Format: Modernize using variadic templates.

Introduces a subset of C++14 integer sequences in STLExtras. This is
just enough to support unpacking a std::tuple into the arguments of
snprintf, we can add more of it when it's actually needed.

Also removes an ancient macro hack that leaks a macro into the global
namespace. Clean up users that made use of the convenient hack.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229337 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/STLExtras.h

@@ -194,6 +194,28 @@ struct less_second {
   }
 };
 
+// A subset of N3658. More stuff can be added as-needed.
+
+/// \brief Represents a compile-time sequence of integers.
+template <class T, T... I> struct integer_sequence {
+  typedef T value_type;
+
+  static LLVM_CONSTEXPR size_t size() { return sizeof...(I); }
+};
+
+template <std::size_t N, std::size_t... I>
+struct build_index_impl : build_index_impl<N - 1, N - 1, I...> {};
+template <std::size_t... I>
+struct build_index_impl<0, I...> : integer_sequence<std::size_t, I...> {};
+
+/// \brief Alias for the common case of a sequence of size_ts.
+template <size_t... I>
+using index_sequence = integer_sequence<std::size_t, I...>;
+
+/// \brief Creates a compile-time integer sequence for a parameter pack.
+template <class... Ts>
+using index_sequence_for = build_index_impl<sizeof...(Ts)>;
+
 //===----------------------------------------------------------------------===//
 //     Extra additions for arrays
 //===----------------------------------------------------------------------===//

include/llvm/MC/MCInstPrinter.h

@@ -95,14 +95,14 @@ public:
   void setPrintImmHex(HexStyle::Style Value) { PrintHexStyle = Value; }
 
   /// Utility function to print immediates in decimal or hex.
-  format_object1<int64_t> formatImm(const int64_t Value) const {
+  format_object<int64_t> formatImm(int64_t Value) const {
     return PrintImmHex ? formatHex(Value) : formatDec(Value);
   }
 
   /// Utility functions to print decimal/hexadecimal values.
-  format_object1<int64_t> formatDec(const int64_t Value) const;
-  format_object1<int64_t> formatHex(const int64_t Value) const;
-  format_object1<uint64_t> formatHex(const uint64_t Value) const;
+  format_object<int64_t> formatDec(int64_t Value) const;
+  format_object<int64_t> formatHex(int64_t Value) const;
+  format_object<uint64_t> formatHex(uint64_t Value) const;
 };
 
 } // namespace llvm

include/llvm/Support/Format.h

@@ -23,18 +23,12 @@
 #ifndef LLVM_SUPPORT_FORMAT_H
 #define LLVM_SUPPORT_FORMAT_H
 
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/DataTypes.h"
 #include <cassert>
 #include <cstdio>
-#ifdef _MSC_VER
-// FIXME: This define is wrong:
-//  - _snprintf does not guarantee that trailing null is always added - if
-//    there is no space for null, it does not report any error.
-//  - According to C++ standard, snprintf should be visible in the 'std' 
-//    namespace - this define makes this impossible.
-#define snprintf _snprintf
-#endif
+#include <tuple>
 
 namespace llvm {
 
@@ -80,101 +74,26 @@ public:
 /// printed, this synthesizes the string into a temporary buffer provided and
 /// returns whether or not it is big enough.
 
-template <typename T>
-class format_object1 final : public format_object_base {
-  T Val;
-public:
-  format_object1(const char *fmt, const T &val)
-    : format_object_base(fmt), Val(val) {
+template <typename... Ts>
+class format_object final : public format_object_base {
+  std::tuple<Ts...> Vals;
+
+  template <std::size_t... Is>
+  int snprint_tuple(char *Buffer, unsigned BufferSize,
+                    index_sequence<Is...>) const {
+#ifdef _MSC_VER
+    return _snprintf(Buffer, BufferSize, Fmt, std::get<Is>(Vals)...);
+#else
+    return std::snprintf(Buffer, BufferSize, Fmt, std::get<Is>(Vals)...);
+#endif
   }
 
