uselistorder: -mllvm -preserve-bc-use-list-order => -emit-llvm-uselists

Stop relying on `cl::opt` to pass along the driver's decision to
preserve use-lists.  Create a new `-cc1` option called
`-emit-llvm-uselists` that does the right thing (when -emit-llvm-bc).
Note that despite its generic name, it *doesn't* do the right thing when
-emit-llvm (LLVM assembly) yet.  I'll hook that up soon.

This doesn't really change the behaviour of the driver.  The default is
still to preserve use-lists for `clang -emit-llvm` and `clang
-save-temps`, and nothing else.  But it stops relying on global state
(and also is a nicer interface for hackers using `clang -cc1`).

llvm-svn: 234962

3 files changed, 7 insertions, 5 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 705d0cc0ce6..a6d09f7b8c9 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -603,7 +603,7 @@ void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
 
   case Backend_EmitBC:
     getPerModulePasses()->add(
-        createBitcodeWriterPass(*OS, shouldPreserveBitcodeUseListOrder()));
+        createBitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists));
     break;
 
   case Backend_EmitLL:
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 2d2526c4bdf..fda410687c1 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -2683,10 +2683,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     // loading the bitcode up in 'opt' or 'llc' and running passes gives the
     // same result as running passes here.  For LTO, we don't need to preserve
     // the use-list order, since serialization to bitcode is part of the flow.
-    if (JA.getType() == types::TY_LLVM_BC) {
-      CmdArgs.push_back("-mllvm");
-      CmdArgs.push_back("-preserve-bc-uselistorder");
-    }
+    if (JA.getType() == types::TY_LLVM_BC)
+      CmdArgs.push_back("-emit-llvm-uselists");
   }
 
   // We normally speed up the clang process a bit by skipping destructors at
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 9632d4ea8c8..968f212dda9 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -405,6 +405,10 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
     // Default Dwarf version is 4 if we are generating debug information.
     Opts.DwarfVersion = 4;
 
+  if (const Arg *A =
+          Args.getLastArg(OPT_emit_llvm_uselists, OPT_no_emit_llvm_uselists))
+    Opts.EmitLLVMUseLists = A->getOption().getID() == OPT_emit_llvm_uselists;
+
   Opts.DisableLLVMOpts = Args.hasArg(OPT_disable_llvm_optzns);
   Opts.DisableRedZone = Args.hasArg(OPT_disable_red_zone);
   Opts.ForbidGuardVariables = Args.hasArg(OPT_fforbid_guard_variables);