[PATCH 0/1] MR10178: compiler-rt: add __ctzdi2 to fix i386 mingw builds

[Maotong Zhang (＠xiaotong)]

Commit 8d8d871b switched mingw from -lgcc to compiler-rt.
This breaks i386 builds with ccache: Capstone fails to link
(AArch64/ARM disassemblers) due to an undefined __ctzdi2 symbol.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10178

[PATCH 1/1] compiler-rt: add __ctzdi2 to fix i386 MinGW builds

[Maotong Zhang]

From: Maotong Zhang <[e-mail]>

Commit 8d8d871b switched mingw from -lgcc to compiler-rt.
This breaks i386 builds with ccache: Capstone fails to link
(AArch64/ARM disassemblers) due to an undefined __ctzdi2 symbol.
---
 libs/compiler-rt/Makefile.in           |  1 +
 libs/compiler-rt/lib/builtins/ctzdi2.c | 40 ++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100644 libs/compiler-rt/lib/builtins/ctzdi2.c

diff --git a/libs/compiler-rt/Makefile.in b/libs/compiler-rt/Makefile.in
index d0cc171ccbd..85757c21a47 100644
--- a/libs/compiler-rt/Makefile.in
+++ b/libs/compiler-rt/Makefile.in
@@ -7,6 +7,7 @@ SOURCES = \
 	lib/builtins/arm/aeabi_uldivmod.S \
 	lib/builtins/arm/divmodsi4.S \
 	lib/builtins/arm/udivmodsi4.S \
+	lib/builtins/ctzdi2.c \
 	lib/builtins/divdi3.c \
 	lib/builtins/divmoddi4.c \
 	lib/builtins/divmodsi4.c \
diff --git a/libs/compiler-rt/lib/builtins/ctzdi2.c b/libs/compiler-rt/lib/builtins/ctzdi2.c
new file mode 100644
index 00000000000..ef6d7fea136
--- /dev/null
+++ b/libs/compiler-rt/lib/builtins/ctzdi2.c
@@ -0,0 +1,40 @@
+/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file implements __ctzdi2 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+#include "int_lib.h"
+
+/* Returns: the number of trailing 0-bits  */
+
+#if !defined(__clang__) &&                                                     \
+    ((defined(__sparc__) && defined(__arch64__)) ||                            \
+     defined(__mips64) ||                                                      \
+     (defined(__riscv) && __SIZEOF_POINTER__ >= 8))
+/* On 64-bit architectures with neither a native clz instruction nor a native
+ * ctz instruction, gcc resolves __builtin_ctz to __ctzdi2 rather than
+ * __ctzsi2, leading to infinite recursion. */
+#define __builtin_ctz(a) __ctzsi2(a)
+extern si_int __ctzsi2(si_int);
+#endif
+
+/* Precondition: a != 0 */
+
+COMPILER_RT_ABI si_int
+__ctzdi2(di_int a)
+{
+    dwords x;
+    x.all = a;
+    const si_int f = -(x.s.low == 0);
+    return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) +
+              (f & ((si_int)(sizeof(si_int) * CHAR_BIT)));
+}
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10178