[PATCH 1/4] Cherry-pick fprofile-generate-atomic from google/gcc-4_9 branch

[marxin <mliska@suse.cz>]

libgcc/ChangeLog:

2016-07-28  Martin Liska  <mliska@suse.cz>

	* Makefile.in: Add functions to LIBGCOV_PROFILER.
	* libgcov-profiler.c (__gcov_one_value_profiler_body_atomic):
	New function.
	(__gcov_one_value_profiler_atomic): Likewise.
	(__gcov_indirect_call_profiler_v2): Fix GNU coding style.
	(__gcov_indirect_call_profiler_v2_atomic): New function.
	* libgcov.h: Declare __gcov_indirect_call_profiler_v2_atomic and
	__gcov_one_value_profiler_body_atomic.

gcc/ChangeLog:

2016-07-28  Martin Liska  <mliska@suse.cz>

	* common.opt (fprofile-generate-atomic): Add new flag.
	* gcov-io.h: Declare GCOV_TYPE_ATOMIC_FETCH_ADD and
	GCOV_TYPE_ATOMIC_FETCH_ADD_FN.
	* tree-profile.c (gimple_init_edge_profiler): Generate
	also atomic profiler update.
	(gimple_gen_edge_profiler): Likewise.
	* doc/invoke.texi: Document -fprofile-generate-atomic.

gcc/testsuite/ChangeLog:

2016-07-28  Martin Liska  <mliska@suse.cz>

	* g++.dg/gcov/gcov-threads-1.C: New test.
---
 gcc/common.opt                             |  9 +++++
 gcc/doc/invoke.texi                        | 11 ++++++
 gcc/gcov-io.h                              | 22 +++++++++++
 gcc/testsuite/g++.dg/gcov/gcov-threads-1.C | 46 ++++++++++++++++++++++
 gcc/tree-profile.c                         | 62 +++++++++++++++++++++---------
 libgcc/Makefile.in                         |  4 +-
 libgcc/libgcov-profiler.c                  | 42 +++++++++++++++++++-
 libgcc/libgcov.h                           |  2 +
 8 files changed, 177 insertions(+), 21 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/gcov/gcov-threads-1.C

diff --git a/gcc/common.opt b/gcc/common.opt
index 8a292ed..1adb1d7 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1916,6 +1916,15 @@ fprofile-correction
 Common Report Var(flag_profile_correction)
 Enable correction of flow inconsistent profile data input.
 
+; fprofile-generate-atomic=0: disable atomically update.
+; fprofile-generate-atomic=1: atomically update edge profile counters.
+; fprofile-generate-atomic=2: atomically update value profile counters.
+; fprofile-generate-atomic=3: atomically update edge and value profile counters.
+; other values will be ignored (fall back to the default of 0).
+fprofile-generate-atomic=
+Common Joined UInteger Report Var(flag_profile_gen_atomic) Init(0) Optimization
+fprofile-generate-atomic=[0..3] Atomically increments for profile counters.
+
 fprofile-generate
 Common
 Enable common options for generating profile info for profile feedback directed optimizations.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 22001f9..147b448 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -9933,6 +9933,17 @@ the profile feedback data files. See @option{-fprofile-dir}.
 To optimize the program based on the collected profile information, use
 @option{-fprofile-use}.  @xref{Optimize Options}, for more information.
 
+@item -fprofile-generate-atomic
+@opindex fprofile-generate-atomic
+
+Enable atomic increments for profile counters.  By default, an instrumented
+application can produce a corrupted profiled if it utilizes threads in
+a massive way.  The option provides atomic updates for edge profile counters
+(@option{-fprofile-generate-atomic=1}) and indirect call counters
+(@option{-fprofile-generate-atomic=2}).  Both can be enabled with
+(@option{-fprofile-generate-atomic=3}), default value of the option
+is equal to 0.
+
 @item -fsanitize=address
 @opindex fsanitize=address
 Enable AddressSanitizer, a fast memory error detector.
diff --git a/gcc/gcov-io.h b/gcc/gcov-io.h
index bbf013a..96ed78b 100644
--- a/gcc/gcov-io.h
+++ b/gcc/gcov-io.h
@@ -169,6 +169,19 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 
 typedef unsigned gcov_unsigned_t;
 typedef unsigned gcov_position_t;
+
+#if LONG_LONG_TYPE_SIZE > 32
+#define GCOV_TYPE_ATOMIC_FETCH_ADD_FN __atomic_fetch_add_8
+#define GCOV_TYPE_ATOMIC_FETCH_ADD BUILT_IN_ATOMIC_FETCH_ADD_8
+#else
+#define GCOV_TYPE_ATOMIC_FETCH_ADD_FN __atomic_fetch_add_4
+#define GCOV_TYPE_ATOMIC_FETCH_ADD BUILT_IN_ATOMIC_FETCH_ADD_4
+#endif
+#define PROFILE_GEN_EDGE_ATOMIC (flag_profile_gen_atomic == 1 || \
+				 flag_profile_gen_atomic == 3)
+#define PROFILE_GEN_VALUE_ATOMIC (flag_profile_gen_atomic == 2 || \
+				  flag_profile_gen_atomic == 3)
+
 /* gcov_type is typedef'd elsewhere for the compiler */
 #if IN_GCOV
 #define GCOV_LINKAGE static
@@ -196,6 +209,15 @@ typedef uint64_t gcov_type_unsigned;
 #endif
 
