Implements include/exclude register lists for translation.

src/IceTargetLowering.cpp

 //===- subzero/src/IceTargetLowering.cpp - Basic lowering implementation --===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 21 matching lines @@
 // (TargetLowering, TargetDataLowering, and TargetHeaderLowering) we use the
 // following named constructors. For reference, each target Foo needs to
 // implement the following named constructors and initializer:
 //
 // namespace Foo {
 //   unique_ptr<Ice::TargetLowering> createTargetLowering(Ice::Cfg *);
 //   unique_ptr<Ice::TargetDataLowering>
 //       createTargetDataLowering(Ice::GlobalContext*);
 //   unique_ptr<Ice::TargetHeaderLowering>
 //       createTargetHeaderLowering(Ice::GlobalContext *);
-//   void staticInit(const ::Ice::ClFlags &Flags);
+//   void staticInit(::Ice::GlobalContext *);
 // }
 #define SUBZERO_TARGET(X)                                                      \
   namespace X {                                                                \
   std::unique_ptr<::Ice::TargetLowering>                                       \
   createTargetLowering(::Ice::Cfg *Func);                                      \
   std::unique_ptr<::Ice::TargetDataLowering>                                   \
   createTargetDataLowering(::Ice::GlobalContext *Ctx);                         \
   std::unique_ptr<::Ice::TargetHeaderLowering>                                 \
   createTargetHeaderLowering(::Ice::GlobalContext *Ctx);                       \
-  void staticInit(const ::Ice::ClFlags &Flags);                                \
+  void staticInit(::Ice::GlobalContext *Ctx);                                  \
   } // end of namespace X
 #include "llvm/Config/SZTargets.def"
 #undef SUBZERO_TARGET
 
 namespace Ice {
 void LoweringContext::init(CfgNode *N) {
   Node = N;
   End = getNode()->getInsts().end();
   rewind();
   advanceForward(Next);
@@ skipping 46 matching lines @@
   LastSrc = llvm::cast<Variable>(Instr->getSrc(0));
 }
 
 Variable *LoweringContext::availabilityGet(Operand *Src) const {
   assert(Src);
   if (Src == LastDest)
     return LastSrc;
   return nullptr;
 }
 
+namespace {
+
+void printRegisterSet(Ostream &Str, const llvm::SmallBitVector &Bitset,
+                      std::function<IceString(int32_t)> getRegName,

[Jim Stichnoth, 2016/01/15 00:50:56]

My head nearly exploded as I investigated the inconsistency between int32_t and
SizeT in the various getRegName() methods. :(

My conclusion: just keep it int32_t here.

[Karl, 2016/01/15 16:54:24]

Acknowledged.

+                      SizeT LineIndent) {

[Jim Stichnoth, 2016/01/15 00:50:56]

Change SizeT to size_t.

Also, I would change its name to something like LineIndentSpaces to distinguish
it from the differently-typed LineIndent var in the caller.  (Or change the
caller's var name to something like LineIndentString.)

[Karl, 2016/01/15 16:54:24]

Done.

+  constexpr int RegistersPerLine = 16;

[Jim Stichnoth, 2016/01/15 00:50:56]

Probably want the types of RegisterPerLine and Count to match.

[Karl, 2016/01/15 16:54:24]

Done.

+  size_t Count = 0;
+  constexpr int BitsetEnd = -1;

[Jim Stichnoth, 2016/01/15 00:50:56]

I wouldn't use BitsetEnd, I would just use the raw -1, magic constant
notwithstanding.  All the other code uses -1 (or >= 0 in IceRegAlloc.cpp for
some reason), and the external API explicitly says -1.

[Karl, 2016/01/15 16:54:24]

Done.

+  IceString Indent = std::string(LineIndent, ' ');
+  for (int i = Bitset.find_first(); i != BitsetEnd; i = Bitset.find_next(i)) {
+    if (Count == 0) {
+      Str << Indent;
+    } else {
+      Str << ",";
+    }
+    if (Count > 0 && Count % RegistersPerLine == 0)
+      Str << "\n" << Indent;
+    ++Count;
+    Str << getRegName(i);
+  }
+  if (Count)
+    Str << "\n";
+}
+
+} // end of anonymous namespace
+
+void TargetLowering::filterTypeToRegisterSet(
+    GlobalContext *Ctx, int32_t NumRegs,
+    llvm::SmallBitVector TypeToRegisterSet[], size_t TypeToRegisterSetSize,
+    std::function<IceString(int32_t)> getRegName) {
+  llvm::SmallBitVector ExcludeBitSet(NumRegs);
+  std::vector<llvm::SmallBitVector> UseSet(TypeToRegisterSetSize,
+                                           ExcludeBitSet);
+  ExcludeBitSet.flip();
+
+  std::unordered_map<IceString, int32_t> RegNameToIndex;
+  for (int32_t RegIndex = 0; RegIndex < NumRegs; ++RegIndex)
+    RegNameToIndex[getRegName(RegIndex)] = RegIndex;
+
+  for (const IceString &RegName : Ctx->getFlags().getUseRestrictedRegisters()) {
+    if (!RegNameToIndex.count(RegName))
+      llvm::report_fatal_error("Can't find register use: " + RegName);

[Jim Stichnoth, 2016/01/15 00:50:56]

It would be nicer if it would tell me *all* the registers I botched, not just
the first one.  One possibility is to initialize an IceString to the empty
string, then append " "+RegName for each offending register, then at the very
end check for a nonempty string.

