6 files changed, 23 insertions, 4 deletions
diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index 6525d24d18c..172424e1e30 100644
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -200,6 +200,8 @@ def mms_bitfields : Flag<"-mms-bitfields">,
   HelpText<"Set the default structure layout to be compatible with the Microsoft compiler standard.">;
 def mstackrealign : Flag<"-mstackrealign">,
   HelpText<"Force realign the stack at entry to every function.">;
+def mstack_alignment : Joined<"-mstack-alignment=">,
+  HelpText<"Set the stack alignment">;
 def mlink_bitcode_file : Separate<"-mlink-bitcode-file">,
   HelpText<"Link the given bitcode file before performing optimizations.">;
 def O : Joined<"-O">, HelpText<"Optimization level">;
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 470ca5716a9..b4f04b63646 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -571,6 +571,7 @@ def mllvm : Separate<"-mllvm">;
 def mmacosx_version_min_EQ : Joined<"-mmacosx-version-min=">, Group<m_Group>;
 def mms_bitfields : Flag<"-mms-bitfields">, Group<m_Group>;
 def mstackrealign : Flag<"-mstackrealign">, Group<m_Group>;
+def mstack_alignment : Joined<"-mstack-alignment=">, Group<m_Group>;
 def mmmx : Flag<"-mmmx">, Group<m_x86_Features_Group>;
 def mno_3dnowa : Flag<"-mno-3dnowa">, Group<m_x86_Features_Group>;
 def mno_3dnow : Flag<"-mno-3dnow">, Group<m_x86_Features_Group>;
diff --git a/clang/include/clang/Frontend/CodeGenOptions.h b/clang/include/clang/Frontend/CodeGenOptions.h
index 9962ea8cf92..091246703cc 100644
--- a/clang/include/clang/Frontend/CodeGenOptions.h
+++ b/clang/include/clang/Frontend/CodeGenOptions.h
@@ -105,6 +105,11 @@ public:
   unsigned VerifyModule      : 1; /// Control whether the module should be run
                                   /// through the LLVM Verifier.
 
+  unsigned RealignStack       : 1; /// Controls whether stack frame should be
+                                  /// readjusted to the desired alignment.
+  unsigned StackAlignment;        /// Overrides default stack alignment,
+                                  /// if not 0.
+
   /// The code model to use (-mcmodel).
   std::string CodeModel;
 
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index f194c238b30..3bc57e767c3 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -289,6 +289,11 @@ bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
 
   llvm::TargetOptions Options;
 
+  if (CodeGenOpts.RealignStack)
+    Options.RealignStack = true;
+  if (CodeGenOpts.StackAlignment)
+    Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
+
   // Set frame pointer elimination mode.
   if (!CodeGenOpts.DisableFPElim) {
     Options.NoFramePointerElim = false;
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index eed1c828cbc..074be43fdb4 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1796,10 +1796,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(Args.MakeArgString(Twine(StackProtectorLevel)));
   }
 
-  // Translate -mstackrealign
-  if (Args.hasArg(options::OPT_mstackrealign)) {
-    CmdArgs.push_back("-backend-option");
-    CmdArgs.push_back("-force-align-stack");
+  if (Args.hasArg(options::OPT_mstackrealign))
+    CmdArgs.push_back("-mstackrealign");
+  if (Args.hasArg(options::OPT_mstack_alignment)) {
+    StringRef alignment = Args.getLastArgValue(options::OPT_mstack_alignment);
+    CmdArgs.push_back(Args.MakeArgString("-mstack-alignment=" + alignment));
   }
 
   // Forward -f options with positive and negative forms; we translate
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 6b5c8cf5b56..b89bf0808c9 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1114,6 +1114,11 @@ static void ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.CoverageFile = Args.getLastArgValue(OPT_coverage_file);
   Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
   Opts.LinkBitcodeFile = Args.getLastArgValue(OPT_mlink_bitcode_file);
+  Opts.RealignStack = Args.hasArg(OPT_mstackrealign);
+  if (Arg *A = Args.getLastArg(OPT_mstack_alignment)) {
+    StringRef Val = A->getValue(Args);
+    Val.getAsInteger(10, Opts.StackAlignment);
+  }
 
   if (Arg *A = Args.getLastArg(OPT_fobjc_dispatch_method_EQ)) {
     StringRef Name = A->getValue(Args);