Added threads subsetting in emcc compiler model

conan/internal/default_settings.py

@@ -168,6 +168,7 @@
         # There is no ABI compatibility guarantee between versions
         version: [ANY]
         libcxx: [null, libstdc++, libstdc++11, libc++]
+        threads: [null, posix, wasm_workers]
         cppstd: [null, 98, gnu98, 11, gnu11, 14, gnu14, 17, gnu17, 20, gnu20, 23, gnu23, 26, gnu26]
         cstd: [null, 99, gnu99, 11, gnu11, 17, gnu17, 23, gnu23]
 

conan/tools/build/flags.py

@@ -195,6 +195,18 @@ def build_type_flags(conanfile):
             return flags
     return []
 
+def threads_flag(conanfile):
+    """
+    returns flags specific to the threading model used by the compiler
+    """
+    compiler = conanfile.settings.get_safe("compiler")
+    threads = conanfile.settings.get_safe("compiler.threads")
+    if compiler == "emcc":
+        if threads == "posix":
+            return "-pthread"
+        elif threads == "wasm_workers":
+            return "-sWASM_WORKERS=1"
+    return ""
 
 def llvm_clang_front(conanfile):
     # Only Windows clang with MSVC backend (LLVM/Clang, not MSYS2 clang)

conan/tools/cmake/toolchain/blocks.py

@@ -10,7 +10,7 @@
 from conan.tools.android.utils import android_abi
 from conan.tools.apple.apple import is_apple_os, to_apple_arch
 from conan.tools.build import build_jobs
-from conan.tools.build.flags import architecture_flag, architecture_link_flag, libcxx_flags
+from conan.tools.build.flags import architecture_flag, architecture_link_flag, libcxx_flags, threads_flag
 from conan.tools.build.cross_building import cross_building
 from conan.tools.cmake.toolchain import CONAN_TOOLCHAIN_FILENAME
 from conan.tools.cmake.utils import is_multi_configuration
@@ -259,6 +259,21 @@ def context(self):
             return
         return {"arch_flag": arch_flag, "arch_link_flag": arch_link_flag}
 
+class ThreadsBlock(Block):
+    template = textwrap.dedent("""\
+        # Define C++ flags, C flags and linker flags from 'compiler.threads'
+        message(STATUS "Conan toolchain: Defining threads flag: {{ threads_flag }}")
+        string(APPEND CONAN_CXX_FLAGS " {{ threads_flag }}")
+        string(APPEND CONAN_C_FLAGS " {{ threads_flag }}")
+        string(APPEND CONAN_SHARED_LINKER_FLAGS " {{ threads_flag }}")
+        string(APPEND CONAN_EXE_LINKER_FLAGS " {{ threads_flag }}")
+        """)
+
+    def context(self):
+        flags = threads_flag(self._conanfile)
+        if not flags:
+            return
+        return {"threads_flag": flags}
 
 class LinkerScriptsBlock(Block):
     template = textwrap.dedent("""\

conan/tools/cmake/toolchain/toolchain.py

@@ -9,7 +9,7 @@
 from conan.tools.build import use_win_mingw
 from conan.tools.cmake.presets import write_cmake_presets
 from conan.tools.cmake.toolchain import CONAN_TOOLCHAIN_FILENAME
-from conan.tools.cmake.toolchain.blocks import ExtraVariablesBlock, ToolchainBlocks, UserToolchain, \
+from conan.tools.cmake.toolchain.blocks import ExtraVariablesBlock, ThreadsBlock, ToolchainBlocks, UserToolchain, \
     GenericSystemBlock, \
     AndroidSystemBlock, AppleSystemBlock, FPicBlock, ArchitectureBlock, GLibCXXBlock, VSRuntimeBlock, \
     CppStdBlock, ParallelBlock, CMakeFlagsInitBlock, TryCompileBlock, FindFiles, PkgConfigBlock, \
@@ -103,6 +103,7 @@ def __init__(self, conanfile, generator=None):
                                        ("apple_system", AppleSystemBlock),
                                        ("fpic", FPicBlock),
                                        ("arch_flags", ArchitectureBlock),
+                                       ("threads_flags", ThreadsBlock),
                                        ("linker_scripts", LinkerScriptsBlock),
                                        ("libcxx", GLibCXXBlock),
                                        ("vs_runtime", VSRuntimeBlock),

