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-rw-r--r--build-aux/m4/bitcoin_runtime_lib.m442
1 files changed, 42 insertions, 0 deletions
diff --git a/build-aux/m4/bitcoin_runtime_lib.m4 b/build-aux/m4/bitcoin_runtime_lib.m4
new file mode 100644
index 0000000000..1a6922deca
--- /dev/null
+++ b/build-aux/m4/bitcoin_runtime_lib.m4
@@ -0,0 +1,42 @@
+# On some platforms clang builtin implementations
+# require compiler-rt as a runtime library to use.
+#
+# See:
+# - https://bugs.llvm.org/show_bug.cgi?id=28629
+
+m4_define([_CHECK_RUNTIME_testbody], [[
+ bool f(long long x, long long y, long long* p)
+ {
+ return __builtin_mul_overflow(x, y, p);
+ }
+ int main() { return 0; }
+]])
+
+AC_DEFUN([CHECK_RUNTIME_LIB], [
+
+ AC_LANG_PUSH([C++])
+
+ AC_MSG_CHECKING([for __builtin_mul_overflow])
+ AC_LINK_IFELSE(
+ [AC_LANG_SOURCE([_CHECK_RUNTIME_testbody])],
+ [
+ AC_MSG_RESULT([yes])
+ AC_DEFINE([HAVE_BUILTIN_MUL_OVERFLOW], [1], [Define if you have a working __builtin_mul_overflow])
+ ],
+ [
+ ax_check_save_flags="$LDFLAGS"
+ LDFLAGS="$LDFLAGS --rtlib=compiler-rt -lgcc_s"
+ AC_LINK_IFELSE(
+ [AC_LANG_SOURCE([_CHECK_RUNTIME_testbody])],
+ [
+ AC_MSG_RESULT([yes, with additional linker flags])
+ RUNTIME_LDFLAGS="--rtlib=compiler-rt -lgcc_s"
+ AC_DEFINE([HAVE_BUILTIN_MUL_OVERFLOW], [1], [Define if you have a working __builtin_mul_overflow])
+ ],
+ [AC_MSG_RESULT([no])])
+ LDFLAGS="$ax_check_save_flags"
+ ])
+
+ AC_LANG_POP
+ AC_SUBST([RUNTIME_LDFLAGS])
+])