Reapply "Make __gcov_flush flush counters for all shared libraries"

This reapplies r336365, after marking tests as failing on various
configurations.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@336678 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 80 insertions, 69 deletions

diff --git a/lib/profile/GCDAProfiling.c b/lib/profile/GCDAProfiling.c
index 68a0cab66..ad58db4c4 100644
--- a/lib/profile/GCDAProfiling.c
+++ b/lib/profile/GCDAProfiling.c
@@ -86,31 +86,76 @@ static uint64_t file_size = 0;
 static int new_file = 0;
 static int fd = -1;
 
-/*
- * A list of functions to write out the data.
- */
-typedef void (*writeout_fn)();
+typedef void (*fn_ptr)();
+
+typedef void* dynamic_object_id;
+// The address of this variable identifies a given dynamic object.
+static dynamic_object_id current_id;
+#define CURRENT_ID (&current_id)
 
-struct writeout_fn_node {
-  writeout_fn fn;
-  struct writeout_fn_node *next;
+struct fn_node {
+  dynamic_object_id id;
+  fn_ptr fn;
+  struct fn_node* next;
 };
 
-static struct writeout_fn_node *writeout_fn_head = NULL;
-static struct writeout_fn_node *writeout_fn_tail = NULL;
+struct fn_list {
+  struct fn_node *head, *tail;
+};
 
 /*
- *  A list of flush functions that our __gcov_flush() function should call.
+ * A list of functions to write out the data, shared between all dynamic objects.
  */
-typedef void (*flush_fn)();
+struct fn_list writeout_fn_list;
 
-struct flush_fn_node {
-  flush_fn fn;
-  struct flush_fn_node *next;
-};
+/*
+ *  A list of flush functions that our __gcov_flush() function should call, shared between all dynamic objects.
+ */
+struct fn_list flush_fn_list;
+
+static void fn_list_insert(struct fn_list* list, fn_ptr fn) {
+  struct fn_node* new_node = malloc(sizeof(struct fn_node));
+  new_node->fn = fn;
+  new_node->next = NULL;
+  new_node->id = CURRENT_ID;
+
+  if (!list->head) {
+    list->head = list->tail = new_node;
+  } else {
+    list->tail->next = new_node;
+    list->tail = new_node;
+  }
+}
+
+static void fn_list_remove(struct fn_list* list) {
+  struct fn_node* curr = list->head;
+  struct fn_node* prev = NULL;
+  struct fn_node* next = NULL;
+
+  while (curr) {
+    next = curr->next;
+
+    if (curr->id == CURRENT_ID) {
+      if (curr == list->head) {
+        list->head = next;
+      }
+
+      if (curr == list->tail) {
+        list->tail = prev;
+      }
 
-static struct flush_fn_node *flush_fn_head = NULL;
-static struct flush_fn_node *flush_fn_tail = NULL;
+      if (prev) {
+        prev->next = next;
+      }
+
+      free(curr);
+    } else {
+      prev = curr;
+    }
+
+    curr = next;
+  }
+}
 
 static void resize_write_buffer(uint64_t size) {
   if (!new_file) return;
@@ -403,6 +448,7 @@ void llvm_gcda_summary_info() {
   const uint32_t obj_summary_len = 9; /* Length for gcov compatibility. */
   uint32_t i;
   uint32_t runs = 1;
+  static uint32_t run_counted = 0; // We only want to increase the run count once.
   uint32_t val = 0;
   uint64_t save_cur_pos = cur_pos;
 
@@ -429,7 +475,9 @@ void llvm_gcda_summary_info() {
 
     read_32bit_value(); /* checksum, unused */
     read_32bit_value(); /* num, unused */
-    runs += read_32bit_value(); /* Add previous run count to new counter. */
+    uint32_t prev_runs = read_32bit_value();
+    /* Add previous run count to new counter, if not already counted before. */
+    runs = run_counted ? prev_runs : prev_runs + 1;
   }
 
   cur_pos = save_cur_pos;
@@ -447,6 +495,8 @@ void llvm_gcda_summary_info() {
   write_bytes("\0\0\0\xa3", 4); /* tag indicates 1 program */
   write_32bit_value(0); /* 0 length */
 
