Add Emscripten support to CMakeLists as much as possible

Only need to set Emscripten's toolchain file and all tests and benchmarks work normally.

.github/workflows/tests.yml

@@ -39,20 +39,9 @@ jobs:
             test-amalgamation: true
 
           - os: ubuntu-latest
-            description: "Emscripten"
+            description: "Emscripten 3.1"
             emscripten-version: "3.1.52"
-            # needs:
-            # - use emscripten's cmake toolchain file so cmake uses em++ and such
-            # - must compile with -pthread for C++11 threads to work
-            #
-            # See https://emscripten.org/docs/porting/pthreads.html
-            #
-            # poolSTL test-suite specific options:
-            # - using -sNO_DISABLE_EXCEPTION_CATCHING because some tests throw
-            # - using high -sTOTAL_MEMORY because our benchmarks use large arrays
-            # - disable codecov because emscripten does not support it.
-            # - Consider -DCMAKE_EXE_LINKER_FLAGS="-sPTHREAD_POOL_SIZE=navigator.hardwareConcurrency"
-            cmake-flags: '-DCMAKE_TOOLCHAIN_FILE=$(em-config EMSCRIPTEN_ROOT)/cmake/Modules/Platform/Emscripten.cmake -DCMAKE_CXX_FLAGS="-pthread -sNO_DISABLE_EXCEPTION_CATCHING" -DCMAKE_EXE_LINKER_FLAGS="-sTOTAL_MEMORY=2048MB" -DPOOLSTL_TEST_COVERAGE=OFF'
+            cmake-flags: '-DCMAKE_TOOLCHAIN_FILE=$(em-config EMSCRIPTEN_ROOT)/cmake/Modules/Platform/Emscripten.cmake'
 
           - os: ubuntu-latest
             # default GCC, which has gcov

CMakeLists.txt

@@ -43,6 +43,14 @@ target_compile_features(poolSTL INTERFACE cxx_std_11)
 find_package(Threads)
 target_link_libraries(poolSTL INTERFACE Threads::Threads)
 
+if (EMSCRIPTEN)
+    # Emscripten needs -pthread compiler and linker switch for C++11 threads.
+    # Anything that will link against poolSTL also needs to be compiled with -pthread.
+    add_compile_options("-pthread")
+    target_compile_options(poolSTL INTERFACE "-pthread")
+    target_link_options(poolSTL INTERFACE "-pthread")
+endif()
+
 ###############################################
 
 # Tests

README.md

@@ -145,12 +145,15 @@ std::vector<int> vec = {5, 2, 1, 3, 0, 4};
 std::sort(poolstl::par, vec.begin(), vec.end());
 ```
 
-## Installation
+# Installation
 
 ### Single File
 
-Each [release](https://github.com/alugowski/poolSTL/releases/latest) publishes a single-file amalgamated `poolstl.hpp`. Simply copy this into your project.  
-**Note:** Some compilers (non-Apple Clang, GCC 8 and older) require `-lpthread` to use C++11 threads.
+Each [release](https://github.com/alugowski/poolSTL/releases/latest) publishes a single-file amalgamated `poolstl.hpp`. Simply copy this into your project.
+
+**Build requirements:**
+ - Clang and GCC 8 or older: require `-lpthread` to use C++11 threads.
+ - Emscripten: compile and link with `-pthread` to use C++11 threads. [See docs](https://emscripten.org/docs/porting/pthreads.html).
 
 ### CMake
 

benchmark/CMakeLists.txt

@@ -54,3 +54,11 @@ else()
     # MinGW also requires nothing to compile std::execution::par, but performance appears to be the same as sequential.
     target_compile_definitions(poolstl_bench PUBLIC POOLSTL_BENCH_STD_PAR)
 endif()
+
+if (EMSCRIPTEN)
+    # Benchmark uses large arrays that require more than Emscripten's default 16MB.
+    target_link_options(poolstl_bench PUBLIC "-sTOTAL_MEMORY=2048MB")
+
+    # Recommended by docs, but does not appear to have an effect. Maybe new node.js does not need it?
+    # target_link_options(poolstl_bench PUBLIC "-sPTHREAD_POOL_SIZE=navigator.hardwareConcurrency")
+endif()

tests/CMakeLists.txt

@@ -26,7 +26,9 @@ endif()
 # Code Coverage
 option(POOLSTL_TEST_COVERAGE "Code-coverage" OFF)
 if(POOLSTL_TEST_COVERAGE)
-    if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+    if (EMSCRIPTEN)
+        # Clang's code coverage tools not supported on Emscripten (will produce link error).
+    elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
         add_compile_options("--coverage")
         add_link_options("-lgcov" "--coverage")
     elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
@@ -52,6 +54,14 @@ list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/extras)
 include(CTest)
 include(Catch)
 
+
+if (EMSCRIPTEN)
+    # Includes a test that throws exceptions, which are opt-in on Emscripten.
+    # See https://emscripten.org/docs/porting/exceptions.html
+    add_compile_options("-fexceptions")
+    add_link_options("-fexceptions")
+endif()
+
 # tests compiled with C++14 (Catch2 requires C++14)
 add_executable(poolstl_test poolstl_test.cpp)
 target_link_libraries(poolstl_test PRIVATE Catch2::Catch2WithMain poolSTL::poolSTL)