Initial skeleton of Subzero.

src/IceGlobalContext.cpp

+//===- subzero/src/IceGlobalContext.cpp - Global context defs ---*- C++ -*-===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines aspects of the compilation that persist across
+// multiple functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "IceDefs.h"
+#include "IceTypes.h"
+#include "IceCfg.h"
+#include "IceGlobalContext.h"
+#include "IceOperand.h"
+
+namespace Ice {
+
+// TypePool maps constants of type KeyType (e.g. float) to pointers
+// to type ValueType (e.g. ConstantFloat).  KeyType values are
+// compared using memcmp() because of potential NaN values in KeyType
+// values.  TODO: allow a custom KeyType comparator for a KeyType
+// containing e.g. a non-pooled string.
+template <typename KeyType, typename ValueType> class TypePool {
+  TypePool(const TypePool &) LLVM_DELETED_FUNCTION;
+  TypePool &operator=(const TypePool &) LLVM_DELETED_FUNCTION;
+
+public:
+  TypePool() {}
+  ValueType *getOrAdd(GlobalContext *Ctx, IceType Type, KeyType Key) {
+    IceSize_t Index = KeyToIndex.translate(std::make_pair(Type, Key));
+    if (Index >= Pool.size()) {
+      assert(Index == Pool.size());
+      Pool.resize(Index + 1);
+      Pool[Index] = ValueType::create(Ctx, Type, Key);
+    }
+    ValueType *Constant = Pool[Index];
+    assert(Constant);
+    return Constant;
+  }
+
+private:
+  typedef std::pair<IceType, KeyType> TupleType;
+  struct TupleCompare {
+    bool operator()(const TupleType &A, const TupleType &B) {
+      if (A.first != B.first)

[JF, 2014/04/23 03:51:28]

Ditto on static_assert for !FP.

[Jim Stichnoth, 2014/04/26 15:02:11]

This isn't necessary, since the type of A.first and B.first is always IceType
which is an enum.

+        return A.first < B.first;
+      return memcmp(&A.second, &B.second, sizeof(KeyType)) < 0;
+    }
+  };
+  ValueTranslation<TupleType, TupleCompare> KeyToIndex;
+  std::vector<ValueType *> Pool;
+};
+
+// The global constant pool bundles individual pools of each type of
+// interest.
+class ConstantPool {
+  ConstantPool(const ConstantPool &) LLVM_DELETED_FUNCTION;
+  ConstantPool &operator=(const ConstantPool &) LLVM_DELETED_FUNCTION;
+
+public:
+  ConstantPool() {}
+  TypePool<float, ConstantFloat> Floats;
+  TypePool<double, ConstantDouble> Doubles;
+  TypePool<uint64_t, ConstantInteger> Integers;
+  TypePool<RelocatableTuple, ConstantRelocatable> Relocatables;
+};
+
+GlobalContext::GlobalContext(llvm::raw_ostream *OsDump,
+                             llvm::raw_ostream *OsEmit,
+                             IceVerboseMask VerboseMask, IceString TestPrefix)
+    : StrDump(OsDump), StrEmit(OsEmit), VerboseMask(VerboseMask),
+      ConstPool(new ConstantPool()), TestPrefix(TestPrefix) {}
+
+// In this context, name mangling means to rewrite a symbol using a
+// given prefix.  For a C++ symbol, nest the original symbol inside
+// the "prefix" namespace.  For other symbols, just prepend the
+// prefix.
+IceString GlobalContext::mangleName(const IceString &Name) const {
+  // An already-nested name like foo::bar() gets pushed down one
+  // level, making it equivalent to Prefix::foo::bar().
+  //   _ZN3foo3barExyz ==> _ZN6Prefix3foo3barExyz
+  // A non-nested but mangled name like bar() gets nested, making it
+  // equivalent to Prefix::bar().
+  //   _Z3barxyz ==> ZN6Prefix3barExyz
+  // An unmangled, extern "C" style name, gets a simple prefix:
+  //   bar ==> Prefixbar
+  if (getTestPrefix() == "")
+    return Name;
+
+  unsigned PrefixLength = getTestPrefix().length();
+  char NameBase[1 + Name.length()];
+  const size_t BufLen = 30 + Name.length() + getTestPrefix().length();
+  char NewName[BufLen];
+  uint32_t BaseLength = 0;
+
+  int ItemsParsed = sscanf(Name.c_str(), "_ZN%s", NameBase);
+  if (ItemsParsed == 1) {
+    // Transform _ZN3foo3barExyz ==> _ZN6Prefix3foo3barExyz
+    //   (splice in "6Prefix")          ^^^^^^^
+    snprintf(NewName, BufLen, "_ZN%u%s%s", PrefixLength,
+             getTestPrefix().c_str(), NameBase);
+    // We ignore the snprintf return value (here and below).  If we
+    // somehow miscalculated the output buffer length, the output will
+    // be truncated, but it will be truncated consistently for all
+    // mangleName() calls on the same input string.
+    return NewName;
+  }
+
+  ItemsParsed = sscanf(Name.c_str(), "_Z%u%s", &BaseLength, NameBase);
+  if (ItemsParsed == 2) {
+    // Transform _Z3barxyz ==> ZN6Prefix3barExyz
+    //                          ^^^^^^^^    ^
+    // (splice in "N6Prefix", and insert "E" after "3bar")
+    char OrigName[Name.length()];
+    char OrigSuffix[Name.length()];
+    strncpy(OrigName, NameBase, BaseLength);
+    OrigName[BaseLength] = '\0';
+    strcpy(OrigSuffix, NameBase + BaseLength);
+    snprintf(NewName, BufLen, "_ZN%u%s%u%sE%s", PrefixLength,
+             getTestPrefix().c_str(), BaseLength, OrigName, OrigSuffix);
+    return NewName;
+  }
+
+  // Transform bar ==> Prefixbar
+  //                   ^^^^^^
+  return getTestPrefix() + Name;
+}

[JF, 2014/04/23 03:51:28]

Could you add tests for this function? It gave me a mild headache, but I think
it's correct :)

[Jim Stichnoth, 2014/04/26 15:02:11]

How about a TODO for the next CL?  I probably should have held this method back
for this CL since there aren't any actual callers yet.

+
+GlobalContext::~GlobalContext() {}
+
+Constant *GlobalContext::getConstantInt(IceType Type, uint64_t ConstantInt64) {
+  return ConstPool->Integers.getOrAdd(this, Type, ConstantInt64);
+}
+
+Constant *GlobalContext::getConstantFloat(float ConstantFloat) {
+  return ConstPool->Floats.getOrAdd(this, IceType_f32, ConstantFloat);
+}
+
+Constant *GlobalContext::getConstantDouble(double ConstantDouble) {
+  return ConstPool->Doubles.getOrAdd(this, IceType_f64, ConstantDouble);
+}
+
+Constant *GlobalContext::getConstantSym(IceType Type, int64_t Offset,
+                                        const IceString &Name,
+                                        bool SuppressMangling) {
+  return ConstPool->Relocatables.getOrAdd(
+      this, Type, RelocatableTuple(Offset, Name, SuppressMangling));
+}
+
+void IceTimer::printElapsedUs(GlobalContext *Ctx, const IceString &Tag) const {
+  if (Ctx->isVerbose(IceV_Timing)) {
+    // Prefixing with '#' allows timing strings to be included
+    // without error in textual assembly output.
+    Ctx->getStrDump() << "# " << getElapsedUs() << " usec " << Tag << "\n";
+  }
+}
+
+} // end of namespace Ice