This patch enables llvm to switch between compiling for mips32/mips64

and mips16 on a per function basis.

Because this patch is somewhat involved I have provide an overview of the
key pieces of it.

The patch is written so as to not change the behavior of the non mixed
mode. We have tested this a lot but it is something new to switch subtargets
so we don't want any chance of regression in the mainline compiler until
we have more confidence in this.

Mips32/64 are very different from Mip16 as is the case of ARM vs Thumb1.
For that reason there are derived versions of the register info, frame info, 
instruction info and instruction selection classes.

Now we register three separate passes for instruction selection.
One which is used to switch subtargets (MipsModuleISelDAGToDAG.cpp) and then
one for each of the current subtargets (Mips16ISelDAGToDAG.cpp and
MipsSEISelDAGToDAG.cpp).

When the ModuleISel pass runs, it determines if there is a need to switch
subtargets and if so, the owning pointers in MipsTargetMachine are
appropriately changed.

When 16Isel or SEIsel is run, they will return immediately without doing
any work if the current subtarget mode does not apply to them.

In addition, MipsAsmPrinter needs to be reset on a function basis.

The pass BasicTargetTransformInfo is substituted with a null pass since the
pass is immutable and really needs to be a function pass for it to be
used with changing subtargets. This will be fixed in a follow on patch.

llvm-svn: 179118

1 files changed, 78 insertions, 6 deletions

diff --git a/llvm/lib/Target/Mips/MipsTargetMachine.cpp b/llvm/lib/Target/Mips/MipsTargetMachine.cpp
index 3336358..18c1cce 100644
--- a/llvm/lib/Target/Mips/MipsTargetMachine.cpp
+++ b/llvm/lib/Target/Mips/MipsTargetMachine.cpp
@@ -15,11 +15,25 @@
 #include "Mips.h"
 #include "MipsFrameLowering.h"
 #include "MipsInstrInfo.h"
+#include "MipsModuleISelDAGToDAG.h"
+#include "MipsSEFrameLowering.h"
+#include "MipsSEInstrInfo.h"
+#include "MipsSEISelLowering.h"
+#include "MipsSEISelDAGToDAG.h"
+#include "Mips16FrameLowering.h"
+#include "Mips16InstrInfo.h"
+#include "Mips16ISelDAGToDAG.h"
+#include "Mips16ISelLowering.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/PassManager.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/TargetRegistry.h"
 using namespace llvm;
 
+
+
 extern "C" void LLVMInitializeMipsTarget() {
   // Register the target.
   RegisterTargetMachine<MipsebTargetMachine> X(TheMipsTarget);
@@ -42,7 +56,7 @@ MipsTargetMachine(const Target &T, StringRef TT,
                   CodeGenOpt::Level OL,
                   bool isLittle)
   : LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
-    Subtarget(TT, CPU, FS, isLittle, RM),
+    Subtarget(TT, CPU, FS, isLittle, RM, this),
     DL(isLittle ?
                (Subtarget.isABI_N64() ?
                 "e-p:64:64:64-i8:8:32-i16:16:32-i64:64:64-f128:128:128-"
@@ -54,9 +68,46 @@ MipsTargetMachine(const Target &T, StringRef TT,
                 "E-p:32:32:32-i8:8:32-i16:16:32-i64:64:64-n32-S64")),
     InstrInfo(MipsInstrInfo::create(*this)),
     FrameLowering(MipsFrameLowering::create(*this, Subtarget)),
-    TLInfo(MipsTargetLowering::create(*this)), TSInfo(*this), JITInfo() {
+    TLInfo(MipsTargetLowering::create(*this)),
+    TSInfo(*this), JITInfo() {
+}
+
+
+void MipsTargetMachine::setHelperClassesMips16() {
+  InstrInfoSE.swap(InstrInfo);
+  FrameLoweringSE.swap(FrameLowering);
+  TLInfoSE.swap(TLInfo);
+  if (!InstrInfo16) {
+    InstrInfo.reset(MipsInstrInfo::create(*this));
+    FrameLowering.reset(MipsFrameLowering::create(*this, Subtarget));
+    TLInfo.reset(MipsTargetLowering::create(*this));
+  } else {
+    InstrInfo16.swap(InstrInfo);
+    FrameLowering16.swap(FrameLowering);
+    TLInfo16.swap(TLInfo);
+  }
+  assert(TLInfo && "null target lowering 16");
+  assert(InstrInfo && "null instr info 16");
+  assert(FrameLowering && "null frame lowering 16");
 }
 
