[OpenMP] [OMPD] [3/6] Implementation of OMPD debugging library - libompd. omp-debug: Implementation of OMPD APIs.

[Vigneshbalu]

Summary

This is part of review: https://reviews.llvm.org/D100181
Implementation of OMPD APIs as specified in the doc OpenMP API specificaion (5 OMPD Interface).

[Vigneshbalu]

Addressed clang-tidy warnings.

[Vigneshbalu]

Rebasing the patch.

[Vigneshbalu]

Rebasing the patch.

[Vigneshbalu]

Gentle Reminder !

[hbae]

openmp/libompd/src/omp-debug.cpp

46

Can we return early here if callback table is invalid?

85

Should this be !*handle?

153

ompd_rc_stale_handle looks more accurate.

177

Comment is incorrect.
Something like IN: thread number for the returned handle should be fine.

225

Comment is incorrect.

617

Comment is incorrect. This is also an input.

[Vigneshbalu]

Addressing the review comments.

[Vigneshbalu]

Resolved review comments.

[Vigneshbalu]

Updating with full context diff.

[Vigneshbalu]

Fixing clang-format warnings

[hbae]

LGTM

openmp/libompd/src/CMakeLists.txt

 #
 #//===----------------------------------------------------------------------===//
 #//
 #// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 #// See https://llvm.org/LICENSE.txt for license information.
 #// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #//
 #//===----------------------------------------------------------------------===//
 #
 
 project (libompd)
 cmake_minimum_required(VERSION 3.13.4)
 
-add_library (ompd SHARED TargetValue.cpp)
+add_library (ompd SHARED TargetValue.cpp omp-debug.cpp)
 
 add_dependencies(ompd omp) # ensure generated import library is created first
 
 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
 
 set(LIBOMPD_LD_STD_FLAGS FALSE CACHE BOOL
   "Use -stdlibc++ instead of -libc++ library for C++ ")
 
#  Find and replace/add libstdc++ to loader flags
    STRING( FIND "${CMAKE_SHARED_LINKER_FLAGS}" "-stdlib=libc++" OUT )
    if("${OUT}" STREQUAL "-1" )   
       set (CMAKE_SHARED_LINKER_FLAGS "-stdlib=libstdc++ ${CMAKE_SHARED_LINKER_FLAGS}")         
    else()
       STRING( REPLACE "-stdlib=libc++" "-stdlib=libstdc++" CMAKE_SHARED_LINKER_FLAGS ${CMAKE_SHARED_LINKER_FLAGS} )
    endif()
 endif()
 
+#TODO: Required temporarily for lib to build as during patch submission.
+#when lld used, it expects every symbol to be defined, whereas a few function defined as a part of the next patch
+string(REPLACE "-Wl,-z,defs" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}")
 include_directories (
         ${CMAKE_CURRENT_SOURCE_DIR}
         ${LIBOMP_INCLUDE_DIR}
         ${LIBOMP_SRC_DIR}
 )
 
 INSTALL( TARGETS ompd
         LIBRARY DESTINATION ${OPENMP_INSTALL_LIBDIR}
         ARCHIVE DESTINATION ${OPENMP_INSTALL_LIBDIR}
         RUNTIME DESTINATION bin )

openmp/libompd/src/omp-debug.h

+/*
+ * omp-debug.h
+ *
+ *  Created on: Jan 14, 2015
+ *      Author: Ignacio Laguna
+ *              Joachim Protze
+ *     Contact: [e-mail]
+ *              [e-mail]
+ */
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SRC_OMP_DEBUG_H_
+#define SRC_OMP_DEBUG_H_
+
+#define OMPD_VERSION 201811
+
+#ifdef __cplusplus
+
+#include <cstdlib>
+
+extern "C" {
+#endif
+
+#define OMPD_IMPLEMENTS_OPENMP 5
+#define OMPD_IMPLEMENTS_OPENMP_SUBVERSION 0
+#define OMPD_TR_VERSION 6
+#define OMPD_TR_SUBVERSION 2
+#define OMPD_DLL_VERSION                                                       \
+  (OMPD_IMPLEMENTS_OPENMP << 24) + (OMPD_IMPLEMENTS_OPENMP_SUBVERSION << 16) + \
+      (OMPD_TR_VERSION << 8) + OMPD_TR_SUBVERSION
+
+#define STR_HELPER(x) #x
+#define STR(x) STR_HELPER(x)
+
+#include "omp-tools.h"
+#include "ompd-types.h"
+
+#ifdef __cplusplus
+}
+#endif
+/******************************************************************************
+ * General helper functions
+ ******************************************************************************/
+ompd_rc_t initTypeSizes(ompd_address_space_context_t *context);
+
+// NOLINTNEXTLINE "Used in below Macro:OMPD_CALLBACK."
+static const ompd_callbacks_t *callbacks = nullptr;
+
+// Invoke callback function and return if it fails
+#define OMPD_CALLBACK(fn, ...)                                                 \
+  do {                                                                         \
+    ompd_rc_t _rc = callbacks->fn(__VA_ARGS__);                                \
+    if (_rc != ompd_rc_ok)                                                     \
+      return _rc;                                                              \
+  } while (0)
+
+// Read the memory contents located at the given symbol
+#define OMPD_GET_VALUE(context, th_context, name, size, buf)                   \
+  do {                                                                         \
+    ompd_address_t _addr;                                                      \
+    OMPD_CALLBACK(symbol_addr_lookup, context, th_context, name, &_addr,       \
+                  NULL);                                                       \
+    OMPD_CALLBACK(read_memory, context, th_context, &_addr, size, buf);        \
+  } while (0)
+
+typedef struct _ompd_aspace_cont ompd_address_space_context_t;
+
+typedef struct _ompd_aspace_handle {
+  ompd_address_space_context_t *context;
+  ompd_device_t kind;
+  uint64_t id;
+} ompd_address_space_handle_t;
+
+typedef struct _ompd_thread_handle {
+  ompd_address_space_handle_t *ah;
+  ompd_thread_context_t *thread_context;
+  ompd_address_t th; /* target handle */
+} ompd_thread_handle_t;
+
+typedef struct _ompd_parallel_handle {
+  ompd_address_space_handle_t *ah;
+  ompd_address_t th;  /* target handle */
+  ompd_address_t lwt; /* lwt handle */
+} ompd_parallel_handle_t;
+
+typedef struct _ompd_task_handle {
+  ompd_address_space_handle_t *ah;
+  ompd_address_t th;  /* target handle */
+  ompd_address_t lwt; /* lwt handle */
+  _ompd_task_handle() {
+    ah = NULL;
+    th.segment = OMPD_SEGMENT_UNSPECIFIED;
+    lwt.segment = OMPD_SEGMENT_UNSPECIFIED;
+    th.address = 0;
+    lwt.address = 0;
+  }
+} ompd_task_handle_t;
+
+void __ompd_init_icvs(const ompd_callbacks_t *table);
+void __ompd_init_states(const ompd_callbacks_t *table);
+
+#endif /* SRC_OMP_DEBUG_H_ */

