Skip to content

Work around clang hang compiling interp.c with -O1 and higher #5

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
guillerodriguez merged 1 commit into from
Feb 5, 2026
Merged

Work around clang hang compiling interp.c with -O1 and higher #5

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 20 additions & 0 deletions configure.ac
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -254,6 +254,26 @@ dnl Checks for programs.
AC_PROG_CC
AM_PROG_AS

dnl Check if we're using clang - needed for workarounds
AC_MSG_CHECKING([whether compiler is clang])
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([], [[
#ifndef __clang__
#error not clang
#endif
]])],
[using_clang=yes],
[using_clang=no])
AC_MSG_RESULT([$using_clang])

dnl Clang's TailDuplication pass has exponential time complexity with the
dnl computed goto dispatch pattern used in the interpreter. Disable tail
dnl duplication (for interp.c only) to prevent the hang while keeping all
dnl other LLVM optimizations intact.
if test "$using_clang" = yes; then
interp_cflags="$interp_cflags -mllvm -tail-dup-limit=0"
fi

AC_CHECK_PROGS(JAVAC, ecj jikes "gcj -C" javac)

dnl Checks for libraries.
Expand Down