svn commit: r363773 - projects/clang1100-import/contrib/llvm-project/compiler-rt/lib/builtins
Dimitry Andric
dim at FreeBSD.org
Sun Aug 2 18:07:17 UTC 2020
Author: dim
Date: Sun Aug 2 18:07:16 2020
New Revision: 363773
URL: https://svnweb.freebsd.org/changeset/base/363773
Log:
Reapply r230021, r276851 and a few other commits to compiler-rt
Reapply r230021 (by ed):
Add a workaround to prevent endless recursion in compiler-rt.
SPARC and MIPS CPUs don't have special instructions to count
leading/trailing zeroes. The compiler-rt library provides fallback
rountines for these. The 64-bit routines, __clzdi2 and __ctzdi2, are
implemented as simple wrappers around the compiler built-in
__builtin_clz(), assuming these will expand to either 32-bit
CPU instructions or calls to __clzsi2 and __ctzsi2.
Unfortunately, our GCC 4.2 probably thinks that because the operand is
stored in a 64-bit register, it might just be a better idea to invoke
its 64-bit equivalent, simply resulting into endless recursion. Fix this
by defining __builtin_clz and __builtin_ctz to __clzsi2 and __ctzsi2
explicitly.
Reapply r276851:
Update compiler-rt to trunk r224034. This brings a number of new
builtins, and also the various sanitizers. Support for these will be
added in a later commit.
Modified:
projects/clang1100-import/contrib/llvm-project/compiler-rt/lib/builtins/int_lib.h
Modified: projects/clang1100-import/contrib/llvm-project/compiler-rt/lib/builtins/int_lib.h
==============================================================================
--- projects/clang1100-import/contrib/llvm-project/compiler-rt/lib/builtins/int_lib.h Sun Aug 2 16:59:14 2020 (r363772)
+++ projects/clang1100-import/contrib/llvm-project/compiler-rt/lib/builtins/int_lib.h Sun Aug 2 18:07:16 2020 (r363773)
@@ -21,7 +21,9 @@
// ABI macro definitions
#if __ARM_EABI__
-#ifdef COMPILER_RT_ARMHF_TARGET
+#if defined(COMPILER_RT_ARMHF_TARGET) || (!defined(__clang__) && \
+ defined(__GNUC__) && (__GNUC__ < 4 || __GNUC__ == 4 && __GNUC_MINOR__ < 5))
+// The pcs attribute was introduced in GCC 4.5.0
#define COMPILER_RT_ABI
#else
#define COMPILER_RT_ABI __attribute__((__pcs__("aapcs")))
@@ -91,6 +93,29 @@
// Include internal utility function declarations.
#include "int_util.h"
+
+/*
+ * Workaround for LLVM bug 11663. Prevent endless recursion in
+ * __c?zdi2(), where calls to __builtin_c?z() are expanded to
+ * __c?zdi2() instead of __c?zsi2().
+ *
+ * Instead of placing this workaround in c?zdi2.c, put it in this
+ * global header to prevent other C files from making the detour
+ * through __c?zdi2() as well.
+ *
+ * This problem has been observed on FreeBSD for sparc64 and
+ * mips64 with GCC 4.2.1, and for riscv with GCC 5.2.0.
+ * Presumably it's any version of GCC, and targeting an arch that
+ * does not have dedicated bit counting instructions.
+ */
+#if defined(__FreeBSD__) && (defined(__sparc64__) || \
+ defined(__mips_n32) || defined(__mips_n64) || defined(__mips_o64) || \
+ defined(__riscv))
+si_int __clzsi2(si_int);
+si_int __ctzsi2(si_int);
+#define __builtin_clz __clzsi2
+#define __builtin_ctz __ctzsi2
+#endif /* FreeBSD && (sparc64 || mips_n32 || mips_n64 || mips_o64 || riscv) */
COMPILER_RT_ABI int __paritysi2(si_int a);
COMPILER_RT_ABI int __paritydi2(di_int a);
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