Use patched secp256k1-sys

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "util/gen-fixtures/secp256k1"]
+	path = util/gen-fixtures/secp256k1
+	url = https://github.com/bitcoin-core/secp256k1.git

.prettierignore

@@ -1 +1,2 @@
 /target
+/util/gen-fixtures/secp256k1

Makefile

@@ -3,6 +3,8 @@ build-wasm-cp = cp -f target/wasm32-unknown-unknown/$(1)/tiny_secp256k1_wasm.was
 build-wasm:
 	cargo build --target wasm32-unknown-unknown --release
 	$(call build-wasm-cp,release)
+	wasm-opt --strip-debug --strip-producers --output lib/secp256k1.wasm lib/secp256k1.wasm
+	node ./util/wasm-strip.js lib/secp256k1.wasm
 	wasm-opt -O4 --output lib/secp256k1.wasm lib/secp256k1.wasm
 
 build-wasm-debug:
@@ -15,7 +17,7 @@ format:
 
 lint:
 	cargo fmt -- --check
-	cargo clippy
+	cargo clippy --target wasm32-unknown-unknown
 	npx prettier -c .
 
 test:

package.json

@@ -13,6 +13,7 @@
   "license": "MIT",
   "main": "lib/index.js",
   "devDependencies": {
+    "binaryen": "^100.0.0",
     "prettier": "^2.2.1",
     "tap-difflet": "^0.7.2",
     "tape": "^5.2.2"

secp256k1-wasm/Cargo.toml

@@ -11,4 +11,5 @@ publish = false
 crate-type = ["cdylib"]
 
 [dependencies]
-secp256k1-sys = "0.4.0"
+# `[patch.crates-io]` is not working :(
+secp256k1-sys = { version = "0.4.0", default-features = false, git = "https://github.com/fanatid/rust-secp256k1", branch = "more-features" }

secp256k1-wasm/src/lib.rs

@@ -1,3 +1,14 @@
+#![no_std]
+#![feature(core_intrinsics)]
+
+#[panic_handler]
+fn panic(_info: &core::panic::PanicInfo) -> ! {
+    core::intrinsics::abort()
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+compile_error!("Only `wasm32` target_arch is supported.");
+
 use secp256k1_sys::{
     secp256k1_context_no_precomp, secp256k1_context_preallocated_create,
     secp256k1_context_preallocated_size, secp256k1_context_randomize, secp256k1_ec_pubkey_combine,
@@ -75,30 +86,32 @@ fn initialize_context_seed() {
     unsafe {
         for offset in (0..8).map(|v| v * 4) {
             let value = generate_int32();
-            let bytes: [u8; 4] = std::mem::transmute(value);
+            let bytes: [u8; 4] = core::mem::transmute(value);
             CONTEXT_SEED[offset..offset + 4].copy_from_slice(&bytes);
         }
     }
 }
 
 fn get_context() -> *const Context {
-    static mut CONTEXT: *const Context = std::ptr::null();
-    static ONCE: std::sync::Once = std::sync::Once::new();
-    ONCE.call_once(|| unsafe {
-        let size =
-            secp256k1_context_preallocated_size(SECP256K1_START_SIGN | SECP256K1_START_VERIFY);
-        assert_eq!(size, CONTEXT_BUFFER.len());
-        let ctx = secp256k1_context_preallocated_create(
-            CONTEXT_BUFFER.as_ptr() as *mut c_void,
-            SECP256K1_START_SIGN | SECP256K1_START_VERIFY,
-        );
-        initialize_context_seed();
-        let retcode = secp256k1_context_randomize(ctx, CONTEXT_SEED.as_ptr());
-        CONTEXT_SEED.fill(0);
-        assert_eq!(retcode, 1);
-        CONTEXT = ctx
-    });
-    unsafe { CONTEXT }
+    static mut CONTEXT: *const Context = core::ptr::null();
+    unsafe {
+        if CONTEXT_SEED[0] == 0 {
+            let size =
+                secp256k1_context_preallocated_size(SECP256K1_START_SIGN | SECP256K1_START_VERIFY);
+            assert_eq!(size, CONTEXT_BUFFER.len());
+            let ctx = secp256k1_context_preallocated_create(
+                CONTEXT_BUFFER.as_ptr() as *mut c_void,
+                SECP256K1_START_SIGN | SECP256K1_START_VERIFY,
+            );
+            initialize_context_seed();
+            let retcode = secp256k1_context_randomize(ctx, CONTEXT_SEED.as_ptr());
+            CONTEXT_SEED[0] = 1;
+            CONTEXT_SEED[1..].fill(0);
+            assert_eq!(retcode, 1);
+            CONTEXT = ctx
+        }
+        CONTEXT
+    }
 }
 
 unsafe fn pubkey_parse(input: *const u8, inputlen: usize) -> InvalidInputResult<PublicKey> {
@@ -262,7 +275,7 @@ pub extern "C" fn sign(extra_data: i32) {
     unsafe {
         let mut sig = Signature::new();
         let noncedata = if extra_data == 0 {
-            std::ptr::null()
+            core::ptr::null()
         } else {
             EXTRA_DATA_INPUT.as_ptr()
         } as *const c_void;

