revive: Bump PolkaVM and add static code validation (#5939)

This PR adds **static** validation that prevents upload of code that:

1) Contains basic blocks larger than the specified limit (currently
`200`)
2) Contains invalid instructions
3) Uses the `sbrk` instruction

Doing that statically at upload time (instead of at runtime) allows us
to change the basic block limit or add instructions later without
worrying about breaking old code. This is well worth the linear scan of
the whole blob on deployment in my opinion. Please note that those
checks are not applied when existing code is just run (hot path).

Also some drive by fixes:
- Remove superflous `publish = true`
- Abort fixture build on warning and fix existing warnings
- Re-enable optimizations in fixture builds (should be fixed now in
PolkaVM)
- Disable stripping for fixture builds (maybe we can get some line
information on trap via `RUST_LOG`)

---------

Co-authored-by: command-bot <>
Co-authored-by: PG Herveou <[email protected]>

prdoc/pr_5939.prdoc

@@ -0,0 +1,14 @@
+title: "[pallet-revive] Bump PolkaVM and add static code validation"
+
+doc:
+  - audience: Runtime Dev
+    description: |
+     Statically validate basic block sizes and instructions.
+
+crates:
+  - name: pallet-revive
+    bump: major
+  - name: pallet-revive-fixtures
+    bump: minor
+  - name: pallet-revive-uapi
+    bump: patch

substrate/frame/revive/Cargo.toml

@@ -19,7 +19,8 @@ targets = ["x86_64-unknown-linux-gnu"]
 [dependencies]
 environmental = { workspace = true }
 paste = { workspace = true }
-polkavm = { version = "0.11.0", default-features = false }
+polkavm = { version = "0.12.0", default-features = false }
+polkavm-common = { version = "0.12.0", default-features = false }
 bitflags = { workspace = true }
 codec = { features = [
 	"derive",
@@ -83,6 +84,7 @@ std = [
 	"pallet-revive-fixtures/std",
 	"pallet-timestamp/std",
 	"pallet-utility/std",
+	"polkavm-common/std",
 	"polkavm/std",
 	"rlp/std",
 	"scale-info/std",

substrate/frame/revive/fixtures/Cargo.toml

@@ -1,6 +1,5 @@
 [package]
 name = "pallet-revive-fixtures"
-publish = true
 version = "0.1.0"
 authors.workspace = true
 edition.workspace = true
@@ -22,7 +21,7 @@ log = { workspace = true }
 parity-wasm = { workspace = true }
 tempfile = { workspace = true }
 toml = { workspace = true }
-polkavm-linker = { version = "0.11.0" }
+polkavm-linker = { version = "0.12.0" }
 anyhow = { workspace = true, default-features = true }
 
 [features]

substrate/frame/revive/fixtures/build.rs

@@ -115,6 +115,7 @@ mod build {
 
 	fn invoke_build(current_dir: &Path) -> Result<()> {
 		let encoded_rustflags = [
+			"-Dwarnings",
 			"-Crelocation-model=pie",
 			"-Clink-arg=--emit-relocs",
 			"-Clink-arg=--export-dynamic-symbol=__polkavm_symbol_export_hack__*",
@@ -158,8 +159,8 @@ mod build {
 	/// Post-process the compiled code.
 	fn post_process(input_path: &Path, output_path: &Path) -> Result<()> {
 		let mut config = polkavm_linker::Config::default();
-		config.set_strip(true);
-		config.set_optimize(false);
+		config.set_strip(false);
+		config.set_optimize(true);
 		let orig =
 			fs::read(input_path).with_context(|| format!("Failed to read {:?}", input_path))?;
 		let linked = polkavm_linker::program_from_elf(config, orig.as_ref())

substrate/frame/revive/fixtures/build/Cargo.toml

@@ -11,7 +11,7 @@ edition = "2021"
 [dependencies]
 uapi = { package = 'pallet-revive-uapi', path = "", default-features = false }
 common = { package = 'pallet-revive-fixtures-common', path = "" }
-polkavm-derive = { version = "0.11.0" }
+polkavm-derive = { version = "0.12.0" }
 
 [profile.release]
 opt-level = 3

substrate/frame/revive/fixtures/contracts/basic_block.rs

@@ -0,0 +1,47 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Create a basic block that is larger than we allow.
+
+#![no_std]
+#![no_main]
+
+extern crate common;
+
+use core::arch::asm;
+
+// Export that is never called. We can put code here that should be in the binary
+// but is never supposed to be run.
+#[no_mangle]
+#[polkavm_derive::polkavm_export]
+pub extern "C" fn call_never() {
+	// Stores cannot be optimized away because the optimizer cannot
+	// know whether they have side effects.
+	let value: u32 = 42;
+	unsafe {
+		// Repeat 1001 times to intentionally exceed the allowed basic block limit (1000)
+		asm!(".rept 1001", "sw {x}, 0(sp)", ".endr", x = in(reg) value);
+	}
+}
+
+#[no_mangle]
+#[polkavm_derive::polkavm_export]
+pub extern "C" fn deploy() {}
+
+#[no_mangle]
+#[polkavm_derive::polkavm_export]
+pub extern "C" fn call() {}

substrate/frame/revive/fixtures/contracts/call_diverging_out_len.rs

@@ -26,7 +26,8 @@
 #![no_std]
 #![no_main]
 
-use common::input;
+extern crate common;
+
 use uapi::{HostFn, HostFnImpl as api};
 
 const BUF_SIZE: usize = 8;
@@ -36,7 +37,7 @@ static DATA: [u8; BUF_SIZE] = [1, 2, 3, 4, 5, 6, 7, 8];
 /// and expect the call output to match `expected_output`.
 fn assert_call<const N: usize>(callee_address: &[u8; 20], expected_output: [u8; BUF_SIZE]) {
 	let mut output_buf = [0u8; BUF_SIZE];
-	let mut output_buf_capped = &mut &mut output_buf[..N];
+	let output_buf_capped = &mut &mut output_buf[..N];
 
 	api::call(
 		uapi::CallFlags::ALLOW_REENTRY,
@@ -62,7 +63,7 @@ fn assert_instantiate<const N: usize>(expected_output: [u8; BUF_SIZE]) {
 	api::own_code_hash(&mut code_hash);
 
 	let mut output_buf = [0u8; BUF_SIZE];
-	let mut output_buf_capped = &mut &mut output_buf[..N];
+	let output_buf_capped = &mut &mut output_buf[..N];
 
 	api::instantiate(
 		&code_hash,

substrate/frame/revive/fixtures/contracts/call_return_code.rs

@@ -21,7 +21,7 @@
 #![no_std]
 #![no_main]
 
-use common::{input, u256_bytes};
+use common::input;
 use uapi::{HostFn, HostFnImpl as api};
 
 #[no_mangle]