+public:
+  format_object(const char *fmt, const Ts &... vals)
+      : format_object_base(fmt), Vals(vals...) {}
+
   int snprint(char *Buffer, unsigned BufferSize) const override {
-    return snprintf(Buffer, BufferSize, Fmt, Val);
-  }
-};
-
-template <typename T1, typename T2>
-class format_object2 final : public format_object_base {
-  T1 Val1;
-  T2 Val2;
-public:
-  format_object2(const char *fmt, const T1 &val1, const T2 &val2)
-  : format_object_base(fmt), Val1(val1), Val2(val2) {
-  }
-
-  int snprint(char *Buffer, unsigned BufferSize) const override {
-    return snprintf(Buffer, BufferSize, Fmt, Val1, Val2);
-  }
-};
-
-template <typename T1, typename T2, typename T3>
-class format_object3 final : public format_object_base {
-  T1 Val1;
-  T2 Val2;
-  T3 Val3;
-public:
-  format_object3(const char *fmt, const T1 &val1, const T2 &val2,const T3 &val3)
-    : format_object_base(fmt), Val1(val1), Val2(val2), Val3(val3) {
-  }
-
-  int snprint(char *Buffer, unsigned BufferSize) const override {
-    return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3);
-  }
-};
-
-template <typename T1, typename T2, typename T3, typename T4>
-class format_object4 final : public format_object_base {
-  T1 Val1;
-  T2 Val2;
-  T3 Val3;
-  T4 Val4;
-public:
-  format_object4(const char *fmt, const T1 &val1, const T2 &val2,
-                 const T3 &val3, const T4 &val4)
-    : format_object_base(fmt), Val1(val1), Val2(val2), Val3(val3), Val4(val4) {
-  }
-
-  int snprint(char *Buffer, unsigned BufferSize) const override {
-    return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3, Val4);
-  }
-};
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5>
-class format_object5 final : public format_object_base {
-  T1 Val1;
-  T2 Val2;
-  T3 Val3;
-  T4 Val4;
-  T5 Val5;
-public:
-  format_object5(const char *fmt, const T1 &val1, const T2 &val2,
-                 const T3 &val3, const T4 &val4, const T5 &val5)
-    : format_object_base(fmt), Val1(val1), Val2(val2), Val3(val3), Val4(val4),
-      Val5(val5) {
-  }
-
-  int snprint(char *Buffer, unsigned BufferSize) const override {
-    return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3, Val4, Val5);
-  }
-};
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5,
-          typename T6>
-class format_object6 final : public format_object_base {
-  T1 Val1;
-  T2 Val2;
-  T3 Val3;
-  T4 Val4;
-  T5 Val5;
-  T6 Val6;
-public:
-  format_object6(const char *Fmt, const T1 &Val1, const T2 &Val2,
-                 const T3 &Val3, const T4 &Val4, const T5 &Val5, const T6 &Val6)
-    : format_object_base(Fmt), Val1(Val1), Val2(Val2), Val3(Val3), Val4(Val4),
-      Val5(Val5), Val6(Val6) { }
-
-  int snprint(char *Buffer, unsigned BufferSize) const override {
-    return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3, Val4, Val5, Val6);
+    return snprint_tuple(Buffer, BufferSize, index_sequence_for<Ts...>());
   }
 };
 
@@ -187,44 +106,9 @@ public:
 ///   OS << format("%0.4f", myfloat) << '\n';
 /// \endcode
 
-template <typename T>
-inline format_object1<T> format(const char *Fmt, const T &Val) {
-  return format_object1<T>(Fmt, Val);
-}
-
-template <typename T1, typename T2>
-inline format_object2<T1, T2> format(const char *Fmt, const T1 &Val1,
-                                     const T2 &Val2) {
-  return format_object2<T1, T2>(Fmt, Val1, Val2);
-}
-
-template <typename T1, typename T2, typename T3>
-  inline format_object3<T1, T2, T3> format(const char *Fmt, const T1 &Val1,
-                                           const T2 &Val2, const T3 &Val3) {
-  return format_object3<T1, T2, T3>(Fmt, Val1, Val2, Val3);
-}
-
-template <typename T1, typename T2, typename T3, typename T4>
-inline format_object4<T1, T2, T3, T4> format(const char *Fmt, const T1 &Val1,
-                                             const T2 &Val2, const T3 &Val3,
-                                             const T4 &Val4) {
-  return format_object4<T1, T2, T3, T4>(Fmt, Val1, Val2, Val3, Val4);
-}
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5>
-inline format_object5<T1, T2, T3, T4, T5> format(const char *Fmt,const T1 &Val1,
-                                             const T2 &Val2, const T3 &Val3,
-                                             const T4 &Val4, const T5 &Val5) {
-  return format_object5<T1, T2, T3, T4, T5>(Fmt, Val1, Val2, Val3, Val4, Val5);
-}
-
-template <typename T1, typename T2, typename T3, typename T4, typename T5,
-          typename T6>
-inline format_object6<T1, T2, T3, T4, T5, T6>
-format(const char *Fmt, const T1 &Val1, const T2 &Val2, const T3 &Val3,
-       const T4 &Val4, const T5 &Val5, const T6 &Val6) {
-  return format_object6<T1, T2, T3, T4, T5, T6>(Fmt, Val1, Val2, Val3, Val4,
-                                                Val5, Val6);
+template <typename... Ts>
+inline format_object<Ts...> format(const char *Fmt, const Ts &... Vals) {
+  return format_object<Ts...>(Fmt, Vals...);
 }
 
