Initial skeleton of Subzero.

src/IceGlobalContext.cpp

Index: src/IceGlobalContext.cpp
diff --git a/src/IceGlobalContext.cpp b/src/IceGlobalContext.cpp
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+//===- 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.
+// KeyTypeHasFP indicates whether KeyType is a floating-point type
+// whose values need to be compared using memcmp() for NaN
+// correctness.  TODO: use std::is_floating_point<KeyType> instead of
+// KeyTypeHasFP with C++11.
+template <typename KeyType, typename ValueType, bool KeyTypeHasFP = false>
+class TypePool {
+  TypePool(const TypePool &) LLVM_DELETED_FUNCTION;
+  TypePool &operator=(const TypePool &) LLVM_DELETED_FUNCTION;
+
+public:
+  TypePool() {}
+  ValueType *getOrAdd(GlobalContext *Ctx, Type Ty, KeyType Key) {
+    TupleType TupleKey = std::make_pair(Ty, Key);
+    typename ContainerType::const_iterator Iter = Pool.find(TupleKey);
+    if (Iter != Pool.end())
+      return Iter->second;
+    ValueType *Result = ValueType::create(Ctx, Ty, Key);
+    Pool[TupleKey] = Result;
+    return Result;
+  }
+
+private:
+  typedef std::pair<Type, KeyType> TupleType;
+  struct TupleCompare {
+    bool operator()(const TupleType &A, const TupleType &B) {
+      if (A.first != B.first)
+        return A.first < B.first;
+      if (KeyTypeHasFP)
+        return memcmp(&A.second, &B.second, sizeof(KeyType)) < 0;
+      return A.second < B.second;
+    }
+  };
+  typedef std::map<const TupleType, ValueType *, TupleCompare> ContainerType;
+  ContainerType 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, true> Floats;
+  TypePool<double, ConstantDouble, true> Doubles;
+  TypePool<uint64_t, ConstantInteger> Integers;
+  TypePool<RelocatableTuple, ConstantRelocatable> Relocatables;
+};
+
+GlobalContext::GlobalContext(llvm::raw_ostream *OsDump,
+                             llvm::raw_ostream *OsEmit, VerboseMask Mask,
+                             IceString TestPrefix)
+    : StrDump(OsDump), StrEmit(OsEmit), VMask(Mask),
+      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 {
+  // TODO: Add explicit tests (beyond the implicit tests in the linker
+  // that come from the cross tests).
+  //
+  // 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().empty())
+    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;
+}
+
+GlobalContext::~GlobalContext() {}
+
+Constant *GlobalContext::getConstantInt(Type Ty, uint64_t ConstantInt64) {
+  return ConstPool->Integers.getOrAdd(this, Ty, 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(Type Ty, int64_t Offset,
+                                        const IceString &Name,
+                                        bool SuppressMangling) {
+  return ConstPool->Relocatables.getOrAdd(
+      this, Ty, RelocatableTuple(Offset, Name, SuppressMangling));
+}
+
+void Timer::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