Debug build broken on v18.8.0

[trevnorris]

Version

v18.8.0

Platform

Linux pop-os 5.18.10-76051810-generic

Subsystem

build

What steps will reproduce the bug?

$ ./configure --debug
$ make

How often does it reproduce? Is there a required condition?

Every time when compiling with clang. The debug build completes when using gcc.

What is the expected behavior?

To build properly.

What do you see instead?

The following output during the build:

../deps/v8/src/codegen/register.h:29:48: error: member reference base type 'RegListBase' is not a structure or union
  int num_different_regs = RegListBase{regs...}.Count();
                           ~~~~~~~~~~~~~~~~~~~~^~~~~~

Additional information

I'm compiling with clang 11.1.0 and gcc 11.2.0.

[bnoordhuis]

Hi Trevor, long time no see! Does it work when you apply this patch?

diff --git a/src/codegen/register.h b/src/codegen/register.h
index e36e4d1e9af..36561fe5077 100644
--- a/deps/v8/src/codegen/register.h
+++ b/deps/v8/src/codegen/register.h
@@ -19,18 +19,17 @@ constexpr bool ShouldPadArguments(int argument_count) {
   return ArgumentPaddingSlots(argument_count) != 0;
 }
 
 #ifdef DEBUG
 template <typename... RegTypes,
           // All arguments must be either Register or DoubleRegister.
           typename = typename std::enable_if_t<
               std::conjunction_v<std::is_same<Register, RegTypes>...> ||
               std::conjunction_v<std::is_same<DoubleRegister, RegTypes>...>>>
 inline constexpr bool AreAliased(RegTypes... regs) {
-  int num_different_regs = RegListBase{regs...}.Count();
+  using FirstRegType = std::tuple_element_t<0, std::tuple<RegTypes...>>;
+  int num_different_regs = RegListBase<FirstRegType>{regs...}.Count();
   int num_given_regs = (... + (regs.is_valid() ? 1 : 0));
   return num_different_regs < num_given_regs;
 }
 #endif

 }  // namespace internal
 }  // namespace v8

[trevnorris]

Hey Ben! It has been a while. That patch does fix the Debug build issue. Thanks.