 #if IN_LIBGCOV
+
+#if LONG_LONG_TYPE_SIZE > 32
+#define GCOV_TYPE_ATOMIC_FETCH_ADD_FN __atomic_fetch_add_8
+#define GCOV_TYPE_ATOMIC_FETCH_ADD BUILT_IN_ATOMIC_FETCH_ADD_8
+#else
+#define GCOV_TYPE_ATOMIC_FETCH_ADD_FN __atomic_fetch_add_4
+#define GCOV_TYPE_ATOMIC_FETCH_ADD BUILT_IN_ATOMIC_FETCH_ADD_4
+#endif
+
 #define gcov_nonruntime_assert(EXPR) ((void)(0 && (EXPR)))
 #else
 #define gcov_nonruntime_assert(EXPR) gcc_assert (EXPR)
diff --git a/gcc/testsuite/g++.dg/gcov/gcov-threads-1.C b/gcc/testsuite/g++.dg/gcov/gcov-threads-1.C
new file mode 100644
index 0000000..184beb9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/gcov/gcov-threads-1.C
@@ -0,0 +1,46 @@
+/* { dg-options "-fprofile-arcs -ftest-coverage -pthread -fprofile-generate-atomic=3" } */
+/* { dg-do run { target native } } */
+
+#include <stdint.h>
+#include <pthread.h>
+#include <assert.h>
+
+#define NR 5
+
+pthread_mutex_t cndMs[NR];
+static void *ContentionNoDeadlock_thread(void *start)
+{
+  for (uint32_t k = 0; k < 100000; ++k)		/* count(500005) */
+    {
+      int starti = *(int*)start;		/* count(500000) */
+      for (uint32_t i = starti; i < NR; ++i) 
+	pthread_mutex_lock (&cndMs[i]);
+      for (int32_t i = NR - 1; i >= starti; --i)
+	pthread_mutex_unlock (&cndMs[i]);
+  }
+}
+int main(int argc, char **argv) {
+  for (unsigned i = 0; i < NR; i++)
+    cndMs[i] = PTHREAD_MUTEX_INITIALIZER;
+
+  pthread_t t[NR];
+  int ids[NR];
+
+  for (int i = 0; i < NR; i++)
+  {
+    ids[i] = i;
+    int r = pthread_create (&t[i], NULL, ContentionNoDeadlock_thread, &ids[i]);
+    assert (r == 0);				/* count(5) */
+  }
+
+  int ret;
+  for (int i = 0; i < NR; i++)
+    {
+      int r = pthread_join (t[i], (void**)&ret);
+      assert (r == 0);				/* count(5) */
+    }
+
+  return 0;					/* count(1) */
+}
+
+/* { dg-final { run-gcov gcov-threads-1.C } } */
diff --git a/gcc/tree-profile.c b/gcc/tree-profile.c
index 39fe15f..2c6fbd1 100644
--- a/gcc/tree-profile.c
+++ b/gcc/tree-profile.c
@@ -164,7 +164,12 @@ gimple_init_edge_profiler (void)
 	      = build_function_type_list (void_type_node,
 					  gcov_type_ptr, gcov_type_node,
 					  NULL_TREE);
-      tree_one_value_profiler_fn
+      if (PROFILE_GEN_VALUE_ATOMIC)
+	tree_one_value_profiler_fn
+	      = build_fn_decl ("__gcov_one_value_profiler_atomic",
+				     one_value_profiler_fn_type);
+      else
+	tree_one_value_profiler_fn
 	      = build_fn_decl ("__gcov_one_value_profiler",
 				     one_value_profiler_fn_type);
       TREE_NOTHROW (tree_one_value_profiler_fn) = 1;
@@ -180,11 +185,14 @@ gimple_init_edge_profiler (void)
 					  gcov_type_node,
 					  ptr_void,
 					  NULL_TREE);
+      const char *profiler_fn_name = "__gcov_indirect_call_profiler_v2";
+      if (PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE))
+	profiler_fn_name = "__gcov_indirect_call_topn_profiler";
+      if (PROFILE_GEN_VALUE_ATOMIC)
+	profiler_fn_name = "__gcov_indirect_call_profiler_v2_atomic";
+
       tree_indirect_call_profiler_fn
-	      = build_fn_decl ( (PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE) ?
-				 "__gcov_indirect_call_topn_profiler":
-				 "__gcov_indirect_call_profiler_v2"),
-			       ic_profiler_fn_type);
+	      = build_fn_decl (profiler_fn_name, ic_profiler_fn_type);
 
