From a67abc83b73342fcb0cca58f36273a181273bc0c Mon Sep 17 00:00:00 2001
From: Jessica Paquette <jpaquette@apple.com>
Date: Tue, 26 Jun 2018 22:09:48 +0000
Subject: [MachineOutliner] Emit a warning when using -moutline on unsupported
 targets

Instead of just saying "flag unused", we should tell the user that the
outliner isn't (at least officially) supported for some given architecture.

This adds a warning that will state something like

The 'blah' architecture does not support -moutline; flag ignored

when we call -moutline with the 'blah' architecture.

Since the outliner is still mostly an AArch64 thing, any architecture
other than AArch64 will emit this warning.

llvm-svn: 335672
---
 clang/lib/Driver/ToolChains/Clang.cpp | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

(limited to 'clang/lib/Driver/ToolChains/Clang.cpp')

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 327fa6b57b5..1f08f303452 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -1476,19 +1476,6 @@ void Clang::AddAArch64TargetArgs(const ArgList &Args,
     else
       CmdArgs.push_back("-aarch64-enable-global-merge=true");
   }
-
-  if (Args.hasFlag(options::OPT_moutline, options::OPT_mno_outline, false)) {
-    CmdArgs.push_back("-mllvm");
-    CmdArgs.push_back("-enable-machine-outliner");
-
-    // The outliner shouldn't compete with linkers that dedupe linkonceodr
-    // functions in LTO. Enable that behaviour by default when compiling with
-    // LTO.
-    if (getToolChain().getDriver().isUsingLTO()) {
-      CmdArgs.push_back("-mllvm");
-      CmdArgs.push_back("-enable-linkonceodr-outlining");
-    }
-  }
 }
 
 void Clang::AddMIPSTargetArgs(const ArgList &Args,
@@ -4814,6 +4801,26 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                    options::OPT_fno_complete_member_pointers, false))
     CmdArgs.push_back("-fcomplete-member-pointers");
 
+  if (Args.hasFlag(options::OPT_moutline, options::OPT_mno_outline, false)) {
+    // We only support -moutline in AArch64 right now. If we're not compiling
+    // for AArch64, emit a warning and ignore the flag. Otherwise, add the
+    // proper mllvm flags.
+    if (Triple.getArch() != llvm::Triple::aarch64) {
+      D.Diag(diag::warn_drv_moutline_unsupported_opt) << Triple.getArchName();
+    } else {
+      CmdArgs.push_back("-mllvm");
+      CmdArgs.push_back("-enable-machine-outliner");
+
+      // The outliner shouldn't compete with linkers that dedupe linkonceodr
+      // functions in LTO. Enable that behaviour by default when compiling with
+      // LTO.
+      if (getToolChain().getDriver().isUsingLTO()) {
+        CmdArgs.push_back("-mllvm");
+        CmdArgs.push_back("-enable-linkonceodr-outlining");
+      }
+    }
+  }
+
   // Finally add the compile command to the compilation.
   if (Args.hasArg(options::OPT__SLASH_fallback) &&
       Output.getType() == types::TY_Object &&
-- 
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