From 4f0484fca22ab4a7c93087cd2a6b74b4735cdde3 Mon Sep 17 00:00:00 2001
From: Santiago Palladino <santiago@aztecprotocol.com>
Date: Wed, 5 Apr 2023 10:12:19 +0100
Subject: [PATCH] Build a3crypto.wasm (#311)

* Build a3crypto.wasm

Builds a smaller wasm than full barretenberg with crypto primitives to be used from aztec3-packages.

* Rename to primitives and remove asyncify

* Add missing modules for tests
---
 cpp/dockerfiles/Dockerfile.wasm-linux-clang |  5 ++--
 cpp/src/CMakeLists.txt                      | 32 ++++++++++++++++++++-
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/cpp/dockerfiles/Dockerfile.wasm-linux-clang b/cpp/dockerfiles/Dockerfile.wasm-linux-clang
index f4a19bba53..d1c41f0ce7 100644
--- a/cpp/dockerfiles/Dockerfile.wasm-linux-clang
+++ b/cpp/dockerfiles/Dockerfile.wasm-linux-clang
@@ -5,10 +5,11 @@ WORKDIR /usr/src/barretenberg/cpp/src
 RUN curl -s -L https://github.com/CraneStation/wasi-sdk/releases/download/wasi-sdk-12/wasi-sdk-12.0-linux.tar.gz | tar zxfv -
 WORKDIR /usr/src/barretenberg/cpp
 COPY . .
-# Build both honk_tests barretenberg.wasm
+# Build both honk_tests barretenberg.wasm primitives.wasm
 # This ensures that we aren't using features that would be incompatible with WASM for Honk
-RUN cmake --preset wasm && cmake --build --preset wasm --target honk_tests --target barretenberg.wasm
+RUN cmake --preset wasm && cmake --build --preset wasm --target honk_tests --target barretenberg.wasm --target primitives.wasm
 
 FROM alpine:3.17
 COPY --from=builder /usr/src/barretenberg/cpp/build-wasm/bin/barretenberg.wasm /usr/src/barretenberg/cpp/build/bin/barretenberg.wasm
+COPY --from=builder /usr/src/barretenberg/cpp/build-wasm/bin/primitives.wasm /usr/src/barretenberg/cpp/build/bin/primitives.wasm
 COPY --from=builder /usr/src/barretenberg/cpp/build-wasm/bin/*_tests /usr/src/barretenberg/cpp/build/bin/
diff --git a/cpp/src/CMakeLists.txt b/cpp/src/CMakeLists.txt
index f82e5d0d72..6ccdebdf0e 100644
--- a/cpp/src/CMakeLists.txt
+++ b/cpp/src/CMakeLists.txt
@@ -112,12 +112,35 @@ if(WASM)
         -nostartfiles -O2 -Wl,--no-entry -Wl,--export-dynamic -Wl,--import-memory -Wl,--allow-undefined -Wl,--stack-first -Wl,-z,stack-size=1048576
     )
 
+    # Repeat the above but for the smaller primitives.wasm
+    # Used in packages where we don't need the full contents of barretenberg
+    add_executable(
+        primitives.wasm
+        $<TARGET_OBJECTS:srs_objects>
+        $<TARGET_OBJECTS:numeric_objects>
+        $<TARGET_OBJECTS:crypto_sha256_objects>
+        $<TARGET_OBJECTS:crypto_aes128_objects>
+        $<TARGET_OBJECTS:crypto_blake2s_objects>
+        $<TARGET_OBJECTS:crypto_blake3s_objects>
+        $<TARGET_OBJECTS:crypto_generators_objects>
+        $<TARGET_OBJECTS:crypto_keccak_objects>
+        $<TARGET_OBJECTS:crypto_schnorr_objects>
+        $<TARGET_OBJECTS:crypto_pedersen_hash_objects>
+        $<TARGET_OBJECTS:crypto_pedersen_commitment_objects>
+        $<TARGET_OBJECTS:ecc_objects>
+    )
+
+    target_link_options(
+        primitives.wasm
+        PRIVATE
+        -nostartfiles -O2 -Wl,--no-entry -Wl,--export-dynamic -Wl,--import-memory -Wl,--allow-undefined -Wl,--stack-first -Wl,-z,stack-size=1048576
+    )
+
     # TODO(blaine): Figure out how to Asyncify the wasm output.
     # Binaryen's Asyncify transform produces wasm that has too many local variables to run in a WebAssembly
     # instance. This likely would be "solved" by enabling the optimizations to reduce the number of locals,
     # but using any optimization level results in a wasm file that takes an unusable amount of time to solve the
     # most simple prood.
-
     # find_program(WASM_OPT wasm-opt)
 
     # if(NOT WASM_OPT)
@@ -131,6 +154,13 @@ if(WASM)
     #     VERBATIM
     # )
 
+    add_custom_command(
+        TARGET primitives.wasm
+        POST_BUILD
+        COMMAND wasm-opt "$<TARGET_FILE:primitives.wasm>" -O2 -o "$<TARGET_FILE:primitives.wasm>"
+        VERBATIM
+    )
+
     if(INSTALL_BARRETENBERG)
         install(TARGETS barretenberg.wasm DESTINATION ${CMAKE_INSTALL_BINDIR})
     endif()