llvm-mc: Add a -mc-relax-all option, which relaxes every fixup. We always need
exactly two passes in that case, and don't ever need to recompute any layout,
so this is a nice baseline for relaxation performance.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99563 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index 0e183b0..6dce5cc 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -55,6 +55,9 @@
 OutputAsmVariant("output-asm-variant",
                  cl::desc("Syntax variant to use for output printing"));
 
+static cl::opt<bool>
+RelaxAll("mc-relax-all", cl::desc("Relax all fixups"));
+
 enum OutputFileType {
   OFT_Null,
   OFT_AssemblyFile,
@@ -298,7 +301,7 @@
     assert(FileType == OFT_ObjectFile && "Invalid file type!");
     CE.reset(TheTarget->createCodeEmitter(*TM, Ctx));
     TAB.reset(TheTarget->createAsmBackend(TripleName));
-    Str.reset(createMachOStreamer(Ctx, *TAB, *Out, CE.get()));
+    Str.reset(createMachOStreamer(Ctx, *TAB, *Out, CE.get(), RelaxAll));
   }
 
   AsmParser Parser(SrcMgr, Ctx, *Str.get(), *MAI);