openmp/libompd/src/omp-debug.cpp

+/*
+ * omp-debug.cpp
+ *
+ *  Created on: Jan 14, 2015
+ *      Author: Ignacio Laguna
+ *              Joachim Protze
+ *     Contact: [e-mail]
+ *              [e-mail]
+ */
+/*******************************************************************************
+ * This implements an OMPD DLL for the LLVM OpenMP runtime library.
+ */
+
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#define NDEBUG 1
+
+#include "omp-debug.h"
+#include "TargetValue.h"
+#include "omp.h"
+#include "ompd-private.h"
+#include <assert.h>
+#include <cstdio>
+#include <inttypes.h>
+#include <pthread.h>
+#include <stdint.h>
+
+ompd_device_type_sizes_t type_sizes;
+uint64_t ompd_state;
+ompd_rc_t ompd_get_num_threads(
+    ompd_parallel_handle_t *parallel_handle, /* IN: OpenMP parallel handle */
+    ompd_word_t *val /* OUT: number of threads */);
+
+/* --- OMPD functions ------------------------------------------------------- */
+
+/* --- Initialization ------------------------------------------------------- */
+
+ompd_rc_t ompd_initialize(ompd_word_t version, const ompd_callbacks_t *table) {
+  ompd_rc_t ret = ompd_rc_ok;
+  ompd_word_t ompd_version;
+
+  if (!table)
+    return ompd_rc_bad_input;
+
+  ompd_get_api_version(&ompd_version);
+  if (version != ompd_version)
+    return ompd_rc_unsupported;
+  callbacks = table;
+  TValue::callbacks = table;
+  __ompd_init_icvs(table);
+  __ompd_init_states(table);
+
+  return ret;
+}
+
+ompd_rc_t ompd_finalize(void) { return ompd_rc_ok; }
+
+ompd_rc_t ompd_process_initialize(
+    ompd_address_space_context_t
+        *context, /* IN: debugger handle for the target */
+    ompd_address_space_handle_t **handle /* OUT: ompd handle for the target */
+) {
+  if (!context)
+    return ompd_rc_bad_input;
+  if (!handle)
+    return ompd_rc_bad_input;
+
+  ompd_rc_t ret = initTypeSizes(context);
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  ret = TValue(context, "ompd_state")
+            .castBase(ompd_type_long_long)
+            .getValue(ompd_state);
+  if (ret != ompd_rc_ok)
+    return ret;
+  ret = callbacks->alloc_memory(sizeof(ompd_address_space_handle_t),
+                                (void **)(handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+  if (!*handle)
+    return ompd_rc_error;
+
+  (*handle)->context = context;
+  (*handle)->kind = OMPD_DEVICE_KIND_HOST;
+
+  return ompd_rc_ok;
+}
+
+ompd_rc_t
+ompd_get_omp_version(ompd_address_space_handle_t
+                         *address_space, /* IN: handle for the address space */
+                     ompd_word_t *version) {
+  if (!address_space)
+    return ompd_rc_stale_handle;
+  if (!version)
+    return ompd_rc_bad_input;
+
+  ompd_address_space_context_t *context = address_space->context;
+  ompd_rc_t ret;
+
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ret = TValue(context, "__kmp_openmp_version")
+            .castBase(ompd_type_int)
+            .getValue(*version);
+  return ret;
+}
+
+ompd_rc_t ompd_get_omp_version_string(
+    ompd_address_space_handle_t
+        *address_space, /* IN: handle for the address space */
+    const char **string) {
+  if (!address_space)
+    return ompd_rc_stale_handle;
+  if (!string)
+    return ompd_rc_bad_input;
+  ompd_address_space_context_t *context = address_space->context;
+  ompd_word_t ver;
+  ompd_rc_t ret;
+  char *omp_version;
+  ret = callbacks->alloc_memory(10, /* max digit can be store on int*/
+                                (void **)&omp_version);
+
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  ret = TValue(context, "__kmp_openmp_version")
+            .castBase(ompd_type_int)
+            .getValue(ver);
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  sprintf(omp_version, "%ld", ver);
+  *string = omp_version;
+  return ret;
+}
+
+ompd_rc_t ompd_rel_address_space_handle(
+    ompd_address_space_handle_t
+        *addr_handle /* IN: handle for the address space */
+) {
+  if (!addr_handle)
+    return ompd_rc_stale_handle;
+
+  ompd_rc_t ret = callbacks->free_memory((void *)(addr_handle));
+  //  delete addr_handle;
+  return ret;
+}
+
+ompd_rc_t ompd_device_initialize(ompd_address_space_handle_t *process_handle,
+                                 ompd_address_space_context_t *device_context,
+                                 ompd_device_t kind, ompd_size_t sizeof_id,
+                                 void *id,
+                                 ompd_address_space_handle_t **device_handle) {
+  if (!device_context)
+    return ompd_rc_bad_input;
+
+  return ompd_rc_unavailable;
+}
+
+/* --- Thread Handles ------------------------------------------------------- */
+
+/* thread_handle is of type (kmp_base_info_t) */
+
+ompd_rc_t ompd_get_thread_in_parallel(
