Driver: Support invoking Clang on .ll or .bc inputs.
 - We actually pretend that we have two separate types for LLVM assembly/bitcode because we need to use the standard suffixes with LTO ('clang -O4 -c t.c' should generate 't.o').

It is now possible to do something like:
  $ clang -emit-llvm -S t.c -o t.ll ... assorted other compile flags ...
  $ clang -c t.ll -o t.o ... assorted other compile flags ...
and expect that the output will be almost* identical to:
  $ clang -c t.c -o t.o ... assorted other compile flags ...
because all the target settings (default CPU, target features, etc.) will all be initialized properly by the driver/frontend.

*: This isn't perfect yet, because in practice we will end up running the optimization passes twice. It's possible to get something equivalent out with a well placed -mllvm -disable-llvm-optzns, but I'm still thinking about the cleanest way to solve this problem more generally.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@105584 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index cae2243..90333bd 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -797,7 +797,7 @@
     } else if (Args.hasArg(options::OPT_emit_llvm) ||
                Args.hasArg(options::OPT_flto) || HasO4) {
       types::ID Output =
-        Args.hasArg(options::OPT_S) ? types::TY_LLVMAsm : types::TY_LLVMBC;
+        Args.hasArg(options::OPT_S) ? types::TY_LTO_IR : types::TY_LTO_BC;
       return new CompileJobAction(Input, Output);
     } else {
       return new CompileJobAction(Input, types::TY_PP_Asm);
@@ -1263,8 +1263,8 @@
 
   // Always use clang for precompiling, AST generation, and rewriting,
   // regardless of archs.
-  if (isa<PrecompileJobAction>(JA) || JA.getType() == types::TY_AST ||
-      JA.getType() == types::TY_RewrittenObjC)
+  if (isa<PrecompileJobAction>(JA) ||
+      types::isOnlyAcceptedByClang(JA.getType()))
     return true;
 
   // Finally, don't use clang if this isn't one of the user specified archs to
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 4ab32ed..0556907 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -792,9 +792,11 @@
 
     if (JA.getType() == types::TY_Nothing) {
       CmdArgs.push_back("-fsyntax-only");
-    } else if (JA.getType() == types::TY_LLVMAsm) {
+    } else if (JA.getType() == types::TY_LLVM_IR ||
+               JA.getType() == types::TY_LTO_IR) {
       CmdArgs.push_back("-emit-llvm");
-    } else if (JA.getType() == types::TY_LLVMBC) {
+    } else if (JA.getType() == types::TY_LLVM_BC ||
+               JA.getType() == types::TY_LTO_BC) {
       CmdArgs.push_back("-emit-llvm-bc");
     } else if (JA.getType() == types::TY_PP_Asm) {
       CmdArgs.push_back("-S");
@@ -1634,7 +1636,8 @@
     const InputInfo &II = *it;
 
     // Don't try to pass LLVM or AST inputs to a generic gcc.
-    if (II.getType() == types::TY_LLVMBC)
+    if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
+        II.getType() == types::TY_LLVM_BC || II.getType() == types::TY_LTO_BC)
       D.Diag(clang::diag::err_drv_no_linker_llvm_support)
         << getToolChain().getTripleString();
     else if (II.getType() == types::TY_AST)
@@ -1676,7 +1679,8 @@
   const Driver &D = getToolChain().getDriver();
 
   // If -flto, etc. are present then make sure not to force assembly output.
-  if (JA.getType() == types::TY_LLVMBC)
+  if (JA.getType() == types::TY_LLVM_IR || JA.getType() == types::TY_LTO_IR ||
+      JA.getType() == types::TY_LLVM_BC || JA.getType() == types::TY_LTO_BC)
     CmdArgs.push_back("-c");
   else {
     if (JA.getType() != types::TY_PP_Asm)
@@ -2083,9 +2087,11 @@
     D.Diag(clang::diag::err_drv_argument_only_allowed_with)
       << A->getAsString(Args) << "-E";
 
