[cleanup] Make {AreAliased} generic and variadic

This allows to have only one version of {AreAliased} which has a
clean implementation.

R=mstarzinger@chromium.org

Bug: v8:8015
Change-Id: I25c64a8c2077383129548773319799fac768521e
Reviewed-on: https://chromium-review.googlesource.com/1167290
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55007}

src/base/template-utils.h

@@ -114,6 +114,16 @@ constexpr auto fold(Func func, Ts&&... more) ->
                                                 std::forward<Ts>(more)...);
 }
 
+// {is_same<Ts...>::value} is true if all Ts are the same, false otherwise.
+template <typename... Ts>
+struct is_same : public std::false_type {};
+template <>
+struct is_same<> : public std::true_type {};
+template <typename T>
+struct is_same<T> : public std::true_type {};
+template <typename T, typename... Ts>
+struct is_same<T, T, Ts...> : public is_same<T, Ts...> {};
+
 }  // namespace base
 }  // namespace v8
 

src/turbo-assembler.cc

@@ -130,58 +130,5 @@ void TurboAssemblerBase::RecordCommentForOffHeapTrampoline(int builtin_index) {
   RecordComment(buffer_start);
 }
 
-#ifdef DEBUG
-
-bool AreAliased(Register reg1, Register reg2, Register reg3, Register reg4,
-                Register reg5, Register reg6, Register reg7, Register reg8,
-                Register reg9, Register reg10) {
-  int n_of_valid_regs = reg1.is_valid() + reg2.is_valid() + reg3.is_valid() +
-                        reg4.is_valid() + reg5.is_valid() + reg6.is_valid() +
-                        reg7.is_valid() + reg8.is_valid() + reg9.is_valid() +
-                        reg10.is_valid();
-
-  RegList regs = 0;
-  if (reg1.is_valid()) regs |= reg1.bit();
-  if (reg2.is_valid()) regs |= reg2.bit();
-  if (reg3.is_valid()) regs |= reg3.bit();
-  if (reg4.is_valid()) regs |= reg4.bit();
-  if (reg5.is_valid()) regs |= reg5.bit();
-  if (reg6.is_valid()) regs |= reg6.bit();
-  if (reg7.is_valid()) regs |= reg7.bit();
-  if (reg8.is_valid()) regs |= reg8.bit();
-  if (reg9.is_valid()) regs |= reg9.bit();
-  if (reg10.is_valid()) regs |= reg10.bit();
-  int n_of_non_aliasing_regs = NumRegs(regs);
-
-  return n_of_valid_regs != n_of_non_aliasing_regs;
-}
-
-bool AreAliased(DoubleRegister reg1, DoubleRegister reg2, DoubleRegister reg3,
-                DoubleRegister reg4, DoubleRegister reg5, DoubleRegister reg6,
-                DoubleRegister reg7, DoubleRegister reg8, DoubleRegister reg9,
-                DoubleRegister reg10) {
-  int n_of_valid_regs = reg1.is_valid() + reg2.is_valid() + reg3.is_valid() +
-                        reg4.is_valid() + reg5.is_valid() + reg6.is_valid() +
-                        reg7.is_valid() + reg8.is_valid() + reg9.is_valid() +
-                        reg10.is_valid();
-
-  RegList regs = 0;
-  if (reg1.is_valid()) regs |= reg1.bit();
-  if (reg2.is_valid()) regs |= reg2.bit();
-  if (reg3.is_valid()) regs |= reg3.bit();
-  if (reg4.is_valid()) regs |= reg4.bit();
-  if (reg5.is_valid()) regs |= reg5.bit();
-  if (reg6.is_valid()) regs |= reg6.bit();
-  if (reg7.is_valid()) regs |= reg7.bit();
-  if (reg8.is_valid()) regs |= reg8.bit();
-  if (reg9.is_valid()) regs |= reg9.bit();
-  if (reg10.is_valid()) regs |= reg10.bit();
-  int n_of_non_aliasing_regs = NumRegs(regs);
-
-  return n_of_valid_regs != n_of_non_aliasing_regs;
-}
-
-#endif  // DEBUG
-
 }  // namespace internal
 }  // namespace v8

src/turbo-assembler.h

@@ -6,6 +6,7 @@
 #define V8_TURBO_ASSEMBLER_H_
 
 #include "src/assembler-arch.h"
+#include "src/base/template-utils.h"
 #include "src/heap/heap.h"
 
 namespace v8 {
@@ -116,16 +117,16 @@ class HardAbortScope BASE_EMBEDDED {
 enum class StubCallMode { kCallOnHeapBuiltin, kCallWasmRuntimeStub };
 
 #ifdef DEBUG
-bool AreAliased(Register reg1, Register reg2, Register reg3 = no_reg,
-                Register reg4 = no_reg, Register reg5 = no_reg,
-                Register reg6 = no_reg, Register reg7 = no_reg,
-                Register reg8 = no_reg, Register reg9 = no_reg,
-                Register reg10 = no_reg);
-bool AreAliased(DoubleRegister reg1, DoubleRegister reg2,
-                DoubleRegister reg3 = no_dreg, DoubleRegister reg4 = no_dreg,
-                DoubleRegister reg5 = no_dreg, DoubleRegister reg6 = no_dreg,
-                DoubleRegister reg7 = no_dreg, DoubleRegister reg8 = no_dreg,
-                DoubleRegister reg9 = no_dreg, DoubleRegister reg10 = no_dreg);
+template <typename RegType, typename... RegTypes,
+          // All arguments must be either Register or DoubleRegister.
+          typename = typename std::enable_if<
+              base::is_same<Register, RegType, RegTypes...>::value ||
+              base::is_same<DoubleRegister, RegType, RegTypes...>::value>::type>
+inline bool AreAliased(RegType first_reg, RegTypes... regs) {
+  int num_different_regs = NumRegs(RegType::ListOf(first_reg, regs...));
+  int num_given_regs = sizeof...(regs) + 1;
+  return num_different_regs < num_given_regs;
+}
 #endif
 
 }  // namespace internal