+    ompd_parallel_handle_t *parallel_handle, /* IN: OpenMP parallel handle */
+    int thread_num, /* IN: Thread num, handle of which is to be returned */
+    ompd_thread_handle_t **thread_handle /* OUT: handle */
+) {
+  if (!parallel_handle)
+    return ompd_rc_stale_handle;
+  if (!parallel_handle->ah)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = parallel_handle->ah->context;
+  ompd_rc_t ret;
+
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_word_t team_size_var;
+  ret = ompd_get_num_threads(parallel_handle, &team_size_var);
+  if (ret != ompd_rc_ok)
+    return ret;
+  if (thread_num < 0 || thread_num >= team_size_var)
+    return ompd_rc_bad_input;
+
+  ompd_address_t taddr = {OMPD_SEGMENT_UNSPECIFIED, 0};
+
+  ret = TValue(context, parallel_handle->th) /* t */
+            .cast("kmp_base_team_t", 0)
+            .access("t_threads") /*t.t_threads*/
+            .cast("kmp_info_t", 2)
+            .getArrayElement(thread_num) /*t.t_threads[nth_handle]*/
+            .access("th")                /*t.t_threads[i]->th*/
+            .getAddress(&taddr);
+
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  ret = callbacks->alloc_memory(sizeof(ompd_thread_handle_t),
+                                (void **)(thread_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  (*thread_handle)->th = taddr;
+  (*thread_handle)->ah = parallel_handle->ah;
+  return ret;
+}
+
+ompd_rc_t ompd_rel_thread_handle(
+    ompd_thread_handle_t
+        *thread_handle /* IN: OpenMP thread handle to be released */
+) {
+  if (!thread_handle)
+    return ompd_rc_stale_handle;
+  ompd_rc_t ret = callbacks->free_memory((void *)(thread_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t ompd_thread_handle_compare(ompd_thread_handle_t *thread_handle_1,
+                                     ompd_thread_handle_t *thread_handle_2,
+                                     int *cmp_value) {
+  if (!thread_handle_1)
+    return ompd_rc_stale_handle;
+  if (!thread_handle_2)
+    return ompd_rc_stale_handle;
+  if (!cmp_value)
+    return ompd_rc_bad_input;
+  if (thread_handle_1->ah->kind != thread_handle_2->ah->kind)
+    return ompd_rc_bad_input;
+  *cmp_value = thread_handle_1->th.address - thread_handle_2->th.address;
+
+  return ompd_rc_ok;
+}
+
+/* --- Parallel Region Handles----------------------------------------------- */
+
+/* parallel_handle is of type (kmp_base_team_t)*/
+
+ompd_rc_t ompd_get_curr_parallel_handle(
+    ompd_thread_handle_t *thread_handle,     /* IN: OpenMP thread handle*/
+    ompd_parallel_handle_t **parallel_handle /* OUT: OpenMP parallel handle */
+) {
+  if (!thread_handle)
+    return ompd_rc_stale_handle;
+  if (!thread_handle->ah)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = thread_handle->ah->context;
+  ompd_thread_context_t *thread_context = thread_handle->thread_context;
+  if (!context || !thread_context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_rc_t ret;
+
+  ompd_address_t taddr = {OMPD_SEGMENT_UNSPECIFIED, 0},
+                 lwt = {OMPD_SEGMENT_UNSPECIFIED, 0};
+
+  TValue teamdata = TValue(context, thread_handle->th) /*__kmp_threads[t]->th*/
+                        .cast("kmp_base_info_t")
+                        .access("th_team") /*__kmp_threads[t]->th.th_team*/
+                        .cast("kmp_team_p", 1)
+                        .access("t"); /*__kmp_threads[t]->th.th_team->t*/
+
+  ret = teamdata.getAddress(&taddr);
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  lwt.segment = OMPD_SEGMENT_UNSPECIFIED;
+  ret = teamdata.cast("kmp_base_team_t", 0)
+            .access("ompt_serialized_team_info")
+            .castBase()
+            .getValue(lwt.address);
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  ret = callbacks->alloc_memory(sizeof(ompd_parallel_handle_t),
+                                (void **)(parallel_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  (*parallel_handle)->ah = thread_handle->ah;
+  (*parallel_handle)->th = taddr;
+  (*parallel_handle)->lwt = lwt;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t ompd_get_enclosing_parallel_handle(
+    ompd_parallel_handle_t *parallel_handle, /* IN: OpenMP parallel handle */
+    ompd_parallel_handle_t *
+        *enclosing_parallel_handle /* OUT: OpenMP parallel handle */
+) {
+  if (!parallel_handle)
+    return ompd_rc_stale_handle;
+  if (!parallel_handle->ah)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = parallel_handle->ah->context;
+
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_address_t taddr = parallel_handle->th,
+                 lwt = {OMPD_SEGMENT_UNSPECIFIED, 0};
+  ompd_rc_t ret;
+
+  ret = ompd_rc_stale_handle;
+  TValue lwtValue = TValue(context, parallel_handle->lwt);
+  if (lwtValue.getError() == ompd_rc_ok) // lwt == 0x0