conan/tools/gnu/autotoolstoolchain.py

@@ -7,7 +7,7 @@
 from conan.tools.build import cmd_args_to_string, save_toolchain_args
 from conan.tools.build.cross_building import cross_building
 from conan.tools.build.flags import architecture_flag, architecture_link_flag, build_type_flags, cppstd_flag, \
-    build_type_link_flags, libcxx_flags, cstd_flag, llvm_clang_front
+    build_type_link_flags, libcxx_flags, cstd_flag, llvm_clang_front, threads_flag
 from conan.tools.env import Environment, VirtualBuildEnv
 from conan.tools.gnu.get_gnu_triplet import _get_gnu_triplet
 from conan.tools.microsoft import VCVars, msvc_runtime_flag, unix_path, check_min_vs, is_msvc
@@ -53,6 +53,7 @@ def __init__(self, conanfile, namespace=None, prefix="/"):
         self.cstd = cstd_flag(self._conanfile)
         self.arch_flag = architecture_flag(self._conanfile)
         self.arch_ld_flag = architecture_link_flag(self._conanfile)
+        self.threads_flag = threads_flag(self._conanfile)
         self.libcxx, self.gcc_cxx11_abi = libcxx_flags(self._conanfile)
         self.fpic = self._conanfile.options.get_safe("fPIC")
         self.msvc_runtime_flag = self._get_msvc_runtime_flag()
@@ -203,7 +204,7 @@ def _filter_list_empty_fields(v):
     def cxxflags(self):
         fpic = "-fPIC" if self.fpic else None
         ret = [self.libcxx, self.cppstd, self.arch_flag, fpic, self.msvc_runtime_flag,
-               self.sysroot_flag]
+               self.sysroot_flag, self.threads_flag]
         apple_flags = [self.apple_isysroot_flag, self.apple_arch_flag, self.apple_min_version_flag]
         apple_flags += self.apple_extra_flags
         conf_flags = self._conanfile.conf.get("tools.build:cxxflags", default=[], check_type=list)
@@ -214,7 +215,7 @@ def cxxflags(self):
     @property
     def cflags(self):
         fpic = "-fPIC" if self.fpic else None
-        ret = [self.cstd, self.arch_flag, fpic, self.msvc_runtime_flag, self.sysroot_flag]
+        ret = [self.cstd, self.arch_flag, fpic, self.msvc_runtime_flag, self.sysroot_flag, self.threads_flag]
         apple_flags = [self.apple_isysroot_flag, self.apple_arch_flag, self.apple_min_version_flag]
         apple_flags += self.apple_extra_flags
         conf_flags = self._conanfile.conf.get("tools.build:cflags", default=[], check_type=list)

conan/tools/gnu/gnutoolchain.py

@@ -7,7 +7,7 @@
 from conan.tools.build.cross_building import cross_building
 from conan.tools.build.flags import architecture_flag, architecture_link_flag, build_type_flags, cppstd_flag, \
     build_type_link_flags, \
-    libcxx_flags, llvm_clang_front
+    libcxx_flags, llvm_clang_front, threads_flag
 from conan.tools.env import Environment, VirtualBuildEnv
 from conan.tools.gnu.get_gnu_triplet import _get_gnu_triplet
 from conan.tools.microsoft import VCVars, msvc_runtime_flag, unix_path, check_min_vs, is_msvc
@@ -58,6 +58,7 @@ def __init__(self, conanfile, namespace=None, prefix="/"):
         self.cppstd = cppstd_flag(self._conanfile)
         self.arch_flag = architecture_flag(self._conanfile)
         self.arch_ld_flag = architecture_link_flag(self._conanfile)
+        self.threads_flag = threads_flag(self._conanfile)
         self.libcxx, self.gcc_cxx11_abi = libcxx_flags(self._conanfile)
         self.fpic = self._conanfile.options.get_safe("fPIC")
         self.msvc_runtime_flag = self._get_msvc_runtime_flag()
@@ -268,7 +269,7 @@ def _dict_to_list(flags):
     def cxxflags(self):
         fpic = "-fPIC" if self.fpic else None
         ret = [self.libcxx, self.cppstd, self.arch_flag, fpic, self.msvc_runtime_flag,
-               self.sysroot_flag]
+               self.sysroot_flag, self.threads_flag]
         apple_flags = [self.apple_isysroot_flag, self.apple_arch_flag, self.apple_min_version_flag]
         apple_flags += self.apple_extra_flags
         conf_flags = self._conanfile.conf.get("tools.build:cxxflags", default=[], check_type=list)
@@ -279,7 +280,7 @@ def cxxflags(self):
     @property
     def cflags(self):
         fpic = "-fPIC" if self.fpic else None
-        ret = [self.arch_flag, fpic, self.msvc_runtime_flag, self.sysroot_flag]
+        ret = [self.arch_flag, fpic, self.msvc_runtime_flag, self.sysroot_flag, self.threads_flag]
         apple_flags = [self.apple_isysroot_flag, self.apple_arch_flag, self.apple_min_version_flag]
         apple_flags += self.apple_extra_flags
         conf_flags = self._conanfile.conf.get("tools.build:cflags", default=[], check_type=list)
@@ -289,7 +290,7 @@ def cflags(self):
 
