Reset some of the target options which affect code generation.

This doesn't reset all of the target options within the TargetOptions
object. This is because some of those are ABI-specific and must be determined if
it's okay to change those on the fly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176986 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 0 deletions

diff --git a/lib/Target/TargetMachine.cpp b/lib/Target/TargetMachine.cpp
index 7d8b49cdf2..e7282519d5 100644
--- a/lib/Target/TargetMachine.cpp
+++ b/lib/Target/TargetMachine.cpp
@@ -12,6 +12,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/GlobalVariable.h"
@@ -61,6 +63,30 @@ TargetMachine::~TargetMachine() {
   delete AsmInfo;
 }
 
+/// \brief Reset the target options based on the function's attributes.
+void TargetMachine::resetTargetOptions(const MachineFunction *MF) const {
+  const Function *F = MF->getFunction();
+  TargetOptions &TO = MF->getTarget().Options;
+  
+#define RESET_OPTION(X, Y)                                              \
+  do {                                                                  \
+    if (F->hasFnAttribute(Y))                                           \
+      TO.X =                                                            \
+        (F->getAttributes().                                            \
+           getAttribute(AttributeSet::FunctionIndex,                    \
+                        Y).getValueAsString() == "true");               \
+  } while (0)
+
+  RESET_OPTION(NoFramePointerElim, "no-frame-pointer-elim");
+  RESET_OPTION(NoFramePointerElimNonLeaf, "no-frame-pointer-elim-non-leaf");
+  RESET_OPTION(LessPreciseFPMADOption, "less-precise-fpmad");
+  RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
+  RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
+  RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
+  RESET_OPTION(UseSoftFloat, "use-soft-float");
+  RESET_OPTION(DisableTailCalls, "disable-tail-calls");
+}
+
 /// getRelocationModel - Returns the code generation relocation model. The
 /// choices are static, PIC, and dynamic-no-pic, and target default.
 Reloc::Model TargetMachine::getRelocationModel() const {