+  {                                      // if we are in lwt, get parent
+    ret = lwtValue.cast("ompt_lw_taskteam_t", 0)
+              .access("parent")
+              .cast("ompt_lw_taskteam_t", 1)
+              .dereference()
+              .getAddress(&lwt);
+  }
+  if (ret != ompd_rc_ok) { // no lwt or parent==0x0
+
+    TValue teamdata =
+        TValue(context, parallel_handle->th) /*__kmp_threads[t]->th*/
+            .cast("kmp_base_team_t", 0)      /*t*/
+            .access("t_parent")              /*t.t_parent*/
+            .cast("kmp_team_p", 1)
+            .access("t"); /*t.t_parent->t*/
+
+    ret = teamdata.getAddress(&taddr);
+    if (ret != ompd_rc_ok)
+      return ret;
+
+    lwt.segment = OMPD_SEGMENT_UNSPECIFIED;
+    ret = teamdata.cast("kmp_base_team_t", 0)
+              .access("ompt_serialized_team_info")
+              .castBase()
+              .getValue(lwt.address);
+    if (ret != ompd_rc_ok)
+      return ret;
+  }
+
+  ret = callbacks->alloc_memory(sizeof(ompd_parallel_handle_t),
+                                (void **)(enclosing_parallel_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+  (*enclosing_parallel_handle)->th = taddr;
+  (*enclosing_parallel_handle)->lwt = lwt;
+  (*enclosing_parallel_handle)->ah = parallel_handle->ah;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t ompd_get_task_parallel_handle(
+    ompd_task_handle_t *task_handle, /* IN: OpenMP task handle */
+    ompd_parallel_handle_t *
+        *task_parallel_handle /* OUT: OpenMP parallel handle */
+) {
+  if (!task_handle)
+    return ompd_rc_stale_handle;
+  if (!task_handle->ah)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = task_handle->ah->context;
+
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_address_t taddr = {OMPD_SEGMENT_UNSPECIFIED, 0};
+
+  ompd_rc_t ret;
+
+  ret = TValue(context, task_handle->th)
+            .cast("kmp_taskdata_t") /*td*/
+            .access("td_team")      /*td.td_team*/
+            .cast("kmp_team_p", 1)
+            .access("t") /*td.td_team->t*/
+            .getAddress(&taddr);
+
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  ret = callbacks->alloc_memory(sizeof(ompd_parallel_handle_t),
+                                (void **)(task_parallel_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  (*task_parallel_handle)->ah = task_handle->ah;
+  (*task_parallel_handle)->lwt = task_handle->lwt;
+  (*task_parallel_handle)->th = taddr;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t ompd_rel_parallel_handle(
+    ompd_parallel_handle_t *parallel_handle /* IN: OpenMP parallel handle */
+) {
+  if (!parallel_handle)
+    return ompd_rc_stale_handle;
+  ompd_rc_t ret = callbacks->free_memory((void *)(parallel_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t
+ompd_parallel_handle_compare(ompd_parallel_handle_t *parallel_handle_1,
+                             ompd_parallel_handle_t *parallel_handle_2,
+                             int *cmp_value) {
+  if (!parallel_handle_1)
+    return ompd_rc_stale_handle;
+  if (!parallel_handle_2)
+    return ompd_rc_stale_handle;
+  if (!cmp_value)
+    return ompd_rc_bad_input;
+  if (parallel_handle_1->ah->kind != parallel_handle_2->ah->kind)
+    return ompd_rc_bad_input;
+  if (parallel_handle_1->ah->kind == OMPD_DEVICE_KIND_HOST) {
+    if (parallel_handle_1->th.address - parallel_handle_2->th.address)
+      *cmp_value =
+          parallel_handle_1->th.address - parallel_handle_2->th.address;
+    else
+      *cmp_value =
+          parallel_handle_1->lwt.address - parallel_handle_2->lwt.address;
+  } else {
+    *cmp_value = parallel_handle_1->th.address - parallel_handle_2->th.address;
+  }
+  return ompd_rc_ok;
+}
+
+/* ------- Task Handles ----------------------------------------------------- */
+
+/* task_handle is of type (kmp_taskdata_t) */
+
+ompd_rc_t ompd_get_curr_task_handle(
+    ompd_thread_handle_t *thread_handle, /* IN: OpenMP thread handle*/
+    ompd_task_handle_t **task_handle     /* OUT: OpenMP task handle */
+) {
+  if (!thread_handle)
+    return ompd_rc_stale_handle;
+  if (!thread_handle->ah)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = thread_handle->ah->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_address_t taddr = {OMPD_SEGMENT_UNSPECIFIED, 0},
+                 lwt = {OMPD_SEGMENT_UNSPECIFIED, 0};
+  ompd_rc_t ret = ompd_rc_ok;
+
+  lwt.segment = OMPD_SEGMENT_UNSPECIFIED;
+
+  TValue taskdata =
+      TValue(context, thread_handle->th) /*__kmp_threads[t]->th*/
+          .cast("kmp_base_info_t")
+          .access("th_current_task") /*__kmp_threads[t]->th.th_current_task*/
+          .cast("kmp_taskdata_t", 1);
+
+  ret = taskdata.dereference().getAddress(&taddr);
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  ret = taskdata
