Use EMCC_CFLAGS="-Oz" during Emscripten llvm build to reduce CppInterOp shared library size to 48Mb

Author: mcbarton

.github/workflows/emscripten.yml

@@ -195,7 +195,7 @@ jobs:
                         -DCLANG_BUILD_TOOLS=OFF                         \
                         -DLLVM_NATIVE_TOOL_DIR=$NATIVE_DIR 		\
                          ../llvm
-          emmake ninja clang cling lld gtest_main
+          EMCC_CFLAGS="-Oz" emmake ninja clang cling lld gtest_main
         else
           # Apply patches
           llvm_vers=$(echo "${{ matrix.clang-runtime }}" | tr '[:lower:]' '[:upper:]')
@@ -226,7 +226,7 @@ jobs:
                         -G Ninja                                         \
                         -DLLVM_NATIVE_TOOL_DIR=$NATIVE_DIR 		\
                         ../llvm
-          emmake ninja libclang clangInterpreter clangStaticAnalyzerCore lldWasm
+          EMCC_CFLAGS="-Oz" emmake ninja libclang clangInterpreter clangStaticAnalyzerCore lldWasm
         fi
         cd ../
         rm -rf $(find . -maxdepth 1 ! -name "build" ! -name "llvm" ! -name "clang" ! -name ".")
@@ -296,7 +296,7 @@ jobs:
                         -DLLVM_ENABLE_LIBPFM=OFF                        `
                         -DCLANG_BUILD_TOOLS=OFF                         `
                 ..\llvm
-          emmake make clang cling lld gtest_main
+          $env:EMCC_CFLAGS="-Oz" emmake make clang cling lld gtest_main
         }
         else
         {
@@ -337,7 +337,7 @@ jobs:
                         -DCLANG_BUILD_TOOLS=OFF                         `
                         -G Ninja `
                         ..\llvm
-          emmake ninja libclang clangInterpreter clangStaticAnalyzerCore lldWasm
+          $env:EMCC_CFLAGS="-Oz" emmake ninja libclang clangInterpreter clangStaticAnalyzerCore lldWasm
         }
         cd ..\
         rm -r -force $(find.exe . -maxdepth 1 ! -name "build" ! -name "llvm" ! -name "clang" ! -name ".")

Emscripten-build-instructions.md

@@ -100,9 +100,9 @@ emcmake cmake -DCMAKE_BUILD_TYPE=Release \
                         -DCLANG_BUILD_TOOLS=OFF                         \
                         -DLLVM_NATIVE_TOOL_DIR=$NATIVE_DIR              \
                         ../llvm
-emmake make libclang -j $(nproc --all)
-emmake make clangInterpreter clangStaticAnalyzerCore -j $(nproc --all)
-emmake make lldWasm -j $(nproc --all)
+EMCC_CFLAGS="-Oz" emmake make libclang -j $(nproc --all)
+EMCC_CFLAGS="-Oz" emmake make clangInterpreter clangStaticAnalyzerCore -j $(nproc --all)
+EMCC_CFLAGS="-Oz" emmake make lldWasm -j $(nproc --all)
 ```
 
 or executing
@@ -131,7 +131,7 @@ emcmake cmake -DCMAKE_BUILD_TYPE=Release `
                         -DCLANG_BUILD_TOOLS=OFF                         `
                         -G Ninja `
                         ..\llvm
-emmake ninja libclang clangInterpreter clangStaticAnalyzerCore lldWasm
+$env:EMCC_CFLAGS="-Oz" emmake ninja libclang clangInterpreter clangStaticAnalyzerCore lldWasm
 ```
 
 on Windows. Once this finishes building we need to take note of where we built our llvm build. This can be done by executing the following on Linux and osx

docs/Emscripten-build-instructions.rst

@@ -120,9 +120,9 @@ and osx
                  -DCLANG_BUILD_TOOLS=OFF                         \
                  -DLLVM_NATIVE_TOOL_DIR=$NATIVE_DIR 		\
                  ../llvm
-   emmake make libclang -j $(nproc --all)
-   emmake make clangInterpreter clangStaticAnalyzerCore -j $(nproc --all)
-   emmake make lldWasm -j $(nproc --all)
+   EMCC_CFLAGS="-Oz" emmake make libclang -j $(nproc --all)
+   EMCC_CFLAGS="-Oz" emmake make clangInterpreter clangStaticAnalyzerCore -j $(nproc --all)
+   EMCC_CFLAGS="-Oz" emmake make lldWasm -j $(nproc --all)
 
 or executing
 
@@ -151,7 +151,7 @@ or executing
                         -DCLANG_BUILD_TOOLS=OFF                         `
                         -G Ninja `
                         ..\llvm
-   emmake ninja libclang clangInterpreter clangStaticAnalyzerCore lldWasm
+   $env:EMCC_CFLAGS="-Oz" emmake ninja libclang clangInterpreter clangStaticAnalyzerCore lldWasm
 
 on Windows. Once this finishes building we need to take note of where we built our llvm build.
 This can be done by executing the following on Linux and osx