       TREE_NOTHROW (tree_indirect_call_profiler_fn) = 1;
       DECL_ATTRIBUTES (tree_indirect_call_profiler_fn)
@@ -241,22 +249,38 @@ gimple_init_edge_profiler (void)
 void
 gimple_gen_edge_profiler (int edgeno, edge e)
 {
-  tree ref, one, gcov_type_tmp_var;
-  gassign *stmt1, *stmt2, *stmt3;
+  tree one;
+  bool is_atomic = PROFILE_GEN_EDGE_ATOMIC;
 
-  ref = tree_coverage_counter_ref (GCOV_COUNTER_ARCS, edgeno);
   one = build_int_cst (gcov_type_node, 1);
-  gcov_type_tmp_var = make_temp_ssa_name (gcov_type_node,
-					  NULL, "PROF_edge_counter");
-  stmt1 = gimple_build_assign (gcov_type_tmp_var, ref);
-  gcov_type_tmp_var = make_temp_ssa_name (gcov_type_node,
-					  NULL, "PROF_edge_counter");
-  stmt2 = gimple_build_assign (gcov_type_tmp_var, PLUS_EXPR,
-			       gimple_assign_lhs (stmt1), one);
-  stmt3 = gimple_build_assign (unshare_expr (ref), gimple_assign_lhs (stmt2));
-  gsi_insert_on_edge (e, stmt1);
-  gsi_insert_on_edge (e, stmt2);
-  gsi_insert_on_edge (e, stmt3);
+
+  if (is_atomic)
+    {
+      /* __atomic_fetch_add (&counter, 1, MEMMODEL_RELAXED); */
+      tree addr = tree_coverage_counter_addr (GCOV_COUNTER_ARCS, edgeno);
+      gcall *stmt
+	= gimple_build_call (builtin_decl_explicit (GCOV_TYPE_ATOMIC_FETCH_ADD),
+			     3, addr, one,
+			     build_int_cst (integer_type_node,
+					    MEMMODEL_RELAXED));
+      gsi_insert_on_edge (e, stmt);
+    }
+  else
+    {
+      tree ref = tree_coverage_counter_ref (GCOV_COUNTER_ARCS, edgeno);
+      tree gcov_type_tmp_var = make_temp_ssa_name (gcov_type_node,
+						   NULL, "PROF_edge_counter");
+      gassign *stmt1 = gimple_build_assign (gcov_type_tmp_var, ref);
+      gcov_type_tmp_var = make_temp_ssa_name (gcov_type_node,
+					      NULL, "PROF_edge_counter");
+      gassign *stmt2 = gimple_build_assign (gcov_type_tmp_var, PLUS_EXPR,
+					    gimple_assign_lhs (stmt1), one);
+      gassign *stmt3 = gimple_build_assign (unshare_expr (ref),
+					    gimple_assign_lhs (stmt2));
+      gsi_insert_on_edge (e, stmt1);
+      gsi_insert_on_edge (e, stmt2);
+      gsi_insert_on_edge (e, stmt3);
+    }
 }
 
 /* Emits code to get VALUE to instrument at GSI, and returns the
diff --git a/libgcc/Makefile.in b/libgcc/Makefile.in
index f09b39b..8b0fdd9 100644
--- a/libgcc/Makefile.in
+++ b/libgcc/Makefile.in
@@ -860,8 +860,10 @@ LIBGCOV_MERGE = _gcov_merge_add _gcov_merge_single _gcov_merge_delta	\
 	_gcov_merge_ior _gcov_merge_time_profile _gcov_merge_icall_topn
 LIBGCOV_PROFILER = _gcov_interval_profiler _gcov_pow2_profiler		\
 	_gcov_one_value_profiler _gcov_indirect_call_profiler		\
+	_gcov_one_value_profiler_atomic					\
  	_gcov_average_profiler _gcov_ior_profiler			\
-	_gcov_indirect_call_profiler_v2 _gcov_time_profiler		\
+	_gcov_indirect_call_profiler_v2					\
+	_gcov_time_profiler						\
 	_gcov_indirect_call_topn_profiler
 LIBGCOV_INTERFACE = _gcov_dump _gcov_flush _gcov_fork			\
 	_gcov_execl _gcov_execlp					\
diff --git a/libgcc/libgcov-profiler.c b/libgcc/libgcov-profiler.c
index e947188..1b307ac 100644
--- a/libgcc/libgcov-profiler.c
+++ b/libgcc/libgcov-profiler.c
@@ -93,6 +93,31 @@ __gcov_one_value_profiler (gcov_type *counters, gcov_type value)
 }
 #endif
 