+            .access("td_team") /*td.td_team*/
+            .cast("kmp_team_p", 1)
+            .access("t") /*td.td_team->t*/
+            .cast("kmp_base_team_t", 0)
+            .access("ompt_serialized_team_info")
+            .castBase()
+            .getValue(lwt.address);
+
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  ret = callbacks->alloc_memory(sizeof(ompd_task_handle_t),
+                                (void **)(task_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  (*task_handle)->th = taddr;
+  (*task_handle)->lwt = lwt;
+  (*task_handle)->ah = thread_handle->ah;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t ompd_get_generating_task_handle(
+    ompd_task_handle_t *task_handle,        /* IN: OpenMP task handle */
+    ompd_task_handle_t **parent_task_handle /* OUT: OpenMP task handle */
+) {
+  if (!task_handle)
+    return ompd_rc_stale_handle;
+  if (!task_handle->ah)
+    return ompd_rc_stale_handle;
+
+  ompd_address_space_context_t *context = task_handle->ah->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_address_t taddr = task_handle->th, lwt = {OMPD_SEGMENT_UNSPECIFIED, 0};
+
+  ompd_rc_t ret = ompd_rc_stale_handle;
+  TValue lwtValue = TValue(context, task_handle->lwt);
+  if (lwtValue.getError() == ompd_rc_ok) // lwt == 0x0
+  {                                      // if we are in lwt, get parent
+    ret = lwtValue.cast("ompt_lw_taskteam_t", 0)
+              .access("parent")
+              .cast("ompt_lw_taskteam_t", 1)
+              .dereference()
+              .getAddress(&lwt);
+  }
+  if (ret != ompd_rc_ok) { // no lwt or parent==0x0
+
+    TValue taskdata = TValue(context, task_handle->th) /*__kmp_threads[t]->th*/
+                          .cast("kmp_taskdata_t")      /*td*/
+                          .access("td_parent")         /*td->td_parent*/
+                          .cast("kmp_taskdata_t", 1);
+
+    ret = taskdata.dereference().getAddress(&taddr);
+    if (ret != ompd_rc_ok)
+      return ret;
+
+    lwt.segment = OMPD_SEGMENT_UNSPECIFIED;
+    ret = taskdata
+              .access("td_team") /*td.td_team*/
+              .cast("kmp_team_p", 1)
+              .access("t") /*td.td_team->t*/
+              .cast("kmp_base_team_t", 0)
+              .access("ompt_serialized_team_info")
+              .castBase()
+              .getValue(lwt.address);
+    if (ret != ompd_rc_ok)
+      return ret;
+  }
+
+  ret = callbacks->alloc_memory(sizeof(ompd_task_handle_t),
+                                (void **)(parent_task_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  (*parent_task_handle)->th = taddr;
+  (*parent_task_handle)->lwt = lwt;
+  (*parent_task_handle)->ah = task_handle->ah;
+  return ret;
+}
+
+ompd_rc_t ompd_get_scheduling_task_handle(
+    ompd_task_handle_t *task_handle,        /* IN: OpenMP task handle */
+    ompd_task_handle_t **parent_task_handle /* OUT: OpenMP task handle */
+) {
+  if (!task_handle)
+    return ompd_rc_stale_handle;
+  if (!task_handle->ah)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = task_handle->ah->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_address_t taddr = {OMPD_SEGMENT_UNSPECIFIED, 0};
+  ompd_rc_t ret;
+
+  ret = TValue(context, task_handle->th)
+            .cast("kmp_taskdata_t")   /*td*/
+            .access("ompt_task_info") // td->ompt_task_info
+            .cast("ompt_task_info_t")
+            .access("scheduling_parent") // td->ompd_task_info.scheduling_parent
+            .cast("kmp_taskdata_t", 1)
+            .castBase()
+            .getValue(taddr.address);
+  if (taddr.address == 0) {
+    return ompd_rc_unavailable;
+  }
+
+  if (ret != ompd_rc_ok)
+    return ret;
+  ret = callbacks->alloc_memory(sizeof(ompd_task_handle_t),
+                                (void **)(parent_task_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  (*parent_task_handle)->th = taddr;
+  (*parent_task_handle)->lwt = {OMPD_SEGMENT_UNSPECIFIED, 0};
+  (*parent_task_handle)->ah = task_handle->ah;
+  return ret;
+}
+
+ompd_rc_t ompd_get_task_in_parallel(
+    ompd_parallel_handle_t *parallel_handle, /* IN: OpenMP parallel handle */
+    int thread_num, /* IN: thread num of implicit task of team */
+    ompd_task_handle_t **task_handle /* OUT: OpenMP task handle */
+) {
+  if (!parallel_handle)
+    return ompd_rc_stale_handle;
+  if (!parallel_handle->ah)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = parallel_handle->ah->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_rc_t ret;
+  ompd_word_t team_size_var;
+  ret = ompd_get_num_threads(parallel_handle, &team_size_var);
+  if (ret != ompd_rc_ok)
+    return ret;
+  if (thread_num < 0 || thread_num >= team_size_var)
+    return ompd_rc_bad_input;
+
+  ompd_address_t taddr = {OMPD_SEGMENT_UNSPECIFIED, 0};
+
+  ret = TValue(context, parallel_handle->th) /* t */