 /// This is a helper class used for left_justify() and right_justify().

lib/MC/MCInstPrinter.cpp

@@ -69,11 +69,11 @@ static bool needsLeadingZero(uint64_t Value)
   return false;
 }
 
-format_object1<int64_t> MCInstPrinter::formatDec(const int64_t Value) const {
+format_object<int64_t> MCInstPrinter::formatDec(int64_t Value) const {
   return format("%" PRId64, Value);
 }
 
-format_object1<int64_t> MCInstPrinter::formatHex(const int64_t Value) const {
+format_object<int64_t> MCInstPrinter::formatHex(int64_t Value) const {
   switch(PrintHexStyle) {
   case HexStyle::C:
     if (Value < 0)
@@ -96,7 +96,7 @@ format_object1<int64_t> MCInstPrinter::formatHex(const int64_t Value) const {
   llvm_unreachable("unsupported print style");
 }
 
-format_object1<uint64_t> MCInstPrinter::formatHex(const uint64_t Value) const {
+format_object<uint64_t> MCInstPrinter::formatHex(uint64_t Value) const {
   switch(PrintHexStyle) {
   case HexStyle::C:
      return format("0x%" PRIx64, Value);

lib/Support/raw_ostream.cpp

@@ -242,7 +242,7 @@ raw_ostream &raw_ostream::operator<<(double N) {
 
   char buf[16];
   unsigned len;
-  len = snprintf(buf, sizeof(buf), "%e", N);
+  len = format("%e", N).snprint(buf, sizeof(buf));
   if (len <= sizeof(buf) - 2) {
     if (len >= 5 && buf[len - 5] == 'e' && buf[len - 3] == '0') {
       int cs = buf[len - 4];

unittests/IR/UseTest.cpp

@@ -50,7 +50,7 @@ TEST(UseTest, sort) {
   });
   unsigned I = 0;
   for (User *U : X.users()) {
-    snprintf(vnbuf, sizeof(vnbuf), "v%u", I++);
+    format("v%u", I++).snprint(vnbuf, sizeof(vnbuf));
     EXPECT_EQ(vnbuf, U->getName());
   }
   ASSERT_EQ(8u, I);
@@ -60,7 +60,7 @@ TEST(UseTest, sort) {
   });
   I = 0;
   for (User *U : X.users()) {
-    snprintf(vnbuf, sizeof(vnbuf), "v%u", (7 - I++));
+    format("v%u", (7 - I++)).snprint(vnbuf, sizeof(vnbuf));
     EXPECT_EQ(vnbuf, U->getName());
   }
   ASSERT_EQ(8u, I);
@@ -95,7 +95,7 @@ TEST(UseTest, reverse) {
   });
   unsigned I = 0;
   for (User *U : X.users()) {
-    snprintf(vnbuf, sizeof(vnbuf), "v%u", I++);
+    format("v%u", I++).snprint(vnbuf, sizeof(vnbuf));
     EXPECT_EQ(vnbuf, U->getName());
   }
   ASSERT_EQ(8u, I);
@@ -103,7 +103,7 @@ TEST(UseTest, reverse) {
   X.reverseUseList();
   I = 0;
   for (User *U : X.users()) {
-    snprintf(vnbuf, sizeof(vnbuf), "v%u", (7 - I++));
+    format("v%u", (7 - I++)).snprint(vnbuf, sizeof(vnbuf));
     EXPECT_EQ(vnbuf, U->getName());
   }
   ASSERT_EQ(8u, I);