Ccache

docs/emcc.txt

@@ -645,6 +645,8 @@ Environment variables
 
    * "EM_CONFIG" [general]
 
+   * "EM_LLVM_ROOT" [compile+link]
+
 Search for 'os.environ' in emcc.py to see how these are used. The most
 interesting is possibly "EMCC_DEBUG", which forces the compiler to
 dump its build and temporary files to a temporary directory where they

em++

@@ -26,4 +26,9 @@ if [ -z "$PYTHON" ]; then
   exit 1
 fi
 
-exec "$PYTHON" "$0.py" "$@"
+if [ -z "$EMCC_CCACHE" ]; then
+  exec "$PYTHON" "$0.py" "$@"
+else
+  unset EMCC_CCACHE
+  exec ccache "$0" "$@"
+fi

em++.bat

@@ -8,4 +8,11 @@
   set EM_PY=python
 )
 
-@"%EM_PY%" "%~dp0\%~n0.py" %*
+@if "%EMCC_CCACHE%"=="" (
+  :: Do regular invocation of em++.py compiler
+  "%EM_PY%" "%~dp0\%~n0.py" %*
+) else (
+  :: Remove the ccache env. var, invoke ccache and re-enter this script to take the above branch.
+  set EMCC_CCACHE=
+  ccache "%~dp0\%~n0.bat" %*
+)

emcc

@@ -26,4 +26,9 @@ if [ -z "$PYTHON" ]; then
   exit 1
 fi
 
-exec "$PYTHON" "$0.py" "$@"
+if [ -z "$EMCC_CCACHE" ]; then
+  exec "$PYTHON" "$0.py" "$@"
+else
+  unset EMCC_CCACHE
+  exec ccache "$0" "$@"
+fi

emcc.bat

@@ -8,4 +8,11 @@
   set EM_PY=python
 )
 
-@"%EM_PY%" "%~dp0\%~n0.py" %*
+@if "%EMCC_CCACHE%"=="" (
+  :: Do regular invocation of em++.py compiler
+  "%EM_PY%" "%~dp0\%~n0.py" %*
+) else (
+  :: Remove the ccache env. var, invoke ccache and re-enter this script to take the above branch.
+  set EMCC_CCACHE=
+  ccache "%~dp0\%~n0.bat" %*
+)

site/source/docs/tools_reference/emcc.rst

@@ -540,6 +540,7 @@ Environment variables
   - ``EMCC_SKIP_SANITY_CHECK`` [general]
   - ``EM_IGNORE_SANITY`` [general]
   - ``EM_CONFIG`` [general]
+  - ``EM_LLVM_ROOT`` [compile+link]
 
 Search for 'os.environ' in `emcc.py <https://github.com/emscripten-core/emscripten/blob/main/emcc.py>`_ to see how these are used. The most interesting is possibly ``EMCC_DEBUG``, which forces the compiler to dump its build and temporary files to a temporary directory where they can be reviewed.
 

src/settings.js

@@ -1187,7 +1187,7 @@ var DYNAMIC_EXECUTION = 1;
 var BOOTSTRAPPING_STRUCT_INFO = 0;
 
 // Add some calls to emscripten tracing APIs
-// [link]
+// [compile+link]
 var EMSCRIPTEN_TRACING = 0;
 
 // Specify the GLFW version that is being linked against.  Only relevant, if you

tools/create_entry_points.py

@@ -7,25 +7,28 @@
 """Tool for creating/maintains the python launcher scripts for all the emscripten
 python tools.
 
-This tools makes copies or `run_python.sh` and `run_python.bat` script for each
-entry point.  On UNIX we previously used symbolic links for simplicity but this
-breaks MINGW users on windows who want use the shell script launcher but don't
-have symlink support (sigh).
+This tools makes copies or `run_python.sh/.bat` and `run_python_compiler.sh/.bat`
+script for each entry point. On UNIX we previously used symbolic links for
+simplicity but this breaks MINGW users on windows who want use the shell script
+launcher but don't have symlink support.
 """
 
 import os
 import shutil
 import sys
 
+compiler_entry_points = '''
+emcc
+em++
+'''.split()
+
 entry_points = '''
 emar
 embuilder
-emcc
 emcmake
 em-config
 emconfigure
 emmake
-em++
 emranlib
 emrun
 emscons
@@ -39,13 +42,23 @@
 def main():
   tools_dir = os.path.dirname(os.path.abspath(__file__))
   root_dir = os.path.dirname(tools_dir)
-  sh_file = os.path.join(tools_dir, 'run_python.sh')
-  bat_file = os.path.join(tools_dir, 'run_python.bat')
-  for entry_point in entry_points:
-    if os.path.exists(os.path.join(root_dir, entry_point)):
-        os.remove(os.path.join(root_dir, entry_point))
-    shutil.copy2(sh_file, os.path.join(root_dir, entry_point))
-    shutil.copy2(bat_file, os.path.join(root_dir, entry_point) + '.bat')
+
+  def generate_entry_points(cmd, path):
+    sh_file = path + '.sh'
+    bat_file = path + '.bat'
+    for entry_point in cmd:
+      dst = os.path.join(root_dir, entry_point)
+      if os.path.exists(dst):
+          os.remove(dst)
+      shutil.copy2(sh_file, dst)
+
+      dst += '.bat'
+      if os.path.exists(dst):
+          os.remove(dst)
+      shutil.copy2(bat_file, dst)
+
+  generate_entry_points(entry_points, os.path.join(tools_dir, 'run_python'))
+  generate_entry_points(compiler_entry_points, os.path.join(tools_dir, 'run_python_compiler'))
 
 
 if __name__ == '__main__':

tools/run_python_compiler.bat

@@ -0,0 +1,18 @@
+:: Entry point for running python scripts on windows systems.
+:: To modify this file, edit `tools/run_python.bat` and then run
+:: `tools/create_entry_points.py`
+
+@setlocal
+@set EM_PY=%EMSDK_PYTHON%
+@if "%EM_PY%"=="" (
+  set EM_PY=python
+)
+
+@if "%EMCC_CCACHE%"=="" (
+  :: Do regular invocation of em++.py compiler
+  "%EM_PY%" "%~dp0\%~n0.py" %*
+) else (
+  :: Remove the ccache env. var, invoke ccache and re-enter this script to take the above branch.
+  set EMCC_CCACHE=
+  ccache "%~dp0\%~n0.bat" %*
+)

tools/run_python_compiler.sh

@@ -0,0 +1,34 @@
+#!/bin/sh
+# Copyright 2020 The Emscripten Authors.  All rights reserved.
+# Emscripten is available under two separate licenses, the MIT license and the
+# University of Illinois/NCSA Open Source License.  Both these licenses can be
+# found in the LICENSE file.
+#
+# Entry point for running python scripts on UNIX systems.
+#
+# To modify this file, edit `tools/run_python.sh` and then run
+# `tools/create_entry_points.py`
+
+if [ -z "$PYTHON" ]; then
+  PYTHON=$EMSDK_PYTHON
+fi
+
+if [ -z "$PYTHON" ]; then
+  PYTHON=$(which python3 2> /dev/null)
+fi
+
+if [ -z "$PYTHON" ]; then
+  PYTHON=$(which python 2> /dev/null)
+fi
+
+if [ -z "$PYTHON" ]; then
+  echo 'unable to find python in $PATH'
+  exit 1
+fi
+
+if [ -z "$EMCC_CCACHE" ]; then
+  exec "$PYTHON" "$0.py" "$@"
+else
+  unset EMCC_CCACHE
+  exec ccache "$0" "$@"
+fi