Support code coverage in extended modules.

    - Reduce optimization (to -Os) to fit when doing coverage profile.
    - Remove errl storage area from base image.
    - Add GCC function attributes to sys library functions.

RTC: 36933
Change-Id: Ic83011a2444ef5b735db0446a14a0af34187eebf
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/1908
Tested-by: Jenkins Server
Reviewed-by: Brian H. Horton <brianh@linux.ibm.com>
Reviewed-by: ADAM R. MUHLE <armuhle@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>
Reviewed-by: Melissa J. Connell <missyc@us.ibm.com>
Reviewed-by: Paul Nguyen <nguyenp@us.ibm.com>
Reviewed-by: A. Patrick Williams III <iawillia@us.ibm.com>

1 files changed, 112 insertions, 29 deletions

diff --git a/src/include/usr/gcov.h b/src/include/usr/gcov.h
index dd249e1d5..a8e20f4fc 100644
--- a/src/include/usr/gcov.h
+++ b/src/include/usr/gcov.h
@@ -1,25 +1,25 @@
-//  IBM_PROLOG_BEGIN_TAG
-//  This is an automatically generated prolog.
-//
-//  $Source: src/include/usr/gcov.h $
-//
-//  IBM CONFIDENTIAL
-//
-//  COPYRIGHT International Business Machines Corp. 2012
-//
-//  p1
-//
-//  Object Code Only (OCO) source materials
-//  Licensed Internal Code Source Materials
-//  IBM HostBoot Licensed Internal Code
-//
-//  The source code for this program is not published or other-
-//  wise divested of its trade secrets, irrespective of what has
-//  been deposited with the U.S. Copyright Office.
-//
-//  Origin: 30
-//
-//  IBM_PROLOG_END
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/include/usr/gcov.h $                                      */
+/*                                                                        */
+/* IBM CONFIDENTIAL                                                       */
+/*                                                                        */
+/* COPYRIGHT International Business Machines Corp. 2012                   */
+/*                                                                        */
+/* p1                                                                     */
+/*                                                                        */
+/* Object Code Only (OCO) source materials                                */
+/* Licensed Internal Code Source Materials                                */
+/* IBM HostBoot Licensed Internal Code                                    */
+/*                                                                        */
+/* The source code for this program is not published or otherwise         */
+/* divested of its trade secrets, irrespective of what has been           */
+/* deposited with the U.S. Copyright Office.                              */
+/*                                                                        */
+/* Origin: 30                                                             */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
 #ifndef __USR_GCOV_H
 #define __USR_GCOV_H
 
@@ -37,31 +37,54 @@
  */
 
 #include <stddef.h>
+#include <stdint.h>
+#include <string.h>
 
 /** @struct gcov_info
  *  @brief Structure generated by gcc.  Do not use.
  *
  *  This structure is automatically generated and instances of it created by
  *  gcc when the --coverage compile option is used.  We don't need to
- *  manipulate this structure from code except to fix up the chains as objects
- *  are added to the chain.  The rest of this structure is parsed by the
- *  Gcov.pm debug tool.
+ *  manipulate this structure from code except:
+ *      1) To fix up the chains as objects are added to the chain.
+ *      2) To copy the gcov_info and counters into the base-chain when we
+ *         unload a module.
+ *
+ *  The rest of this structure is parsed by the Gcov.pm debug tool.
+ *
+ *  Most of the items in here are used as uint32_t's by gcov but are still
+ *  aligned on a 64-bit boundary.  The unusedN fields are to ensure proper
+ *  alignment.
  */
 struct gcov_info
 {
-    unsigned int version;  // Purposefully chose 'unsigned int' to match gcc.
+    uint32_t version;
+    uint32_t unused0;
     gcov_info* next;
-    // Really there is more after here in the structure, but this is all
-    // we care about from an in-memory perspective.
-};
+    uint32_t timestamp;
+    uint32_t unused1;
+    char* filename;
+    uint32_t n_functions;
+    uint32_t unused2;
+    void* functions;
+    uint32_t counter_mask;
+    uint32_t unused3;
+    uint32_t n_counters;
+    uint32_t unused4;
+    uint64_t* counters;
+} PACKED;
 
 // Preprocessor magic to create a variable name based off the module name.
 // GCOV_INFO_OBJ() will create a post-processed name like
 // 'foobar_gcov_info_head' or 'core_gcov_info_head'.
 #ifdef __HOSTBOOT_MODULE
     #define __GCOV_PREFIX __HOSTBOOT_MODULE
+    #define ___GCOV_STRINGIFY(X) #X
+    #define __GCOV_STRINGIFY(X) ___GCOV_STRINGIFY(X)
+    #define __GCOV_PREFIX_NAME __GCOV_STRINGIFY(__HOSTBOOT_MODULE)
 #else
     #define __GCOV_PREFIX core
+    #define __GCOV_PREFIX_NAME "core"
 #endif
 
 #define __GCOV_INFO_OBJ(X,Y) X ## Y
@@ -85,6 +108,66 @@ void __gcov_init(gcov_info* i_info)
                                            i_info->next, i_info));
 }
 
+// This ifdef has two pieces of code which are used in module unloading.
+//
+// In the modules themselves we have a function that is registered via atexit
+// to call to copy the contents of their own gcov_info chain into the base
+// gcov_info chain.  This is required because the module's memory is going
+// away as it is unloaded.
+//
+// In the base code (non-modules) we have a single implementation of the
+// code for actually doing a copy of the gcov_info chain into the base code's
+// own chain.  This is kept in just the base code for space savings.
+//
+#ifdef __HOSTBOOT_MODULE
+// Forward declaration of __gcov_module_copychain for modules.
+extern "C" void __gcov_module_copychain(gcov_info* chain);
+
+/** Function called by module unloading to move the module's gcov_info
+ *  instances to the global chain.
+ */
+extern "C"
+void __gcov_module_unload(void* unused)
+{
+    __gcov_module_copychain(GCOV_INFO_OBJ());
+}
+    // Register __gcov_module_unload with __cxa_atexit.
+extern void* __dso_handle;
+extern "C" int __cxa_atexit(void(*)(void*),void*,void*);
+int __unused_gcov_cxa_register =
+                    __cxa_atexit(&__gcov_module_unload, NULL, __dso_handle);
+#else
+/** Function called by a module being unloaded (via __gcov_module_unload) to
+ *  copy the module's gcov_info chain into the base gcov_info chain.
+ */
+extern "C"
+void __gcov_module_copychain(gcov_info* chain)
+{
+    while(chain != NULL)
+    {
+        // Copy old info.
+        gcov_info* new_info = new gcov_info;
+        memcpy(new_info, chain, sizeof(gcov_info));
+
+        // Copy old counters.
+        uint64_t* new_counters = new uint64_t[chain->n_counters];
+        memcpy(new_counters, chain->counters,
+               chain->n_counters*sizeof(uint64_t));
+        new_info->counters = new_counters;
+
+        // Atomically push new_info onto the core_gcov_info_head stack.
+        do
+        {
+            new_info->next = GCOV_INFO_OBJ();
+        } while (!__sync_bool_compare_and_swap(&GCOV_INFO_OBJ(),
+                                               new_info->next, new_info));
+
+        // Advance to next info in this modules chain.
+        chain = chain->next;
+    }
+}
+#endif
+
 /** Unneeded function but must be defined to compile.
  *
  *  This function appears to be typically used by libgcov.so when instrumented