SERVER-50476 created gdb_index scons tool to generate gdb_index

2 files changed, 200 insertions, 25 deletions

diff --git a/site_scons/site_tools/gdb_index.py b/site_scons/site_tools/gdb_index.py
new file mode 100644
index 00000000000..5850b8560d3
--- /dev/null
+++ b/site_scons/site_tools/gdb_index.py
@@ -0,0 +1,134 @@
+# Copyright 2020 MongoDB Inc.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+import SCons
+
+
+def _update_builder(env, builder):
+
+    verbose = '' if env.Verbose() else None
+
+    base_action = builder.action
+    if not isinstance(base_action, SCons.Action.ListAction):
+        base_action = SCons.Action.ListAction([base_action])
+
+    # There are cases were a gdb-index file is NOT generated from gdb 'save gdb-index' command,
+    # mostly shim libraries where there is no code in the library, and the following Actions would
+    # then fail. The files are created make sure there is always a file to operate on, if its an
+    # empty file then the following actions are basically NOOP, and its cleaner then writing
+    # conditions into each action.
+
+    # Because this is all taking under one task, the list action will always run all actions if
+    # the target is out of date. So the gdb-index files would always be regenerated, and there is
+    # no value in keeping them around, it will just waste disk space. Therefore they should be
+    # removed as if they never existed from the task. The build system doesn't need to know about
+    # them.
+    if env.get('DWARF_VERSION') <= 4:
+        base_action.list.extend([
+            SCons.Action.Action(
+                'touch ${TARGET}.gdb-index',
+                verbose,
+            ),
+            SCons.Action.Action(
+                '$GDB --batch-silent --quiet --nx --eval-command "save gdb-index ${TARGET.dir}" $TARGET',
+                "$GDB_INDEX_GEN_INDEX_STR",
+            ),
+            SCons.Action.Action(
+                '$OBJCOPY --add-section .gdb_index=${TARGET}.gdb-index --set-section-flags .gdb_index=readonly ${TARGET} ${TARGET}',
+                "$GDB_INDEX_ADD_SECTION_STR",
+            ),
+            SCons.Action.Action(
+                'rm -f ${TARGET}.gdb-index',
+                verbose,
+            ),
+        ])
+    else:
+        base_action.list.extend([
+            SCons.Action.Action(
+                'touch ${TARGET}.debug_names ${TARGET}.debug_str',
+                verbose,
+            ),
+            SCons.Action.Action(
+                '$GDB --batch-silent --quiet --nx --eval-command "save gdb-index -dwarf-5 ${TARGET.dir}" $TARGET',
+                "$GDB_INDEX_GEN_INDEX_STR",
+            ),
+            SCons.Action.Action(
+                '$OBJCOPY --dump-section .debug_str=${TARGET}.debug_str.new $TARGET',
+                verbose,
+            ),
+            SCons.Action.Action(
+                'cat ${TARGET}.debug_str >>${TARGET}.debug_str.new',
+                verbose,
+            ),
+            SCons.Action.Action(
+                '$OBJCOPY --add-section .debug_names=${TARGET}.debug_names --set-section-flags .debug_names=readonly --update-section .debug_str=${TARGET}.debug_str.new ${TARGET} ${TARGET}',
+                "$GDB_INDEX_ADD_SECTION_STR",
+            ),
+            SCons.Action.Action(
+                'rm -f ${TARGET}.debug_names ${TARGET}.debug_str.new ${TARGET}.debug_str',
+                verbose,
+            ),
+        ])
+
+    builder.action = base_action
+
+
+def generate(env):
+    if env.get("OBJCOPY", None) is None:
+        env["OBJCOPY"] = env.WhereIs("objcopy")
+    if env.get("GDB", None) is None:
+        env["GDB"] = env.WhereIs("gdb")
+
+    if not env.Verbose():
+        env.Append(
+            GDB_INDEX_GEN_INDEX_STR="Using $GDB to generate index for $TARGET",
+            GDB_INDEX_ADD_SECTION_STR="Adding index sections into $TARGET",
+        )
+
+    for builder in ["Program", "SharedLibrary", "LoadableModule"]:
+        _update_builder(env, env["BUILDERS"][builder])
+
+
+def exists(env):
+    result = False
+    if env.TargetOSIs("posix"):
+        objcopy = env.get("OBJCOPY", None) or env.WhereIs("objcopy")
+        gdb = env.get("GDB", None) or env.WhereIs("gdb")
+        try:
+            dwarf_version = int(env.get('DWARF_VERSION'))
+        except ValueError:
+            dwarf_version = None
+
+        unset_vars = []
+        if not objcopy:
+            unset_vars += ['OBJCOPY']
+        if not gdb:
+            unset_vars += ['GDB']
+        if not dwarf_version:
+            unset_vars += ['DWARF_VERSION']
+
+        if not unset_vars:
+            print("Enabled generation of gdb index into binaries.")
+            result = True
+        else:
+            print(f"Disabled generation gdb index because {', '.join(unset_vars)} were not set.")
+    return result
diff --git a/site_scons/site_tools/ninja.py b/site_scons/site_tools/ninja.py
index a55205fc612..78c9e87e66a 100644
--- a/site_scons/site_tools/ninja.py
+++ b/site_scons/site_tools/ninja.py
@@ -267,6 +267,35 @@ def generate_depfile(env, node, dependencies):
             f.write(depfile_contents)
 
