feature: allow to skip wasm-opt when invoked by clang

By exporting the WASMLABS_SKIP_WASM_OPT envvar, the wasm-opt wrapper
present in the wasm-base container image will make the wasm-opt call a
no-op.

This is useful for cases when we don't desire wasm-opt to be called,
for example when invoked directly by
clang (llvm/llvm-project#55781).

Dockerfile.wasm-base

@@ -1,9 +1,16 @@
 FROM ubuntu:20.04
-ARG BINARYEN_VERSION=111
+ARG BINARYEN_VERSION
+ENV BINARYEN_PATH=/opt
 RUN apt update && \
     DEBIAN_FRONTEND=noninteractive apt install -y \
       wget && \
     wget https://github.com/WebAssembly/binaryen/releases/download/version_${BINARYEN_VERSION}/binaryen-version_${BINARYEN_VERSION}-x86_64-linux.tar.gz && \
     tar -xf binaryen-version_${BINARYEN_VERSION}-x86_64-linux.tar.gz --strip-components=1 -C /opt && \
-    rm binaryen-version_${BINARYEN_VERSION}-x86_64-linux.tar.gz
-ENV PATH="$PATH:/opt/bin"
+    rm binaryen-version_${BINARYEN_VERSION}-x86_64-linux.tar.gz && \
+    mkdir -p /opt/priority-bin
+# wasm-opt is called in unexpected contexts
+# (https://github.com/llvm/llvm-project/issues/55781). To avoid this,
+# we install a `wasm-opt` wrapper with a higher priority in the PATH
+# that can disable wasm-opt execution when desired.
+ADD images/wasm-base/wasm-opt /opt/priority-bin/
+ENV PATH="/opt/priority-bin:$PATH:/opt/bin"

images/wasm-base/wasm-opt

@@ -0,0 +1,42 @@
+#!//usr/bin/env bash
+# Inspired by https://raw.githubusercontent.com/ruby/ruby/df6b72b8ff7af16a56fa48f3b4abb1d8850f4d1c/wasm/wasm-opt
+#
+# A fake wasm-opt, which does nothing at all
+# See also: tool/wasm-clangw
+
+if [[ -z "${WASMLABS_SKIP_WASM_OPT}" ]]; then
+   exec $BINARYEN_PATH/bin/wasm-opt "$@"
+fi
+
+set -e
+input=
+output=
+while [ $# -ne 0 ]; do
+  case "$1" in
+    -o)
+      shift
+      output=$1
+  ;;
+    -*)
+      # ignore other options
+  ;;
+    *)
+      input=$1
+  ;;
+  esac
+  shift
+done
+
+if [ -z "$input" ]; then
+  echo "missing input binary"
+  exit 1
+fi
+
+if [ -z "$output" ]; then
+  echo "missing output binary"
+  exit 1
+fi
+
+if [ "$input" != "$output" ]; then
+  cp "$input" "$output"
+fi

php/php-7.3.33/wl-build.sh

@@ -31,7 +31,16 @@ logStatus "Configuring build with '${PHP_CONFIGURE}'... "
 ./configure --host=wasm32-wasi host_alias=wasm32-musl-wasi --target=wasm32-wasi target_alias=wasm32-musl-wasi ${PHP_CONFIGURE} || exit 1
 
 logStatus "Building php-cgi... "
+# By exporting WASMLABS_SKIP_WASM_OPT envvar during the build, the
+# wasm-opt wrapper in the wasm-base image will be a dummy wrapper that
+# is effectively a NOP.
+#
+# This is due to https://github.com/llvm/llvm-project/issues/55781, so
+# that we get to choose which optimization passes are executed after
+# the artifacts have been built.
+export WASMLABS_SKIP_WASM_OPT=1
 make cgi || exit 1
+unset WASMLABS_SKIP_WASM_OPT
 
 logStatus "Preparing artifacts... "
 mkdir -p ${WASMLABS_OUTPUT}/bin 2>/dev/null || exit 1

php/php-7.4.32/wl-build.sh

@@ -43,7 +43,16 @@ then
 fi
 
 logStatus "Building '${MAKE_TARGETS}'... "
+# By exporting WASMLABS_SKIP_WASM_OPT envvar during the build, the
+# wasm-opt wrapper in the wasm-base image will be a dummy wrapper that
+# is effectively a NOP.
+#
+# This is due to https://github.com/llvm/llvm-project/issues/55781, so
+# that we get to choose which optimization passes are executed after
+# the artifacts have been built.
+export WASMLABS_SKIP_WASM_OPT=1
 make -j ${MAKE_TARGETS} || exit 1
+unset WASMLABS_SKIP_WASM_OPT
 
 logStatus "Preparing artifacts... "
 mkdir -p ${WASMLABS_OUTPUT}/bin 2>/dev/null || exit 1

php/php-8.1.11/wl-build.sh

@@ -35,7 +35,16 @@ logStatus "Configuring build with '${PHP_CONFIGURE}'... "
 ./configure --host=wasm32-wasi host_alias=wasm32-musl-wasi --target=wasm32-wasi target_alias=wasm32-musl-wasi ${PHP_CONFIGURE} || exit 1
 
 logStatus "Building php-cgi... "
+# By exporting WASMLABS_SKIP_WASM_OPT envvar during the build, the
+# wasm-opt wrapper in the wasm-base image will be a dummy wrapper that
+# is effectively a NOP.
+#
+# This is due to https://github.com/llvm/llvm-project/issues/55781, so
+# that we get to choose which optimization passes are executed after
+# the artifacts have been built.
+export WASMLABS_SKIP_WASM_OPT=1
 make cgi  || exit 1
+unset WASMLABS_SKIP_WASM_OPT
 
 logStatus "Preparing artifacts... "
 mkdir -p ${WASMLABS_OUTPUT}/bin 2>/dev/null || exit 1

php/php-8.2.0/wl-build.sh

@@ -46,7 +46,16 @@ then
 fi
 
 logStatus "Building '${MAKE_TARGETS}'... "
+# By exporting WASMLABS_SKIP_WASM_OPT envvar during the build, the
+# wasm-opt wrapper in the wasm-base image will be a dummy wrapper that
+# is effectively a NOP.
+#
+# This is due to https://github.com/llvm/llvm-project/issues/55781, so
+# that we get to choose which optimization passes are executed after
+# the artifacts have been built.
+export WASMLABS_SKIP_WASM_OPT=1
 make -j ${MAKE_TARGETS} || exit 1
+unset WASMLABS_SKIP_WASM_OPT
 
 logStatus "Preparing artifacts... "
 mkdir -p ${WASMLABS_OUTPUT}/bin 2>/dev/null || exit 1