     @property
     def ldflags(self):
-        ret = [self.arch_flag, self.sysroot_flag, self.arch_ld_flag]
+        ret = [self.arch_flag, self.sysroot_flag, self.arch_ld_flag, self.threads_flag]
         apple_flags = [self.apple_isysroot_flag, self.apple_arch_flag, self.apple_min_version_flag]
         apple_flags += self.apple_extra_flags
         conf_flags = self._conanfile.conf.get("tools.build:sharedlinkflags", default=[],

conan/tools/meson/toolchain.py

@@ -9,7 +9,7 @@
 from conan.tools.apple.apple import is_apple_os, apple_min_version_flag, \
     resolve_apple_flags, apple_extra_flags
 from conan.tools.build.cross_building import cross_building
-from conan.tools.build.flags import architecture_link_flag, libcxx_flags, architecture_flag
+from conan.tools.build.flags import architecture_link_flag, libcxx_flags, architecture_flag, threads_flag
 from conan.tools.env import VirtualBuildEnv
 from conan.tools.meson.helpers import *
 from conan.tools.meson.helpers import get_apple_subsystem
@@ -218,6 +218,8 @@ def __init__(self, conanfile, backend=None, native=False):
         self.arch_flag = architecture_flag(self._conanfile)  # https://github.com/conan-io/conan/issues/17624
         #: Architecture link flag deduced by Conan and added to ``c_link_args`` and ``cpp_link_args``
         self.arch_link_flag = architecture_link_flag(self._conanfile)
+        #: Threads flag deduced by Conan and added to ``c_args``, ``cpp_args``, ``c_link_args`` and ``cpp_link_args``
+        self.threads_flag = threads_flag(self._conanfile)
         #: Dict-like object that defines Meson ``properties`` with ``key=value`` format
         self.properties = {}
         #: Dict-like object that defines Meson ``project options`` with ``key=value`` format
@@ -459,9 +461,9 @@ def _get_extra_flags(self):
         cflags += self.apple_extra_flags
         ld += self.apple_extra_flags
         return {
-            "cxxflags": [self.arch_flag] + cxxflags + sys_root + self.extra_cxxflags,
-            "cflags": [self.arch_flag] + cflags + sys_root + self.extra_cflags,
-            "ldflags": [self.arch_flag] + [self.arch_link_flag] + ld,
+            "cxxflags": [self.arch_flag] + cxxflags + sys_root + self.extra_cxxflags + [self.threads_flag],
+            "cflags": [self.arch_flag] + cflags + sys_root + self.extra_cflags + [self.threads_flag],
+            "ldflags": [self.arch_flag] + [self.arch_link_flag] + ld + self.extra_ldflags,
             "defines": [f"-D{d}" for d in (defines + self.extra_defines)]
         }
 

conan/tools/premake/toolchain.py

@@ -1,4 +1,4 @@
-from conan.tools.build.flags import architecture_flag, architecture_link_flag, libcxx_flags
+from conan.tools.build.flags import architecture_flag, architecture_link_flag, libcxx_flags, threads_flag
 import os
 import textwrap
 from pathlib import Path
@@ -47,27 +47,33 @@ def to_list(value):
     arch_flags = to_list(architecture_flag(self._conanfile))
     cxx_flags, libcxx_compile_definitions = libcxx_flags(self._conanfile)
     arch_link_flags = to_list(architecture_link_flag(self._conanfile))
+    threads_flags = to_list(threads_flag(self._conanfile))
 
     extra_defines = format_list(
         conanfile.conf.get("tools.build:defines", default=[], check_type=list)
         + self.extra_defines
         + to_list(libcxx_compile_definitions)
     )
     extra_c_flags = format_list(
-        conanfile.conf.get("tools.build:cflags", default=[], check_type=list) + self.extra_cflags + arch_flags
+        conanfile.conf.get("tools.build:cflags", default=[], check_type=list)
+        + self.extra_cflags
+        + arch_flags
+        + threads_flags
     )
     extra_cxx_flags = format_list(
         conanfile.conf.get("tools.build:cxxflags", default=[], check_type=list)
         + to_list(cxx_flags)
         + self.extra_cxxflags
         + arch_flags
+        + threads_flags
     )
     extra_ld_flags = format_list(
         conanfile.conf.get("tools.build:sharedlinkflags", default=[], check_type=list)
         + conanfile.conf.get("tools.build:exelinkflags", default=[], check_type=list)
         + self.extra_ldflags
         + arch_flags
         + arch_link_flags
+        + threads_flags
     )
 
     return (

test/unittests/client/build/compiler_flags_test.py

@@ -1,7 +1,7 @@
 import unittest
 from parameterized.parameterized import parameterized
 
-from conan.tools.build.flags import architecture_flag, build_type_flags
+from conan.tools.build.flags import architecture_flag, build_type_flags, threads_flag
 from conan.test.utils.mocks import MockSettings, ConanFileMock
 
 
@@ -37,6 +37,19 @@ def test_arch_flag(self, compiler, arch, the_os, flag):
         conanfile.settings = settings
         self.assertEqual(architecture_flag(conanfile), flag)
 
+
+    @parameterized.expand([("clang", None, ""),
+                           ("emcc", None, ""),
+                           ("emcc", "posix", "-pthread"),
+                           ("emcc", "wasm_workers", "-sWASM_WORKERS=1"),
+                           ])
+    def test_threads_flag(self, compiler, threads, flag):
+        settings = MockSettings({"compiler": compiler,
+                                 "compiler.threads": threads})
+        conanfile = ConanFileMock()
+        conanfile.settings = settings
+        self.assertEqual(threads_flag(conanfile), flag)
+
     @parameterized.expand([("clang", "x86", "Windows", ""),
                            ("clang", "x86_64", "Windows", "")
                            ])