+void MipsTargetMachine::setHelperClassesMipsSE() {
+  InstrInfo16.swap(InstrInfo);
+  FrameLowering16.swap(FrameLowering);
+  TLInfo16.swap(TLInfo);
+  if (!InstrInfoSE) {
+    InstrInfo.reset(MipsInstrInfo::create(*this));
+    FrameLowering.reset(MipsFrameLowering::create(*this, Subtarget));
+    TLInfo.reset(MipsTargetLowering::create(*this));
+  } else {
+    InstrInfoSE.swap(InstrInfo);
+    FrameLoweringSE.swap(FrameLowering);
+    TLInfoSE.swap(TLInfo);
+  }
+  assert(TLInfo && "null target lowering in SE");
+  assert(InstrInfo && "null instr info SE");
+  assert(FrameLowering && "null frame lowering SE");
+}
 void MipsebTargetMachine::anchor() { }
 
 MipsebTargetMachine::
@@ -102,21 +153,42 @@ TargetPassConfig *MipsTargetMachine::createPassConfig(PassManagerBase &PM) {
 // Install an instruction selector pass using
 // the ISelDag to gen Mips code.
 bool MipsPassConfig::addInstSelector() {
-  addPass(createMipsISelDag(getMipsTargetMachine()));
+  if (getMipsSubtarget().allowMixed16_32()) {
+    addPass(createMipsModuleISelDag(getMipsTargetMachine()));
+    addPass(createMips16ISelDag(getMipsTargetMachine()));
+    addPass(createMipsSEISelDag(getMipsTargetMachine()));
+  } else {
+    addPass(createMipsISelDag(getMipsTargetMachine()));
+  }
   return false;
 }
 
+void MipsTargetMachine::addAnalysisPasses(PassManagerBase &PM) {
+  if (Subtarget.allowMixed16_32()) {
+    DEBUG(errs() << "No ");
+    //FIXME: The Basic Target Transform Info
+    // pass needs to become a function pass instead of
+    // being an immutable pass and then this method as it exists now
+    // would be unnecessary.
+    PM.add(createNoTargetTransformInfoPass());
+  } else
+    LLVMTargetMachine::addAnalysisPasses(PM);
+  DEBUG(errs() << "Target Transform Info Pass Added\n");
+}
+
 // Implemented by targets that want to run passes immediately before
 // machine code is emitted. return true if -print-machineinstrs should
 // print out the code after the passes.
 bool MipsPassConfig::addPreEmitPass() {
   MipsTargetMachine &TM = getMipsTargetMachine();
+  const MipsSubtarget &Subtarget = TM.getSubtarget<MipsSubtarget>();
   addPass(createMipsDelaySlotFillerPass(TM));
 
-  // NOTE: long branch has not been implemented for mips16.
-  if (TM.getSubtarget<MipsSubtarget>().hasStandardEncoding())
+  if (Subtarget.hasStandardEncoding() ||
+      Subtarget.allowMixed16_32())
     addPass(createMipsLongBranchPass(TM));
-  if (TM.getSubtarget<MipsSubtarget>().inMips16Mode())
+  if (Subtarget.inMips16Mode() ||
+      Subtarget.allowMixed16_32())
     addPass(createMipsConstantIslandPass(TM));
 
   return true;