Add an MCSubtargetInfo variable to the TargetMachine.

This enables us to remove calls to the subtarget from the TargetMachine
and with a small hack for backends that require global subtarget
information for module level code generation, e.g. mips abi flags, as
mentioned in a fixme in the code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232776 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetMachine.h

@@ -32,6 +32,7 @@ class MCCodeGenInfo;
 class MCContext;
 class MCInstrInfo;
 class MCRegisterInfo;
+class MCSubtargetInfo;
 class MCSymbol;
 class Target;
 class DataLayout;
@@ -90,6 +91,7 @@ protected: // Can only create subclasses.
   const MCAsmInfo *AsmInfo;
   const MCRegisterInfo *MRI;
   const MCInstrInfo *MII;
+  const MCSubtargetInfo *STI;
 
   unsigned RequireStructuredCFG : 1;
 
@@ -140,6 +142,7 @@ public:
   const MCAsmInfo *getMCAsmInfo() const { return AsmInfo; }
   const MCRegisterInfo *getMCRegisterInfo() const { return MRI; }
   const MCInstrInfo *getMCInstrInfo() const { return MII; }
+  const MCSubtargetInfo *getMCSubtargetInfo() const { return STI; }
 
   /// getIntrinsicInfo - If intrinsic information is available, return it.  If
   /// not, return null.

lib/CodeGen/LLVMTargetMachine.cpp

@@ -49,6 +49,12 @@ EnableFastISelOption("fast-isel", cl::Hidden,
 void LLVMTargetMachine::initAsmInfo() {
   MRI = TheTarget.createMCRegInfo(getTargetTriple());
   MII = TheTarget.createMCInstrInfo();
+  // FIXME: Having an MCSubtargetInfo on the target machine is a hack due
+  // to some backends having subtarget feature dependent module level
+  // code generation. This is similar to the hack in the AsmPrinter for
+  // module level assembly etc.
+  STI = TheTarget.createMCSubtargetInfo(getTargetTriple(), getTargetCPU(),
+                                        getTargetFeatureString());
 
   MCAsmInfo *TmpAsmInfo = TheTarget.createMCAsmInfo(*MRI, getTargetTriple());
   // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
@@ -163,7 +169,7 @@ bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
   if (Options.MCOptions.MCSaveTempLabels)
     Context->setAllowTemporaryLabels(false);
 
-  const MCSubtargetInfo &STI = getSubtarget<MCSubtargetInfo>();
+  const MCSubtargetInfo &STI = *getMCSubtargetInfo();
   const MCAsmInfo &MAI = *getMCAsmInfo();
   const MCRegisterInfo &MRI = *getMCRegisterInfo();
   const MCInstrInfo &MII = *getMCInstrInfo();
@@ -249,7 +255,7 @@ bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM,
     return true;
 
   Triple T(getTargetTriple());
-  const MCSubtargetInfo &STI = getSubtarget<MCSubtargetInfo>();
+  const MCSubtargetInfo &STI = *getMCSubtargetInfo();
   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
       T, *Ctx, *MAB, Out, MCE, STI, Options.MCOptions.MCRelaxAll));
 

lib/Target/TargetMachine.cpp

@@ -42,13 +42,15 @@ TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString,
                              const TargetOptions &Options)
     : TheTarget(T), DL(DataLayoutString), TargetTriple(TT), TargetCPU(CPU),
       TargetFS(FS), CodeGenInfo(nullptr), AsmInfo(nullptr), MRI(nullptr),
-      MII(nullptr), RequireStructuredCFG(false), Options(Options) {}
+      MII(nullptr), STI(nullptr), RequireStructuredCFG(false),
+      Options(Options) {}
 
 TargetMachine::~TargetMachine() {
   delete CodeGenInfo;
   delete AsmInfo;
   delete MRI;
   delete MII;
+  delete STI;
 }
 
 /// \brief Reset the target options based on the function's attributes.