+            .cast("kmp_base_team_t", 0)
+            .access("t_implicit_task_taskdata") /*t.t_implicit_task_taskdata*/
+            .cast("kmp_taskdata_t", 1)
+            .getArrayElement(
+                thread_num) /*t.t_implicit_task_taskdata[nth_handle]*/
+            .getAddress(&taddr);
+
+  if (ret != ompd_rc_ok)
+    return ret;
+  ret = callbacks->alloc_memory(sizeof(ompd_task_handle_t),
+                                (void **)(task_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  (*task_handle)->th = taddr;
+  (*task_handle)->ah = parallel_handle->ah;
+  (*task_handle)->lwt = {OMPD_SEGMENT_UNSPECIFIED, 0};
+  return ret;
+}
+
+ompd_rc_t ompd_rel_task_handle(
+    ompd_task_handle_t *task_handle /* IN: OpenMP task handle */
+) {
+  if (!task_handle)
+    return ompd_rc_stale_handle;
+  ompd_rc_t ret = callbacks->free_memory((void *)(task_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t ompd_task_handle_compare(ompd_task_handle_t *task_handle_1,
+                                   ompd_task_handle_t *task_handle_2,
+                                   int *cmp_value) {
+  if (!task_handle_1)
+    return ompd_rc_stale_handle;
+  if (!task_handle_2)
+    return ompd_rc_stale_handle;
+  if (!cmp_value)
+    return ompd_rc_bad_input;
+  if (task_handle_1->ah->kind != task_handle_2->ah->kind)
+    return ompd_rc_bad_input;
+  if (task_handle_1->th.address - task_handle_2->th.address)
+    *cmp_value = task_handle_1->th.address - task_handle_2->th.address;
+  else
+    *cmp_value = task_handle_1->lwt.address - task_handle_2->lwt.address;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t ompd_get_thread_handle(
+    ompd_address_space_handle_t *handle, /* IN: handle for the address space */
+    ompd_thread_id_t kind, ompd_size_t sizeof_thread_id, const void *thread_id,
+    ompd_thread_handle_t **thread_handle) {
+  if (!handle)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = handle->context;
+  ompd_rc_t ret;
+
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+  ompd_thread_context_t *tcontext;
+  ret = callbacks->get_thread_context_for_thread_id(
+      context, kind, sizeof_thread_id, thread_id, &tcontext);
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  int tId;
+
+  ret = TValue(context, tcontext, "__kmp_gtid")
+            .castBase("__kmp_gtid")
+            .getValue(tId);
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  if (tId < 0) // thread is no omp worker
+    return ompd_rc_unavailable;
+
+  TValue th = TValue(context, "__kmp_threads") // __kmp_threads
+                  .cast("kmp_info_t", 2)
+                  .getArrayElement(tId) /*__kmp_threads[t]*/
+                  .access("th");        /*__kmp_threads[t]->th*/
+
+  ompd_address_t taddr = {OMPD_SEGMENT_UNSPECIFIED, 0};
+  ret = th.getAddress(&taddr);
+  if (ret != ompd_rc_ok)
+    return ret;
+  ret = callbacks->alloc_memory(sizeof(ompd_thread_handle_t),
+                                (void **)(thread_handle));
+  if (ret != ompd_rc_ok)
+    return ret;
+  (*thread_handle)->ah = handle;
+  (*thread_handle)->th = taddr;
+
+#ifndef NDEBUG
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  pthread_t oshandle;
+  TBaseValue ds_handle =
+      th.cast("kmp_base_info_t")
+          .access("th_info") /*__kmp_threads[t]->th.th_info*/
+          .cast("kmp_desc_t")
+          .access("ds") /*__kmp_threads[t]->th.th_info.ds*/
+          .cast("kmp_desc_base_t")
+          .access("ds_thread") /*__kmp_threads[t]->th.th_info.ds.ds_thread*/
+          .castBase();
+
+  assert(ompd_rc_ok == ds_handle.getValue(oshandle) &&
+         oshandle == *(pthread_t *)(thread_id) &&
+         "Callback table not initialized!");
+#endif
+
+  (*thread_handle)->thread_context = tcontext;
+  return ret;
+}
+
+ompd_rc_t ompd_get_thread_id(
+    ompd_thread_handle_t *thread_handle, /* IN: OpenMP thread handle*/
+    ompd_thread_id_t kind, ompd_size_t sizeof_thread_id, void *thread_id) {
+  if (kind != OMPD_THREAD_ID_PTHREAD)
+    return ompd_rc_unsupported;
+  if (!thread_id)
+    return ompd_rc_bad_input;
+  if (!thread_handle)
+    return ompd_rc_stale_handle;
+  if (!thread_handle->ah)
+    return ompd_rc_stale_handle;
+  ompd_address_space_context_t *context = thread_handle->ah->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+  ompd_rc_t ret;
+
+  ompd_size_t size;
+  ret = tf.getType(context, "kmp_thread_t").getSize(&size);
+  if (ret != ompd_rc_ok)
+    return ret;
+  if (sizeof_thread_id != size)
+    return ompd_rc_bad_input;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ret = TValue(context, thread_handle->th) /*__kmp_threads[t]->th*/
+            .cast("kmp_base_info_t")
+            .access("th_info") /*__kmp_threads[t]->th.th_info*/
+            .cast("kmp_desc_t")