util/gen-fixtures/Makefile

@@ -0,0 +1,29 @@
+all: json-privates json-points json-ecdsa
+
+.PHONY: secp256k1
+secp256k1:
+	cd secp256k1 && ./autogen.sh && ./configure && make
+
+privates: secp256k1
+privates: privates.cpp shared.hpp
+	g++ $< -Lsecp256k1/.libs/ -lgmp -l:libsecp256k1.a -o $@
+
+points: secp256k1
+points: points.cpp shared.hpp
+	g++ $< -Lsecp256k1/.libs/ -lgmp -l:libsecp256k1.a -o $@
+
+ecdsa: secp256k1
+ecdsa: ecdsa.cpp shared.hpp
+	g++ $< -Lsecp256k1/.libs/ -lgmp -lcrypto -lssl -l:libsecp256k1.a -o $@
+
+clean:
+	rm privates points ecdsa && cd secp256k1 && make clean
+
+json-points: points
+	./points | jq . > ../../tests/fixtures/points.json
+
+json-privates: privates
+	./privates | jq . > ../../tests/fixtures/privates.json
+
+json-ecdsa: ecdsa
+	./ecdsa | jq . > ../../tests/fixtures/ecdsa.json

scripts/shared.hpp → util/gen-fixtures/shared.hpp

@@ -7,7 +7,7 @@
 #include <sstream>
 #include <vector>
 
-#include "../native/secp256k1/include/secp256k1.h"
+#include "secp256k1/include/secp256k1.h"
 #include "hexxer.hpp"
 #include "json.hpp"
 

util/wasm-strip.js

@@ -0,0 +1,73 @@
+const fs = require("fs");
+const binaryen = require("binaryen");
+
+const NOT_USED_FUNCTIONS = [
+  "rustsecp256k1_v0_4_0_default_error_callback_fn",
+  "rustsecp256k1_v0_4_0_default_illegal_callback_fn",
+  "rustsecp256k1_v0_4_0_context_preallocated_clone_size",
+  "rustsecp256k1_v0_4_0_context_preallocated_clone",
+  "rustsecp256k1_v0_4_0_context_preallocated_destroy",
+  "rustsecp256k1_v0_4_0_context_set_illegal_callback",
+  "rustsecp256k1_v0_4_0_context_set_error_callback",
+  "rustsecp256k1_v0_4_0_ecdsa_signature_parse_der",
+  "rustsecp256k1_v0_4_0_ecdsa_signature_serialize_der",
+  "rustsecp256k1_v0_4_0_ec_seckey_verify",
+  "rustsecp256k1_v0_4_0_ec_privkey_negate",
+  "rustsecp256k1_v0_4_0_ec_pubkey_negate",
+  "rustsecp256k1_v0_4_0_ec_privkey_tweak_add",
+  "rustsecp256k1_v0_4_0_ec_seckey_tweak_mul",
+  "rustsecp256k1_v0_4_0_ec_privkey_tweak_mul",
+];
+const NOT_USED_GLOBALS = ["rustsecp256k1_v0_4_0_nonce_function_default"];
+
+const NOT_EXPORTED_FUNCTIONS = [
+  "rustsecp256k1_v0_4_0_context_preallocated_size",
+  "rustsecp256k1_v0_4_0_context_preallocated_create",
+  "rustsecp256k1_v0_4_0_context_randomize",
+  "rustsecp256k1_v0_4_0_context_no_precomp",
+  "rustsecp256k1_v0_4_0_ec_pubkey_parse",
+  "rustsecp256k1_v0_4_0_ec_pubkey_combine",
+  "rustsecp256k1_v0_4_0_ec_pubkey_serialize",
+  "rustsecp256k1_v0_4_0_ec_pubkey_tweak_add",
+  "rustsecp256k1_v0_4_0_ec_pubkey_create",
+  "rustsecp256k1_v0_4_0_ec_pubkey_tweak_mul",
+  "rustsecp256k1_v0_4_0_ec_seckey_tweak_add",
+  "rustsecp256k1_v0_4_0_ec_seckey_negate",
+  "rustsecp256k1_v0_4_0_nonce_function_rfc6979",
+  "rustsecp256k1_v0_4_0_ecdsa_sign",
+  "rustsecp256k1_v0_4_0_ecdsa_signature_serialize_compact",
+  "rustsecp256k1_v0_4_0_ecdsa_signature_parse_compact",
+  "rustsecp256k1_v0_4_0_ecdsa_signature_normalize",
+  "rustsecp256k1_v0_4_0_ecdsa_verify",
+];
+
+function strip(input) {
+  const module = binaryen.readBinary(input);
+
+  for (const name of NOT_USED_FUNCTIONS) {
+    module.removeFunction(name);
+    module.removeExport(name);
+  }
+  for (const name of NOT_USED_GLOBALS) {
+    module.removeGlobal(name);
+    module.removeExport(name);
+  }
+
+  for (const name of NOT_EXPORTED_FUNCTIONS) {
+    module.removeExport(name);
+  }
+
+  return module.emitBinary();
+}
+
+function main(location) {
+  const input = fs.readFileSync(location);
+  const output = strip(input);
+
+  const change = input.length - output.length;
+  console.log(`Size: ${input.length} -> ${output.length} (save ${change}+)`);
+
+  fs.writeFileSync(location, output);
+}
+
+main(process.argv[2]);