Src is the look of disapproval.
-  static const char Src[] = "\xfe\xff\x0c\xa0\x00_\x0c\xa0";
+  alignas(UTF16) static const char Src[] = "\xfe\xff\x0c\xa0\x00_\x0c\xa0";
   ArrayRef<char> Ref(Src, sizeof(Src) - 1);
   std::string Result;
   bool Success = convertUTF16ToUTF8String(Ref, Result);