+            .access("ds") /*__kmp_threads[t]->th.th_info.ds*/
+            .cast("kmp_desc_base_t")
+            .access("ds_thread") /*__kmp_threads[t]->th.th_info.ds.ds_thread*/
+            .cast("kmp_thread_t")
+            .getRawValue(thread_id, 1);
+
+  return ret;
+}
+
+/* --- OMPT Thread State Inquiry Analogue ----------------------------------- */
+
+ompd_rc_t ompd_get_state(
+    ompd_thread_handle_t *thread_handle, /* IN: OpenMP thread handle*/
+    ompd_word_t *state,                  /* OUT: State of this thread */
+    ompd_wait_id_t *wait_id              /* OUT: Wait ID */
+) {
+  if (!thread_handle)
+    return ompd_rc_stale_handle;
+  if (!thread_handle->ah)
+    return ompd_rc_stale_handle;
+  if (!state)
+    return ompd_rc_bad_input;
+  ompd_address_space_context_t *context = thread_handle->ah->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+  if (!ompd_state)
+    return ompd_rc_needs_state_tracking;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+  ompd_rc_t ret;
+
+  TValue ompt_thread_info =
+      TValue(context, thread_handle->th) /*__kmp_threads[t]->th*/
+          .cast("kmp_base_info_t")
+          .access("ompt_thread_info") /*__kmp_threads[t]->th.ompt_thread_info*/
+          .cast("ompt_thread_info_t");
+  if (ompt_thread_info.gotError())
+    return ompt_thread_info.getError();
+  ret = ompt_thread_info
+            .access("state") /*__kmp_threads[t]->th.ompt_thread_info.state*/
+            .castBase()
+            .getValue(*state);
+  if (ret != ompd_rc_ok)
+    return ret;
+  if (wait_id)
+    ret = ompt_thread_info
+              .access("wait_id") /*__kmp_threads[t]->th.ompt_thread_info.state*/
+              .castBase()
+              .getValue(*wait_id);
+
+  return ret;
+}
+
+/* ---  Task Inquiry -------------------------------------------------------- */
+
+/* ---  Task Settings ------------------------------------------------------- */
+
+/* ---  OMPT Task Inquiry Analogues ----------------------------------------- */
+
+ompd_rc_t
+ompd_get_task_frame(ompd_task_handle_t *task_handle, /* IN: OpenMP task handle*/
+                    ompd_frame_info_t *exit_frame,
+                    ompd_frame_info_t *enter_frame) {
+  if (!task_handle)
+    return ompd_rc_stale_handle;
+  if (!task_handle->ah)
+    return ompd_rc_stale_handle;
+  if (!exit_frame || !enter_frame)
+    return ompd_rc_bad_input;
+  ompd_address_space_context_t *context = task_handle->ah->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+  if (!ompd_state)
+    return ompd_rc_needs_state_tracking;
+
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_rc_t ret;
+
+  TValue taskInfo;
+  if (task_handle->lwt.address != 0)
+    taskInfo =
+        TValue(context, task_handle->lwt).cast("ompt_lw_taskteam_t", 0); /*lwt*/
+  else
+    taskInfo = TValue(context, task_handle->th).cast("kmp_taskdata_t", 0); /*t*/
+  TValue frame = taskInfo
+                     .access("ompt_task_info") // td->ompt_task_info
+                     .cast("ompt_task_info_t")
+                     .access("frame") // td->ompd_task_info.frame
+                     .cast("ompt_frame_t", 0);
+  enter_frame->frame_address.segment = OMPD_SEGMENT_UNSPECIFIED;
+  ret = frame
+            .access("enter_frame") // td->ompt_task_info.frame.enter_frame
+            .castBase()
+            .getValue(enter_frame->frame_address.address);
+
+  if (ret != ompd_rc_ok)
+    return ret;
+
+  exit_frame->frame_address.segment = OMPD_SEGMENT_UNSPECIFIED;
+  ret = frame
+            .access("exit_frame") // td->ompt_task_info.frame.exit_frame
+            .castBase()
+            .getValue(exit_frame->frame_address.address);
+
+  return ret;
+}
+
+ompd_rc_t ompd_get_task_function(
+    ompd_task_handle_t *task_handle, /* IN: OpenMP task handle */
+    ompd_address_t *task_addr /* OUT: first instruction in the task region */
+) {
+  if (!task_handle)
+    return ompd_rc_stale_handle;
+  if (!task_handle->ah)
+    return ompd_rc_stale_handle;
+  if (!task_addr)
+    return ompd_rc_bad_input;
+  ompd_address_space_context_t *context = task_handle->ah->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+  if (!ompd_state)
+    return ompd_rc_needs_state_tracking;
+  if (!callbacks) {
+    return ompd_rc_callback_error;
+  }
+
+  ompd_rc_t ret;
+
+  task_addr->segment = OMPD_SEGMENT_UNSPECIFIED;
+  TValue taskInfo;
+  if (task_handle->lwt.address != 0)
+    return ompd_rc_bad_input; // We need to decide what we do here.
+  else {
+    ompd_word_t val;
+    ret = TValue(context, task_handle->th)
+              .cast("kmp_taskdata_t") // td
+              .access("td_flags")     // td->td_flags
+              .cast("kmp_tasking_flags_t")
+              .check("tasktype", &val); // td->td_flags.tasktype
+
+    if (ret != ompd_rc_ok)
