[arrow] branch master updated: ARROW-4197: [C++] Better Emscripten support

[we...@apache.org]

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wesm pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/arrow.git


The following commit(s) were added to refs/heads/master by this push:
     new a80c27e  ARROW-4197: [C++] Better Emscripten support
a80c27e is described below

commit a80c27e46814ded00216cc48f83e3fedbfb9cf4f
Author: Tim Paine <t....@gmail.com>
AuthorDate: Wed Jan 9 17:34:53 2019 -0600

    ARROW-4197: [C++] Better Emscripten support
    
    A few changes for better compatibility with the Emscripten compiler for WebAssembly
    
    - expose the `-ggdb` flag as an option (unsupported by emscripten)
    - the `-undefined dynamic_lookup` flag should be set on apple, but not when using emscripten
    - allow for `backtrace` to be turned off even if found (no `execinfo.h` available, from `util/logging.cc`)
    
    Author: Tim Paine <t....@gmail.com>
    
    Closes #3350 from timkpaine/emscripten and squashes the following commits:
    
    e3661ff52 <Tim Paine> restore default ggdb behavior, use better environment variable to detect emscripten and add a comment explaining this
    a0e91a77c <Tim Paine> expose backtrace at top level, re-add -g, make backtrace private scope again
    b8f0c8068 <Tim Paine> Merge branch 'master' into emscripten
    5308f6b49 <Tim Paine> fix for emscripten
---
 cpp/CMakeLists.txt                    |  8 ++++++++
 cpp/cmake_modules/BuildUtils.cmake    |  5 ++++-
 cpp/cmake_modules/SetupCxxFlags.cmake | 16 ++++++++++++----
 cpp/src/arrow/CMakeLists.txt          |  2 +-
 4 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
index 3d2b698..4232af3 100644
--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -170,6 +170,10 @@ static|shared (default shared)")
     "If off, 'quiet' flags will be passed to linting tools"
     OFF)
 
+  option(ARROW_GGDB_DEBUG
+    "Pass -ggdb flag to debug builds"
+    ON)
+
   #----------------------------------------------------------------------
   # Project components to enable / disable building
 
@@ -249,6 +253,10 @@ Note that this requires linking Boost statically"
     "Rely on Protocol Buffers shared libraries where relevant"
     OFF)
 
+  option(ARROW_WITH_BACKTRACE
+    "Build with backtrace support"
+    ON)
+
   option(ARROW_USE_GLOG
     "Build libraries with glog support for pluggable logging"
     ON)
diff --git a/cpp/cmake_modules/BuildUtils.cmake b/cpp/cmake_modules/BuildUtils.cmake
index 77db28e..cf2145b 100644
--- a/cpp/cmake_modules/BuildUtils.cmake
+++ b/cpp/cmake_modules/BuildUtils.cmake
@@ -182,11 +182,14 @@ function(ADD_ARROW_LIB LIB_NAME)
         ${ARG_PRIVATE_INCLUDES})
     endif()
 
-    if(APPLE)
+    if(APPLE AND NOT DEFINED $ENV{EMSCRIPTEN})
       # On OS X, you can avoid linking at library load time and instead
       # expecting that the symbols have been loaded separately. This happens
       # with libpython* where there can be conflicts between system Python and
       # the Python from a thirdparty distribution
+      # 
+      # When running with the Emscripten Compiler, we need not worry about
+      # python, and the Emscripten Compiler does not support this option.
       set(ARG_SHARED_LINK_FLAGS
         "-undefined dynamic_lookup ${ARG_SHARED_LINK_FLAGS}")
     endif()
diff --git a/cpp/cmake_modules/SetupCxxFlags.cmake b/cpp/cmake_modules/SetupCxxFlags.cmake
index 1160835..796a68d 100644
--- a/cpp/cmake_modules/SetupCxxFlags.cmake
+++ b/cpp/cmake_modules/SetupCxxFlags.cmake
@@ -340,11 +340,19 @@ endif()
 #   Debug symbols are stripped for reduced binary size. Add
 #   -DARROW_CXXFLAGS="-g" to add them
 if (NOT MSVC)
-  set(C_FLAGS_DEBUG "-ggdb -O0")
-  set(C_FLAGS_FASTDEBUG "-ggdb -O1")
+  if(ARROW_GGDB_DEBUG)
+    set(C_FLAGS_DEBUG "-ggdb -O0")
+    set(C_FLAGS_FASTDEBUG "-ggdb -O1")
+    set(CXX_FLAGS_DEBUG "-ggdb -O0")
+    set(CXX_FLAGS_FASTDEBUG "-ggdb -O1")
+  else()
+    set(C_FLAGS_DEBUG "-g -O0")
+    set(C_FLAGS_FASTDEBUG "-g -O1")
+    set(CXX_FLAGS_DEBUG "-g -O0")
+    set(CXX_FLAGS_FASTDEBUG "-g -O1")
+  endif()
+
   set(C_FLAGS_RELEASE "-O3 -DNDEBUG")
-  set(CXX_FLAGS_DEBUG "-ggdb -O0")
-  set(CXX_FLAGS_FASTDEBUG "-ggdb -O1")
   set(CXX_FLAGS_RELEASE "-O3 -DNDEBUG")
 endif()
 
diff --git a/cpp/src/arrow/CMakeLists.txt b/cpp/src/arrow/CMakeLists.txt
index 91bdce2..59f0357 100644
--- a/cpp/src/arrow/CMakeLists.txt
+++ b/cpp/src/arrow/CMakeLists.txt
@@ -257,7 +257,7 @@ find_package(Backtrace)
 foreach(LIB_TARGET ${ARROW_LIBRARIES})
   target_compile_definitions(${LIB_TARGET}
     PRIVATE ARROW_EXPORTING)
-  if (Backtrace_FOUND)
+  if (Backtrace_FOUND AND ARROW_WITH_BACKTRACE)
     target_compile_definitions(${LIB_TARGET}
       PRIVATE ARROW_WITH_BACKTRACE)
   endif()