[SystemZ] Support transactional execution on zEC12

The zEC12 provides the transactional-execution facility.  This is exposed
to users via a set of builtin routines on other compilers.  This patch
adds clang support to enable those builtins.  In partciular, the patch:

- enables the transactional-execution feature by default on zEC12
- allows to override presence of that feature via the -mhtm/-mno-htm options
- adds a predefined macro __HTM__ if the feature is enabled
- adds support for the transactional-execution GCC builtins
- adds Sema checking to verify the __builtin_tabort abort code
- adds the s390intrin.h header file (for GCC compatibility)
- adds s390 sections to the htmintrin.h and htmxlintrin.h header files

Since this is first use of target-specific intrinsics on the platform,
the patch creates the include/clang/Basic/BuiltinsSystemZ.def file and
hooks it up in TargetBuiltins.h and lib/Basic/Targets.cpp.

An associated LLVM patch adds the required LLVM IR intrinsics.

For reference, the transactional-execution instructions are documented
in the z/Architecture Principles of Operation for the zEC12:
http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/download/DZ9ZR009.pdf
The associated builtins are documented in the GCC manual:
http://gcc.gnu.org/onlinedocs/gcc/S_002f390-System-z-Built-in-Functions.html
The htmxlintrin.h intrinsics provided for compatibility with the IBM XL
compiler are documented in the "z/OS XL C/C++ Programming Guide".

llvm-svn: 233804

1 files changed, 95 insertions, 0 deletions

diff --git a/clang/lib/Headers/htmintrin.h b/clang/lib/Headers/htmintrin.h
index 4598ee06b50..0088c7ccab9 100644
--- a/clang/lib/Headers/htmintrin.h
+++ b/clang/lib/Headers/htmintrin.h
@@ -128,4 +128,99 @@ typedef uintptr_t tfhar_t;
 
 #endif /* __powerpc */
 
+#ifdef __s390__
+
+/* Condition codes generated by tbegin  */
+#define _HTM_TBEGIN_STARTED       0
+#define _HTM_TBEGIN_INDETERMINATE 1
+#define _HTM_TBEGIN_TRANSIENT     2
+#define _HTM_TBEGIN_PERSISTENT    3
+
+/* The abort codes below this threshold are reserved for machine use.  */
+#define _HTM_FIRST_USER_ABORT_CODE 256
+
+/* The transaction diagnostic block is it is defined in the Principles
+   of Operation chapter 5-91.  */
+
+struct __htm_tdb {
+  unsigned char format;                /*   0 */
+  unsigned char flags;
+  unsigned char reserved1[4];
+  unsigned short nesting_depth;
+  unsigned long long abort_code;       /*   8 */
+  unsigned long long conflict_token;   /*  16 */
+  unsigned long long atia;             /*  24 */
+  unsigned char eaid;                  /*  32 */
+  unsigned char dxc;
+  unsigned char reserved2[2];
+  unsigned int program_int_id;
+  unsigned long long exception_id;     /*  40 */
+  unsigned long long bea;              /*  48 */
+  unsigned char reserved3[72];         /*  56 */
+  unsigned long long gprs[16];         /* 128 */
+} __attribute__((__packed__, __aligned__ (8)));
+
+
+/* Helper intrinsics to retry tbegin in case of transient failure.  */
+
+static __inline int __attribute__((__always_inline__, __nodebug__))
+__builtin_tbegin_retry_null (int retry)
+{
+  int cc, i = 0;
+
+  while ((cc = __builtin_tbegin(0)) == _HTM_TBEGIN_TRANSIENT
+         && i++ < retry)
+    __builtin_tx_assist(i);
+
+  return cc;
+}
+
+static __inline int __attribute__((__always_inline__, __nodebug__))
+__builtin_tbegin_retry_tdb (void *tdb, int retry)
+{
+  int cc, i = 0;
+
+  while ((cc = __builtin_tbegin(tdb)) == _HTM_TBEGIN_TRANSIENT
+         && i++ < retry)
+    __builtin_tx_assist(i);
+
+  return cc;
+}
+
+#define __builtin_tbegin_retry(tdb, retry) \
+  (__builtin_constant_p(tdb == 0) && tdb == 0 ? \
+   __builtin_tbegin_retry_null(retry) : \
+   __builtin_tbegin_retry_tdb(tdb, retry))
+
+static __inline int __attribute__((__always_inline__, __nodebug__))
+__builtin_tbegin_retry_nofloat_null (int retry)
+{
+  int cc, i = 0;
+
+  while ((cc = __builtin_tbegin_nofloat(0)) == _HTM_TBEGIN_TRANSIENT
+         && i++ < retry)
+    __builtin_tx_assist(i);
+
+  return cc;
+}
+
+static __inline int __attribute__((__always_inline__, __nodebug__))
+__builtin_tbegin_retry_nofloat_tdb (void *tdb, int retry)
+{
+  int cc, i = 0;
+
+  while ((cc = __builtin_tbegin_nofloat(tdb)) == _HTM_TBEGIN_TRANSIENT
+         && i++ < retry)
+    __builtin_tx_assist(i);
+
+  return cc;
+}
+
+#define __builtin_tbegin_retry_nofloat(tdb, retry) \
+  (__builtin_constant_p(tdb == 0) && tdb == 0 ? \
+   __builtin_tbegin_retry_nofloat_null(retry) : \
+   __builtin_tbegin_retry_nofloat_tdb(tdb, retry))
+
+#endif /* __s390__ */
+
 #endif /* __HTMINTRIN_H */