 
+def _extract_cmdstr_for_list_action(ninja_build_list):
+    cmdline = ""
+    for cmd in ninja_build_list:
+
+        # Occasionally a command line will expand to a
+        # whitespace only string (i.e. '  '). Which is not a
+        # valid command but does not trigger the empty command
+        # condition if not cmdstr. So here we trim the whitespace
+        # to make strings like the above become empty strings and
+        # so they will be skipped.
+        cmdstr = cmd["variables"]["cmd"].strip()
+        if not cmdstr:
+            continue
+
+        # Skip duplicate commands
+        if cmdstr in cmdline:
+            continue
+
+        if cmdline:
+            cmdline += " && "
+
+        cmdline += cmdstr
+
+    # Remove all preceding and proceeding whitespace
+    cmdline = cmdline.strip()
+
+    return cmdline
+
+
 class SConsToNinjaTranslator:
     """Translates SCons Actions into Ninja build objects."""
 
@@ -384,31 +413,8 @@ class SConsToNinjaTranslator:
         all_outputs = list({output for build in results for output in build["outputs"]})
         dependencies = list({dep for build in results for dep in build["implicit"]})
 
-        if results[0]["rule"] == "CMD":
-            cmdline = ""
-            for cmd in results:
-
-                # Occasionally a command line will expand to a
-                # whitespace only string (i.e. '  '). Which is not a
-                # valid command but does not trigger the empty command
-                # condition if not cmdstr. So here we strip preceding
-                # and proceeding whitespace to make strings like the
-                # above become empty strings and so will be skipped.
-                cmdstr = cmd["variables"]["cmd"].strip()
-                if not cmdstr:
-                    continue
-
-                # Skip duplicate commands
-                if cmdstr in cmdline:
-                    continue
-
-                if cmdline:
-                    cmdline += " && "
-
-                cmdline += cmdstr
-
-            # Remove all preceding and proceeding whitespace
-            cmdline = cmdline.strip()
+        if all([result['rule'] == 'CMD' for result in results]):
+            cmdline = _extract_cmdstr_for_list_action(results)
 
             # Make sure we didn't generate an empty cmdline
             if cmdline:
@@ -431,6 +437,34 @@ class SConsToNinjaTranslator:
 
                 return ninja_build
 
+        elif results[0]["rule"] == "LINK" and all(
+            [result['rule'] == 'CMD' for result in results[1:]]):
+            cmdline = _extract_cmdstr_for_list_action(results[1:])
+
+            # Make sure we didn't generate an empty cmdline
+            if cmdline:
+
+                env = node.env if node.env else self.env
+                sources = [get_path(src_file(s)) for s in node.sources]
+
+                ninja_build = results[0]
+
+                ninja_build.update({
+                    "outputs": all_outputs,
+                    "rule": "LINK_CHAINED_CMD",
+                    "implicit": dependencies,
+                })
+
+                ninja_build['variables'].update({
+                    "cmd": cmdline,
+                    "env": get_command_env(env, all_outputs, sources),
+                })
+
+                if node.env and node.env.get("NINJA_POOL", None) is not None:
+                    ninja_build["pool"] = node.env["pool"]
+
+                return ninja_build
+
         elif results[0]["rule"] == "phony":
             return {
                 "outputs": all_outputs,
@@ -535,6 +569,13 @@ class NinjaState:
                 "rspfile_content": "$rspc",
                 "pool": "local_pool",
             },
+            "LINK_CHAINED_CMD": {
+                "command": "$env$LINK @$out.rsp && $cmd",
+                "description": "Linked $out",
+                "rspfile": "$out.rsp",
+                "rspfile_content": "$rspc",
+                "pool": "local_pool",
+            },
             "AR": {
                 "command": "$env$AR @$out.rsp",
                 "description": "Archived $out",