From 99f57feeae5d78e2657f6c4b4de61b81cdad4749 Mon Sep 17 00:00:00 2001
From: Florin Papa <florin.papa@intel.com>
Date: Thu, 8 Feb 2018 16:59:46 -0800
Subject: [PATCH 1/2] Add separate cmake file for setting OS variables

In the Options.cmake file, MAP_TEXT_HUGE_PAGES and ENABLE_FOLLY_SYMBOLIZER
are set depending on the value of the LINUX variable, which is only set in
a file included later - HPHPCompiler.cmake. This causes these 2 variables not
to be visible in third-party modules the first time configure is run
(subsequent times the variables are taken from the cmake cache).

This change fixes this behavior by adding a new cmake file that sets the OS
variables and including it before Options.cmake.
---
 CMake/HPHPCompiler.cmake | 17 -----------------
 CMake/SetOSVars.cmake    | 16 ++++++++++++++++
 CMakeLists.txt           |  1 +
 3 files changed, 17 insertions(+), 17 deletions(-)
 create mode 100644 CMake/SetOSVars.cmake

diff --git a/CMake/HPHPCompiler.cmake b/CMake/HPHPCompiler.cmake
index c1677f9707eb6b..b68d21323f01be 100644
--- a/CMake/HPHPCompiler.cmake
+++ b/CMake/HPHPCompiler.cmake
@@ -1,20 +1,3 @@
-set(FREEBSD FALSE)
-if("${CMAKE_SYSTEM_NAME}" STREQUAL "FreeBSD")
-  set(FREEBSD TRUE)
-endif()
-set(LINUX FALSE)
-if("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux")
-  set(LINUX TRUE)
-endif()
-set(DARWIN FALSE)
-if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
-  set(DARWIN TRUE)
-endif()
-set(WINDOWS FALSE)
-if("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
-  set(WINDOWS TRUE)
-endif()
-
 # Do this until cmake has a define for ARMv8
 INCLUDE(CheckCXXSourceCompiles)
 CHECK_CXX_SOURCE_COMPILES("
diff --git a/CMake/SetOSVars.cmake b/CMake/SetOSVars.cmake
new file mode 100644
index 00000000000000..6bc8383918445b
--- /dev/null
+++ b/CMake/SetOSVars.cmake
@@ -0,0 +1,16 @@
+set(FREEBSD FALSE)
+if("${CMAKE_SYSTEM_NAME}" STREQUAL "FreeBSD")
+  set(FREEBSD TRUE)
+endif()
+set(LINUX FALSE)
+if("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux")
+  set(LINUX TRUE)
+endif()
+set(DARWIN FALSE)
+if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
+  set(DARWIN TRUE)
+endif()
+set(WINDOWS FALSE)
+if("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
+  set(WINDOWS TRUE)
+endif()
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index c5b932f72fb6c1..6679a5ace13e01 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -108,6 +108,7 @@ SET(TP_DIR "${CMAKE_CURRENT_SOURCE_DIR}/third-party")
 SET(TP_BUILD_DIR "${CMAKE_CURRENT_BINARY_DIR}/third-party")
 
 include(MSVCDefaults)
+include(SetOSVars)
 include(Options)
 include(HPHPCompiler)
 include(HPHPFindLibs)

From 01d7370695e7148daa959d7175966a85dcd8f6bd Mon Sep 17 00:00:00 2001
From: Florin Papa <florin.papa@intel.com>
Date: Wed, 7 Feb 2018 10:33:30 -0800
Subject: [PATCH 2/2] Enable folly::Symbolizer for debug symbols

This change depends on https://github.com/hhvm/hhvm-third-party/pull/123,
which enables 2 additional source files to be compiled and adds libunwind as a
dependency for folly. The "-lgcc_s" added before "-lunwind" is used to solve a
linking order issue that causes "_Ux86_64_setcontext" to be called from
libunwind instead of libgcc_s and messes up the signal mask
(more details here http://savannah.nongnu.org/bugs/?48486). The libgcc_s
dependency is already part of HHVM, this change enforces the order in which
the libraries are linked.

By enabling folly::Symbolizer, HHVM will show debug symbols (in stacktraces,
perf, GDB) when huge pages are enabled (default behavior for open
source builds). Also, one nice side-effect is that this change causes HHVM
to show symbols in backtraces (after a crash) for non-huge-pages builds,
which were missing for some reason.
---
 CMake/Options.cmake     | 5 ++++-
 hphp/CMakeLists.txt     | 4 ++++
 hphp/util/portability.h | 1 -
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/CMake/Options.cmake b/CMake/Options.cmake
index b7fd522eb0d6fd..776ff37e9b65b3 100644
--- a/CMake/Options.cmake
+++ b/CMake/Options.cmake
@@ -31,7 +31,10 @@ option(ENABLE_PROXYGEN_SERVER "Build the Proxygen HTTP server" ON)
 option(ENABLE_SPLIT_DWARF "Reduce linker memory usage by putting debugging information into .dwo files" OFF)
 
 IF (LINUX)
-    option(MAP_TEXT_HUGE_PAGES "Remap hot static code onto huge pages" ON)
+  option(MAP_TEXT_HUGE_PAGES "Remap hot static code onto huge pages" ON)
+  IF(${CMAKE_CXX_COMPILER_ID} STREQUAL "GNU")
+    option(ENABLE_FOLLY_SYMBOLIZER "Use folly::Symbolizer to obtain debug symbols when mapping text section onto huge pages" ON)
+  ENDIF()
 ENDIF()
 
 IF (NOT DEFAULT_CONFIG_DIR)
diff --git a/hphp/CMakeLists.txt b/hphp/CMakeLists.txt
index 4d4a8bd0214aeb..5daa62eeefb7bb 100644
--- a/hphp/CMakeLists.txt
+++ b/hphp/CMakeLists.txt
@@ -108,6 +108,10 @@ install(PROGRAMS ${CMAKE_CURRENT_SOURCE_DIR}/tools/oss-repo-mode
 
 add_definitions("-DUSE_CMAKE")
 
+if (ENABLE_FOLLY_SYMBOLIZER)
+    add_definitions(-DUSE_FOLLY_SYMBOLIZER)
+endif()
+
 enable_language(ASM)
 
 link_libraries(folly)
diff --git a/hphp/util/portability.h b/hphp/util/portability.h
index 2e79788e0fb4e2..3c7a9cb23ac5f2 100644
--- a/hphp/util/portability.h
+++ b/hphp/util/portability.h
@@ -231,7 +231,6 @@
 //////////////////////////////////////////////////////////////////////
 
 #if FACEBOOK
-#define USE_FOLLY_SYMBOLIZER 1
 // Linking in libbfd is a gigantic PITA, but if folly symbolizer doesn't
 // work on your platform, you'll need to figure it out.
 #define HAVE_LIBBFD 1