COFF: Align DLL import thunks on 16-byte boundaries.

llvm-svn: 240806

2 files changed, 7 insertions, 1 deletions

diff --git a/lld/COFF/Chunks.cpp b/lld/COFF/Chunks.cpp
index c5cf80ec7758..aa2c0be3ef51 100644
--- a/lld/COFF/Chunks.cpp
+++ b/lld/COFF/Chunks.cpp
@@ -216,6 +216,12 @@ void StringChunk::writeTo(uint8_t *Buf) {
   memcpy(Buf + FileOff, Str.data(), Str.size());
 }
 
+ImportThunkChunk::ImportThunkChunk(Defined *S) : ImpSymbol(S) {
+  // Intel Optimization Manual says that all branch targets
+  // should be 16-byte aligned. MSVC linker does this too.
+  Align = 16;
+}
+
 void ImportThunkChunk::writeTo(uint8_t *Buf) {
   memcpy(Buf + FileOff, ImportThunkData, sizeof(ImportThunkData));
   // The first two bytes is a JMP instruction. Fill its operand.
diff --git a/lld/COFF/Chunks.h b/lld/COFF/Chunks.h
index d44c02550836..37a6003cf8ec 100644
--- a/lld/COFF/Chunks.h
+++ b/lld/COFF/Chunks.h
@@ -198,7 +198,7 @@ static const uint8_t ImportThunkData[] = {
 // contents will be a JMP instruction to some __imp_ symbol.
 class ImportThunkChunk : public Chunk {
 public:
-  explicit ImportThunkChunk(Defined *S) : ImpSymbol(S) {}
+  explicit ImportThunkChunk(Defined *ImpSymbol);
   size_t getSize() const override { return sizeof(ImportThunkData); }
   void writeTo(uint8_t *Buf) override;