[driver] Add a -mstrict-align compiler option for ARM targets.

rdar://12340498

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@167619 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 8 insertions, 0 deletions

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 2ace8f386b..af432a3bfb 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -789,6 +789,8 @@ def mstackrealign : Flag<["-"], "mstackrealign">, Group<m_Group>, Flags<[CC1Opti
   HelpText<"Force realign the stack at entry to every function.">;
 def mstack_alignment : Joined<["-"], "mstack-alignment=">, Group<m_Group>, Flags<[CC1Option]>,
   HelpText<"Set the stack alignment">;
+def mstrict_align : Flag<["-"], "mstrict-align">, Group<m_Group>, Flags<[CC1Option]>,
+  HelpText<"Force all memory accesses to be aligned. (ARM only)">;
 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/include/clang/Frontend/CodeGenOptions.def b/include/clang/Frontend/CodeGenOptions.def
index 558e6f1111..3df0b2fa7d 100644
--- a/include/clang/Frontend/CodeGenOptions.def
+++ b/include/clang/Frontend/CodeGenOptions.def
@@ -100,6 +100,7 @@ CODEGENOPT(VerifyModule      , 1, 1) ///< Control whether the module should be r
 
 CODEGENOPT(StackRealignment  , 1, 0) ///< Control whether to permit stack
                                      ///< realignment.
+CODEGENOPT(StrictAlign       , 1, 0) ///< Force all memory accesses to be aligned.
 CODEGENOPT(UseInitArray      , 1, 0) ///< Control whether to use .init_array or
                                      ///< .ctors.
 VALUE_CODEGENOPT(StackAlignment    , 32, 0) ///< Overrides default stack 
diff --git a/lib/CodeGen/BackendUtil.cpp b/lib/CodeGen/BackendUtil.cpp
index 62f87c983b..4fe5d81a4d 100644
--- a/lib/CodeGen/BackendUtil.cpp
+++ b/lib/CodeGen/BackendUtil.cpp
@@ -401,6 +401,7 @@ TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
   Options.UseSoftFloat = CodeGenOpts.SoftFloat;
   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
   Options.RealignStack = CodeGenOpts.StackRealignment;
+  Options.StrictAlign = CodeGenOpts.StrictAlign;
   Options.DisableTailCalls = CodeGenOpts.DisableTailCalls;
   Options.TrapFuncName = CodeGenOpts.TrapFuncName;
   Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 866d70226d..3a6ecd7d3b 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -2533,6 +2533,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     StringRef alignment = Args.getLastArgValue(options::OPT_mstack_alignment);
     CmdArgs.push_back(Args.MakeArgString("-mstack-alignment=" + alignment));
   }
+  if (Args.hasArg(options::OPT_mstrict_align)) {
+    CmdArgs.push_back(Args.MakeArgString("-mstrict-align"));
+  }
 
   // Forward -f options with positive and negative forms; we translate
   // these by hand.
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index d0ff7d2345..5663d8b750 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -407,6 +407,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.SSPBufferSize =
     Args.getLastArgIntValue(OPT_stack_protector_buffer_size, 8, Diags);
   Opts.StackRealignment = Args.hasArg(OPT_mstackrealign);
+  Opts.StrictAlign = Args.hasArg(OPT_mstrict_align);
   if (Arg *A = Args.getLastArg(OPT_mstack_alignment)) {
     StringRef Val = A->getValue();
     unsigned StackAlignment = Opts.StackAlignment;