+/* Atomic update version of __gcov_one_value_profile_body().  */
+
+static inline void
+__gcov_one_value_profiler_body_atomic (gcov_type *counters, gcov_type value)
+{
+  if (value == counters[0])
+    GCOV_TYPE_ATOMIC_FETCH_ADD_FN (&counters[1], 1, MEMMODEL_RELAXED);
+  else if (counters[1] == 0)
+    {
+      counters[1] = 1;
+      counters[0] = value;
+    }
+  else
+    GCOV_TYPE_ATOMIC_FETCH_ADD_FN (&counters[1], -1, MEMMODEL_RELAXED);
+  GCOV_TYPE_ATOMIC_FETCH_ADD_FN (&counters[2], 1, MEMMODEL_RELAXED);
+}
+
+#ifdef L_gcov_one_value_profiler_atomic
+void
+__gcov_one_value_profiler_atomic (gcov_type *counters, gcov_type value)
+{
+  __gcov_one_value_profiler_body_atomic (counters, value);
+}
+#endif
+
 #ifdef L_gcov_indirect_call_topn_profiler
 /* Tries to keep track the most frequent N values in the counters where
    N is specified by parameter TOPN_VAL. To track top N values, 2*N counter
@@ -229,6 +254,7 @@ __gcov_indirect_call_topn_profiler (gcov_type value, void* cur_func)
 	  && *(void **) cur_func == *(void **) callee_func))
     __gcov_topn_value_profiler_body (__gcov_indirect_call_topn_counters, value);
 }
+
 #endif
 
 #ifdef L_gcov_indirect_call_profiler
@@ -291,9 +317,23 @@ __gcov_indirect_call_profiler_v2 (gcov_type value, void* cur_func)
      the descriptors to see if they point to the same function.  */
   if (cur_func == __gcov_indirect_call_callee
       || (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && __gcov_indirect_call_callee
-          && *(void **) cur_func == *(void **) __gcov_indirect_call_callee))
+	  && *(void **) cur_func == *(void **) __gcov_indirect_call_callee))
     __gcov_one_value_profiler_body (__gcov_indirect_call_counters, value);
 }
+
+/* Atomic update version of __gcov_indirect_call_profiler_v2().  */
+void
+__gcov_indirect_call_profiler_v2_atomic (gcov_type value, void* cur_func)
+{
+  /* If the C++ virtual tables contain function descriptors then one
+     function may have multiple descriptors and we need to dereference
+     the descriptors to see if they point to the same function.  */
+  if (cur_func == __gcov_indirect_call_callee
+      || (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && __gcov_indirect_call_callee
+	  && *(void **) cur_func == *(void **) __gcov_indirect_call_callee))
+    __gcov_one_value_profiler_body_atomic (__gcov_indirect_call_counters,
+					   value);
+}
 #endif
 
 #ifdef L_gcov_time_profiler
diff --git a/libgcc/libgcov.h b/libgcc/libgcov.h
index ae77998..0bd905b 100644
--- a/libgcc/libgcov.h
+++ b/libgcc/libgcov.h
@@ -270,9 +270,11 @@ extern void __gcov_merge_icall_topn (gcov_type *, unsigned) ATTRIBUTE_HIDDEN;
 extern void __gcov_interval_profiler (gcov_type *, gcov_type, int, unsigned);
 extern void __gcov_pow2_profiler (gcov_type *, gcov_type);
 extern void __gcov_one_value_profiler (gcov_type *, gcov_type);
+extern void __gcov_one_value_profiler_atomic (gcov_type *, gcov_type);
 extern void __gcov_indirect_call_profiler (gcov_type*, gcov_type,
                                            void*, void*);
 extern void __gcov_indirect_call_profiler_v2 (gcov_type, void *);
+extern void __gcov_indirect_call_profiler_v2_atomic (gcov_type, void *);
 extern void __gcov_time_profiler (gcov_type *);
 extern void __gcov_average_profiler (gcov_type *, gcov_type);
 extern void __gcov_ior_profiler (gcov_type *, gcov_type);
-- 
2.9.2