+      return ret;
+
+    if (val == 1) { // tasktype: explicit = 1, implicit = 0
+
+      ret = TValue(context, task_handle->th)
+                .cast("kmp_taskdata_t", 0) /*t*/
+                .getArrayElement(
+                    1) /* see kmp.h: #define KMP_TASKDATA_TO_TASK(taskdata)
+                          (kmp_task_t *)(taskdata + 1) */
+                .cast("kmp_task_t", 0) /* (kmp_task_t *) */
+                .access("routine")     /*td->ompt_task_info*/
+                .castBase()
+                .getValue(task_addr->address);
+
+    } else {
+
+      ret = TValue(context, task_handle->th)
+                .cast("kmp_taskdata_t") /*td*/
+                .access("td_team")      /*td.td_team*/
+                .cast("kmp_team_p", 1)
+                .access("t") /*td.td_team->t*/
+                .cast("kmp_base_team_t", 0)
+                .access("t_pkfn") /*td.td_team->t.t_pkfn*/
+                .castBase()
+                .getValue(task_addr->address);
+    }
+  }
+
+  return ret;
+}
+
+/* ------- OMPD Version and Compatibility Information ----------------------- */
+
+ompd_rc_t ompd_get_api_version(ompd_word_t *version) {
+  if (!version)
+    return ompd_rc_bad_input;
+
+  *version = OMPD_VERSION;
+  return ompd_rc_ok;
+}
+
+ompd_rc_t
+ompd_get_version_string(const char **string /* OUT: OMPD version string */
+) {
+  if (!string)
+    return ompd_rc_bad_input;
+
+  static const char version_string[] =
+      "LLVM OpenMP " STR(OMPD_IMPLEMENTS_OPENMP) "." STR(
+          OMPD_IMPLEMENTS_OPENMP_SUBVERSION) " Debugging Library implmenting "
+                                             "TR " STR(OMPD_TR_VERSION) "" STR(
+                                                 OMPD_TR_SUBVERSION);
+  *string = version_string;
+  return ompd_rc_ok;
+}
+
+/* ------ Display Control Variables ----------------------------------------- */
+
+ompd_rc_t ompd_get_display_control_vars(ompd_address_space_handle_t *handle,
+                                        const char *const **control_vars) {
+  if (!handle)
+    return ompd_rc_stale_handle;
+  if (!control_vars)
+    return ompd_rc_bad_input;
+
+  ompd_address_space_context_t *context = handle->context;
+  if (!context)
+    return ompd_rc_stale_handle;
+
+  // runtime keeps a full dump of OMP/KMP definitions in this format
+  // <var1 name>=<var1 value>\n<var2 name>=<var2 value>\n...
+  ompd_address_t block_addr = {ompd_segment_none, 0};
+  OMPD_GET_VALUE(context, NULL, "ompd_env_block", type_sizes.sizeof_pointer,
+                 &block_addr.address);
+
+  // query size of the block
+  ompd_size_t block_size;
+  OMPD_GET_VALUE(context, NULL, "ompd_env_block_size", sizeof(ompd_size_t),
+                 &block_size);
+
+  // copy raw data from the address space
+  char *block;
+  OMPD_CALLBACK(alloc_memory, block_size, (void **)&block);
+  OMPD_CALLBACK(read_memory, context, NULL, &block_addr, block_size, block);
+
+  // count number of items, replace new line to zero.
+  int block_items = 1; // also count the last "NULL" item
+  for (ompd_size_t i = 0; i < block_size; i++) {
+    if (block[i] == '\n') {
+      block_items++;
+      block[i] = '\0';
+    }
+  }
+
+  // create vector of char*
+  const char **ctl_vars;
+  OMPD_CALLBACK(alloc_memory, block_items * sizeof(char *),
+                (void **)(&ctl_vars));
+  char *pos = block;
+  ctl_vars[0] = block;
+
+  // ctl_vars[0] points to the entire block, ctl_vars[1]... points to the
+  // smaller subsets of the block, and ctl_vars[block_items-2] points to the
+  // last string in the block.
+  for (int i = 1; i < block_items - 1; i++) {
+    while (*pos++ != '\0')
+      ;
+    if (pos > block + block_size)
+      return ompd_rc_error;
+    ctl_vars[i] = pos;
+  }
+  // last item must be NULL
+  ctl_vars[block_items - 1] = NULL;
+
+  *control_vars = ctl_vars;
+
+  return ompd_rc_ok;
+}
+
+ompd_rc_t ompd_rel_display_control_vars(const char *const **control_vars) {
+  if (!control_vars)
+    return ompd_rc_bad_input;
+
+  char **ctl_vars = const_cast<char **>(*control_vars);
+
+  // remove the raw block first
+  OMPD_CALLBACK(free_memory, (void *)ctl_vars[0]);
+  // remove the vector
+  OMPD_CALLBACK(free_memory, (void *)ctl_vars);
+
+  return ompd_rc_ok;
+}
+
+/* --- Helper functions ----------------------------------------------------- */
+
+ompd_rc_t initTypeSizes(ompd_address_space_context_t *context) {
+  static int inited = 0;
+  static ompd_rc_t ret;
+  if (inited)
+    return ret;
+  ret = callbacks->sizeof_type(context, &type_sizes);
+  if (ret != ompd_rc_ok)
+    return ret;
+  if (!(type_sizes.sizeof_pointer > 0))
+    return ompd_rc_error;
+  ret = callbacks->sizeof_type(context, &TValue::type_sizes);
+  if (ret != ompd_rc_ok)
+    return ret;
+  inited = 1;
+  return ret;
+}