PPC: Refactoring to support subtarget feature changing

This change mirrors the changes that were made to the X86 and ARM targets to
support subtarget feature changing. As indicated in r182899, the mechanism is
still undergoing revision, and so as with the X86 and ARM targets, there is no
test case yet (there is no effective functionality change).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186357 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 69 insertions, 37 deletions

diff --git a/lib/Target/PowerPC/PPCSubtarget.cpp b/lib/Target/PowerPC/PPCSubtarget.cpp
index a8f2b3f..51fbfda 100644
--- a/lib/Target/PowerPC/PPCSubtarget.cpp
+++ b/lib/Target/PowerPC/PPCSubtarget.cpp
@@ -14,7 +14,10 @@
 #include "PPCSubtarget.h"
 #include "PPC.h"
 #include "PPCRegisterInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/IR/Attributes.h"
 #include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/Function.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Target/TargetMachine.h"
@@ -29,32 +32,67 @@ using namespace llvm;
 PPCSubtarget::PPCSubtarget(const std::string &TT, const std::string &CPU,
                            const std::string &FS, bool is64Bit)
   : PPCGenSubtargetInfo(TT, CPU, FS)
-  , StackAlignment(16)
-  , DarwinDirective(PPC::DIR_NONE)
-  , HasMFOCRF(false)
-  , Has64BitSupport(false)
-  , Use64BitRegs(false)
   , IsPPC64(is64Bit)
-  , HasAltivec(false)
-  , HasQPX(false)
-  , HasFSQRT(false)
-  , HasFRE(false)
-  , HasFRES(false)
-  , HasFRSQRTE(false)
-  , HasFRSQRTES(false)
-  , HasRecipPrec(false)
-  , HasSTFIWX(false)
-  , HasLFIWAX(false)
-  , HasFPRND(false)
-  , HasFPCVT(false)
-  , HasISEL(false)
-  , HasPOPCNTD(false)
-  , HasLDBRX(false)
-  , IsBookE(false)
-  , HasLazyResolverStubs(false)
-  , IsJITCodeModel(false)
   , TargetTriple(TT) {
+  initializeEnvironment();
+  resetSubtargetFeatures(CPU, FS);
+}
+
+/// SetJITMode - This is called to inform the subtarget info that we are
+/// producing code for the JIT.
+void PPCSubtarget::SetJITMode() {
+  // JIT mode doesn't want lazy resolver stubs, it knows exactly where
+  // everything is.  This matters for PPC64, which codegens in PIC mode without
+  // stubs.
+  HasLazyResolverStubs = false;
+
+  // Calls to external functions need to use indirect calls
+  IsJITCodeModel = true;
+}
+
+void PPCSubtarget::resetSubtargetFeatures(const MachineFunction *MF) {
+  AttributeSet FnAttrs = MF->getFunction()->getAttributes();
+  Attribute CPUAttr = FnAttrs.getAttribute(AttributeSet::FunctionIndex,
+                                           "target-cpu");
+  Attribute FSAttr = FnAttrs.getAttribute(AttributeSet::FunctionIndex,
+                                          "target-features");
+  std::string CPU =
+    !CPUAttr.hasAttribute(Attribute::None) ? CPUAttr.getValueAsString() : "";
+  std::string FS =
+    !FSAttr.hasAttribute(Attribute::None) ? FSAttr.getValueAsString() : "";
+  if (!FS.empty()) {
+    initializeEnvironment();
+    resetSubtargetFeatures(CPU, FS);
+  }
+}
 
+void PPCSubtarget::initializeEnvironment() {
+  StackAlignment = 16;
+  DarwinDirective = PPC::DIR_NONE;
+  HasMFOCRF = false;
+  Has64BitSupport = false;
+  Use64BitRegs = false;
+  HasAltivec = false;
+  HasQPX = false;
+  HasFSQRT = false;
+  HasFRE = false;
+  HasFRES = false;
+  HasFRSQRTE = false;
+  HasFRSQRTES = false;
+  HasRecipPrec = false;
+  HasSTFIWX = false;
+  HasLFIWAX = false;
+  HasFPRND = false;
+  HasFPCVT = false;
+  HasISEL = false;
+  HasPOPCNTD = false;
+  HasLDBRX = false;
+  IsBookE = false;
+  HasLazyResolverStubs = false;
+  IsJITCodeModel = false;
+}
+
+void PPCSubtarget::resetSubtargetFeatures(StringRef CPU, StringRef FS) {
   // Determine default and user specified characteristics
   std::string CPUName = CPU;
   if (CPUName.empty())
@@ -72,7 +110,7 @@ PPCSubtarget::PPCSubtarget(const std::string &TT, const std::string &CPU,
   std::string FullFS = FS;
 
   // If we are generating code for ppc64, verify that options make sense.
-  if (is64Bit) {
+  if (IsPPC64) {
     Has64BitSupport = true;
     // Silently force 64-bit register use on ppc64.
     Use64BitRegs = true;
@@ -101,19 +139,6 @@ PPCSubtarget::PPCSubtarget(const std::string &TT, const std::string &CPU,
     StackAlignment = 32;
 }
 
-/// SetJITMode - This is called to inform the subtarget info that we are
-/// producing code for the JIT.
-void PPCSubtarget::SetJITMode() {
-  // JIT mode doesn't want lazy resolver stubs, it knows exactly where
-  // everything is.  This matters for PPC64, which codegens in PIC mode without
-  // stubs.
-  HasLazyResolverStubs = false;
-
-  // Calls to external functions need to use indirect calls
-  IsJITCodeModel = true;
-}
-
-
 /// hasLazyResolverStub - Return true if accesses to the specified global have
 /// to go through a dyld lazy resolution stub.  This means that an extra load
 /// is required to get the address of the global.
diff --git a/lib/Target/PowerPC/PPCSubtarget.h b/lib/Target/PowerPC/PPCSubtarget.h
index 097f2bc..50af75d 100644
--- a/lib/Target/PowerPC/PPCSubtarget.h
+++ b/lib/Target/PowerPC/PPCSubtarget.h
@@ -137,6 +137,13 @@ public:
                      : "E-p:32:32-f64:64:64-i64:64:64-f128:64:128-n32";
   }
 
+  /// \brief Reset the features for the PowerPC target.
+  virtual void resetSubtargetFeatures(const MachineFunction *MF);
+private:
+  void initializeEnvironment();
+  void resetSubtargetFeatures(StringRef CPU, StringRef FS);
+
+public:
   /// isPPC64 - Return true if we are generating code for 64-bit pointer mode.
   ///
   bool isPPC64() const { return IsPPC64; }