Move emscripten_atomics_is_lock_free to atomic.h. NFC

This function is generally useful for either pthreads or wasm worker
builds.  Putting it in `atomic.h` and `libatomic.js` make sense.

Also remove the duplicate `emscripten_navigator_hardware_concurrency`
function which duplicates the existing `emscripten_num_logical_cores`.

Also, change the return type of `emscripten_atomics_is_lock_free` to
be `bool`, which better represents its type.

Author: sbc100

Diff for: src/lib/libatomic.js

@@ -149,6 +149,8 @@ addToLibrary({
     return numCancelled;
   },
 
+  emscripten_atomics_is_lock_free: (width) => Atomics.isLockFree(width),
+
   emscripten_has_threading_support: () => typeof SharedArrayBuffer != 'undefined',
 
   emscripten_num_logical_cores: () =>

Diff for: src/lib/libsigs.js

@@ -710,7 +710,6 @@ sigs = {
   emscripten_math_sqrt__sig: 'dd',
   emscripten_math_tan__sig: 'dd',
   emscripten_math_tanh__sig: 'dd',
-  emscripten_navigator_hardware_concurrency__sig: 'i',
   emscripten_notify_memory_growth__sig: 'vp',
   emscripten_num_logical_cores__sig: 'i',
   emscripten_out__sig: 'vp',

Diff for: src/lib/libwasm_worker.js

@@ -284,17 +284,6 @@ if (ENVIRONMENT_IS_WASM_WORKER
     _wasmWorkers[id].postMessage({'_wsc': funcPtr, 'x': readEmAsmArgs(sigPtr, varargs) });
   },
 
-  emscripten_navigator_hardware_concurrency: () => {
-#if ENVIRONMENT_MAY_BE_NODE
-    if (ENVIRONMENT_IS_NODE) return require('os').cpus().length;
-#endif
-    return navigator['hardwareConcurrency'];
-  },
-
-  emscripten_atomics_is_lock_free: (width) => {
-    return Atomics.isLockFree(width);
-  },
-
   emscripten_lock_async_acquire__deps: ['$polyfillWaitAsync'],
   emscripten_lock_async_acquire: (lock, asyncWaitFinished, userData, maxWaitMilliseconds) => {
     let dispatch = (val, ret) => {

Diff for: system/include/emscripten/atomic.h

@@ -17,6 +17,25 @@ extern "C" {
 
 #define _EM_INLINE static __inline__ __attribute__((always_inline, nodebug))
 
+// Returns true if the current environment is able to spawn threads and
+// the program was built with threading support enabled. If this returns 0,
+// calls to pthread_create() or the creation of wasm workers will fail.
+int emscripten_has_threading_support(void);
+
+// Returns the number of logical cores on the system.
+int emscripten_num_logical_cores(void);
+
+// Alias for emscripten_num_logical_cores
+#define emscripten_navigator_hardware_concurrency emscripten_num_logical_cores
+
+// Returns the value of the expression "Atomics.isLockFree(byteWidth)": true if
+// the given memory access width can be accessed atomically, and false
+// otherwise. Generally will return true on 1, 2 and 4 byte accesses. On 8 byte
+// accesses, behavior differs across browsers, see
+//  - https://bugzilla.mozilla.org/show_bug.cgi?id=1246139
+//  - https://bugs.chromium.org/p/chromium/issues/detail?id=1167449
+bool emscripten_atomics_is_lock_free(int byteWidth);
+
 // Note on 64bit atomics ops: All 64-bit atomic ops defined here, while single
 // instruction under wasm, will be emulated by using locks in wasm2js mode.
 // This is also true for C/C++ native atomics as well as intrinsics.

Diff for: system/include/emscripten/threading.h

@@ -20,15 +20,6 @@
 extern "C" {
 #endif
 
-// Returns true if the current browser is able to spawn threads with
-// pthread_create(), and the compiled page was built with threading support
-// enabled. If this returns 0, calls to pthread_create() will fail with return
-// code EAGAIN.
-int emscripten_has_threading_support(void);
-
-// Returns the number of logical cores on the system.
-int emscripten_num_logical_cores(void);
-
 // If the given memory address contains value val, puts the calling thread to
 // sleep waiting for that address to be notified.
 // Returns -EINVAL if addr is null.

Diff for: system/include/emscripten/wasm_worker.h

@@ -101,22 +101,6 @@ void emscripten_wasm_worker_post_function_sig(emscripten_wasm_worker_t id, void
 // https://github.com/WebAssembly/threads/issues/174
 void emscripten_wasm_worker_sleep(int64_t nanoseconds);
 
-// Returns the value of navigator.hardwareConcurrency, i.e. the number of
-// logical threads available for the user agent. NOTE: If the execution
-// environment does not support navigator.hardwareConcurrency, this function
-// will return zero to signal no support. (If the value 1 is returned, then it
-// means that navigator.hardwareConcurrency is supported, but there is only one
-// logical thread of concurrency available)
-int emscripten_navigator_hardware_concurrency(void);
-
-// Returns the value of the expression "Atomics.isLockFree(byteWidth)": true if
-// the given memory access width can be accessed atomically, and false
-// otherwise. Generally will return true on 1, 2 and 4 byte accesses. On 8 byte
-// accesses, behavior differs across browsers, see
-//  - https://bugzilla.mozilla.org/show_bug.cgi?id=1246139
-//  - https://bugs.chromium.org/p/chromium/issues/detail?id=1167449
-int emscripten_atomics_is_lock_free(int byteWidth);
-
 #define emscripten_lock_t volatile uint32_t
 
 // Use with syntax "emscripten_lock_t l = EMSCRIPTEN_LOCK_T_STATIC_INITIALIZER;"