-  if (Output.getType() == types::TY_LLVMAsm)
+  if (JA.getType() == types::TY_LLVM_IR ||
+      JA.getType() == types::TY_LTO_IR)
     CmdArgs.push_back("-emit-llvm");
-  else if (Output.getType() == types::TY_LLVMBC)
+  else if (JA.getType() == types::TY_LLVM_BC ||
+           JA.getType() == types::TY_LTO_BC)
     CmdArgs.push_back("-emit-llvm-bc");
   else if (Output.getType() == types::TY_AST)
     D.Diag(clang::diag::err_drv_no_ast_support)
@@ -2679,7 +2685,8 @@
     const InputInfo &II = *it;
 
     // Don't try to pass LLVM inputs to a generic gcc.
-    if (II.getType() == types::TY_LLVMBC)
+    if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
+        II.getType() == types::TY_LLVM_BC || II.getType() == types::TY_LTO_BC)
       D.Diag(clang::diag::err_drv_no_linker_llvm_support)
         << getToolChain().getTripleString();
 
@@ -2809,7 +2816,8 @@
     const InputInfo &II = *it;
 
     // Don't try to pass LLVM inputs to a generic gcc.
-    if (II.getType() == types::TY_LLVMBC)
+    if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
+        II.getType() == types::TY_LLVM_BC || II.getType() == types::TY_LTO_BC)
       D.Diag(clang::diag::err_drv_no_linker_llvm_support)
         << getToolChain().getTripleString();
 
@@ -2947,7 +2955,8 @@
     const InputInfo &II = *it;
 
     // Don't try to pass LLVM inputs to a generic gcc.
-    if (II.getType() == types::TY_LLVMBC)
+    if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
+        II.getType() == types::TY_LLVM_BC || II.getType() == types::TY_LTO_BC)
       D.Diag(clang::diag::err_drv_no_linker_llvm_support)
         << getToolChain().getTripleString();
 
@@ -3100,7 +3109,8 @@
     const InputInfo &II = *it;
 
     // Don't try to pass LLVM inputs to a generic gcc.
-    if (II.getType() == types::TY_LLVMBC)
+    if (II.getType() == types::TY_LLVM_IR || II.getType() == types::TY_LTO_IR ||
+        II.getType() == types::TY_LLVM_BC || II.getType() == types::TY_LTO_BC)
       D.Diag(clang::diag::err_drv_no_linker_llvm_support)
         << getToolChain().getTripleString();
 
diff --git a/lib/Driver/Types.cpp b/lib/Driver/Types.cpp
index 8857fb1..752a881 100644
--- a/lib/Driver/Types.cpp
+++ b/lib/Driver/Types.cpp
@@ -86,6 +86,20 @@
   case TY_CXXHeader: case TY_PP_CXXHeader:
   case TY_ObjCXXHeader: case TY_PP_ObjCXXHeader:
   case TY_AST:
+  case TY_LLVM_IR: case TY_LLVM_BC:
+    return true;
+  }
+}
+
+bool types::isOnlyAcceptedByClang(ID Id) {
+  switch (Id) {
+  default:
+    return false;
+
+  case TY_AST:
+  case TY_LLVM_IR:
+  case TY_LLVM_BC:
+  case TY_RewrittenObjC:
     return true;
   }
 }
@@ -132,11 +146,13 @@
            .Case("ii", TY_PP_CXX)
            .Case("mi", TY_PP_ObjC)
            .Case("mm", TY_ObjCXX)
+           .Case("bc", TY_LLVM_BC)
            .Case("cc", TY_CXX)
            .Case("CC", TY_CXX)
            .Case("cl", TY_CL)
            .Case("cp", TY_CXX)
            .Case("hh", TY_CXXHeader)
+           .Case("ll", TY_LLVM_IR)
            .Case("hpp", TY_CXXHeader)
            .Case("ads", TY_Ada)
            .Case("adb", TY_Ada)