Add an -mattr option to the gold plugin to support subtarget features in LTO

This adds support for an -mattr option to the gold plugin and to llvm-lto. This
allows the caller to specify details of the subtarget architecture, like +aes,
or +ssse3 on x86.  Note that this requires a change to the include/llvm-c/lto.h
interface: it adds a function lto_codegen_set_attr and it increments the
version of the interface.

llvm-svn: 207279

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/tools/llvm-lto/llvm-lto.cpp b/llvm/tools/llvm-lto/llvm-lto.cpp
index 1a92bf4f0ea..678e4db08f3 100644
--- a/llvm/tools/llvm-lto/llvm-lto.cpp
+++ b/llvm/tools/llvm-lto/llvm-lto.cpp
@@ -143,6 +143,16 @@ int main(int argc, char **argv) {
   for (unsigned i = 0; i < KeptDSOSyms.size(); ++i)
     CodeGen.addMustPreserveSymbol(KeptDSOSyms[i].c_str());
 
+  std::string attrs;
+  for (unsigned i = 0; i < MAttrs.size(); ++i) {
+    if (i > 0)
+      attrs.append(",");
+    attrs.append(MAttrs[i]);
+  }
+
+  if (!attrs.empty())
+    CodeGen.setAttr(attrs.c_str());
+
   if (!OutputFilename.empty()) {
     size_t len = 0;
     std::string ErrorInfo;