+  run_counted = 1;
+
 #ifdef DEBUG_GCDAPROFILING
   fprintf(stderr, "llvmgcda:   %u runs\n", runs);
 #endif
@@ -479,61 +529,34 @@ void llvm_gcda_end_file() {
 }
 
 COMPILER_RT_VISIBILITY
-void llvm_register_writeout_function(writeout_fn fn) {
-  struct writeout_fn_node *new_node = malloc(sizeof(struct writeout_fn_node));
-  new_node->fn = fn;
-  new_node->next = NULL;
-
-  if (!writeout_fn_head) {
-    writeout_fn_head = writeout_fn_tail = new_node;
-  } else {
-    writeout_fn_tail->next = new_node;
-    writeout_fn_tail = new_node;
-  }
+void llvm_register_writeout_function(fn_ptr fn) {
+  fn_list_insert(&writeout_fn_list, fn);
 }
 
 COMPILER_RT_VISIBILITY
 void llvm_writeout_files(void) {
-  struct writeout_fn_node *curr = writeout_fn_head;
+  struct fn_node *curr = writeout_fn_list.head;
 
   while (curr) {
-    curr->fn();
+    if (curr->id == CURRENT_ID) {
+      curr->fn();
+    }
     curr = curr->next;
   }
 }
 
 COMPILER_RT_VISIBILITY
 void llvm_delete_writeout_function_list(void) {
-  while (writeout_fn_head) {
-    struct writeout_fn_node *node = writeout_fn_head;
-    writeout_fn_head = writeout_fn_head->next;
-    free(node);
-  }
-  
-  writeout_fn_head = writeout_fn_tail = NULL;
+  fn_list_remove(&writeout_fn_list);
 }
 
 COMPILER_RT_VISIBILITY
-void llvm_register_flush_function(flush_fn fn) {
-  struct flush_fn_node *new_node = malloc(sizeof(struct flush_fn_node));
-  new_node->fn = fn;
-  new_node->next = NULL;
-
-  if (!flush_fn_head) {
-    flush_fn_head = flush_fn_tail = new_node;
-  } else {
-    flush_fn_tail->next = new_node;
-    flush_fn_tail = new_node;
-  }
+void llvm_register_flush_function(fn_ptr fn) {
+  fn_list_insert(&flush_fn_list, fn);
 }
 
-// __gcov_flush is hidden. When called in a .so file,
-// it dumps profile data of the calling .so file.
-// If a main program needs to dump profile data of each linked
-// .so files, it should use dlsym to find and call llvm_gcov_flush.
-COMPILER_RT_VISIBILITY
 void __gcov_flush() {
-  struct flush_fn_node *curr = flush_fn_head;
+  struct fn_node* curr = flush_fn_list.head;
 
   while (curr) {
     curr->fn();
@@ -541,25 +564,13 @@ void __gcov_flush() {
   }
 }
 
-// llvm_gcov_flush is not hidden for a program to use dlsym to
-// find and call for any linked .so file.
-void llvm_gcov_flush() {
-  __gcov_flush();
-}
-
 COMPILER_RT_VISIBILITY
 void llvm_delete_flush_function_list(void) {
-  while (flush_fn_head) {
-    struct flush_fn_node *node = flush_fn_head;
-    flush_fn_head = flush_fn_head->next;
-    free(node);
-  }
-
-  flush_fn_head = flush_fn_tail = NULL;
+  fn_list_remove(&flush_fn_list);
 }
 
 COMPILER_RT_VISIBILITY
-void llvm_gcov_init(writeout_fn wfn, flush_fn ffn) {
+void llvm_gcov_init(fn_ptr wfn, fn_ptr ffn) {
   static int atexit_ran = 0;
 
   if (wfn)