[Karl, 2016/01/15 16:54:24]

Done.

+    const int32_t RegIndex = RegNameToIndex[RegName];
+    for (SizeT TypeIndex = 0; TypeIndex < TypeToRegisterSetSize; ++TypeIndex)
+      UseSet[TypeIndex][RegIndex] = TypeToRegisterSet[TypeIndex][RegIndex];
+  }
+
+  for (const IceString &RegName : Ctx->getFlags().getExcludedRegisters()) {
+    if (!RegNameToIndex.count(RegName))
+      llvm::report_fatal_error("Can't find register exclude: " + RegName);
+    ExcludeBitSet[RegNameToIndex[RegName]] = false;
+  }
+
+  // Apply filters.
+  for (size_t TypeIndex = 0; TypeIndex < TypeToRegisterSetSize; ++TypeIndex) {
+    llvm::SmallBitVector *TypeBitSet = &TypeToRegisterSet[TypeIndex];
+    llvm::SmallBitVector *UseBitSet = &UseSet[TypeIndex];
+    if (UseBitSet->any())
+      *TypeBitSet = *UseBitSet;
+    *TypeBitSet &= ExcludeBitSet;
+  }
+
+  // Display filtered register sets, if requested.
+  if (BuildDefs::dump() && NumRegs &&
+      (Ctx->getFlags().getVerbose() & IceV_AvailableRegs)) {
+    Ostream &Str = Ctx->getStrDump();
+    constexpr const char LineIndent[] = "  ";
+    const size_t RegSetIndent = 2 * llvm::array_lengthof(LineIndent);
+    Str << "Registers available for register allocation:\n";
+    for (size_t TypeIndex = 0; TypeIndex < TypeToRegisterSetSize; ++TypeIndex) {
+      Str << LineIndent;
+      if (TypeIndex < IceType_NUM) {
+        Str << typeString(static_cast<Type>(TypeIndex));
+      } else {
+        Str << "other[" << TypeIndex << "]";
+      }
+      Str << ":\n";
+      printRegisterSet(Str, TypeToRegisterSet[TypeIndex], getRegName,
+                       RegSetIndent);
+    }
+    Str << "\n";
+  }
+}
+
 std::unique_ptr<TargetLowering>
 TargetLowering::createLowering(TargetArch Target, Cfg *Func) {
   switch (Target) {
   default:
     llvm::report_fatal_error("Unsupported target");
 #define SUBZERO_TARGET(X)                                                      \
   case Target_##X:                                                             \
     return ::X::createTargetLowering(Func);
 #include "llvm/Config/SZTargets.def"
 #undef SUBZERO_TARGET
   }
 }
 
-void TargetLowering::staticInit(const ClFlags &Flags) {
-  const TargetArch Target = Flags.getTargetArch();
+void TargetLowering::staticInit(GlobalContext *Ctx) {
+  const TargetArch Target = Ctx->getFlags().getTargetArch();
   // Call the specified target's static initializer.
   switch (Target) {
   default:
     llvm::report_fatal_error("Unsupported target");
 #define SUBZERO_TARGET(X)                                                      \
   case Target_##X: {                                                           \
     static bool InitGuard##X = false;                                          \
     if (InitGuard##X) {                                                        \
       return;                                                                  \
     }                                                                          \
     InitGuard##X = true;                                                       \
-    ::X::staticInit(Flags);                                                    \
+    ::X::staticInit(Ctx);                                                      \
   } break;
 #include "llvm/Config/SZTargets.def"
 #undef SUBZERO_TARGET
   }
 }
 
 TargetLowering::TargetLowering(Cfg *Func)
     : Func(Func), Ctx(Func->getContext()), Context() {}
 
 void TargetLowering::genTargetHelperCalls() {
@@ skipping 526 matching lines @@
   case Target_##X:                                                             \
     return ::X::createTargetHeaderLowering(Ctx);
 #include "llvm/Config/SZTargets.def"
 #undef SUBZERO_TARGET
   }
 }
 
 TargetHeaderLowering::~TargetHeaderLowering() = default;
 
 } // end of namespace Ice