Add conditional br count

Updates the requirements on [wasmparser](https://github.com/bytecodealliance/wasm-tools) to permit the latest version.
- [Release notes](https://github.com/bytecodealliance/wasm-tools/releases)
- [Commits](https://github.com/bytecodealliance/wasm-tools/compare/wasmparser-0.87.0...wasmparser-0.88.0)

---
updated-dependencies:
- dependency-name: wasmparser
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.toml

@@ -22,9 +22,7 @@ codegen-units = 1
 
 [dependencies]
 parity-wasm = { version = "0.45", default-features = false }
-log = { version = "0.4.8", default-features = false, optional = true }
-test-log = { version = "0.2", optional = true }
-env_logger = { version = "0.9", optional = true }
+log = "0.4"
 
 [dev-dependencies]
 binaryen = "0.12"
@@ -32,11 +30,10 @@ criterion = "0.3"
 diff = "0.1"
 rand = "0.8"
 wat = "1"
-wasmparser = "0.87"
+wasmparser = "0.88"
 wasmprinter = "0.2"
 
 [features]
 default = ["std"]
 std = ["parity-wasm/std"]
 sign_ext = ["parity-wasm/sign_ext"]
-trace-log = ["dep:log", "dep:test-log", "dep:env_logger"]

src/lib.rs

@@ -1,6 +1,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
+#[macro_use]
+extern crate log;
 
 mod export_globals;
 pub mod gas_metering;
@@ -8,6 +10,4 @@ mod stack_limiter;
 
 pub use export_globals::export_mutable_globals;
 pub use parity_wasm;
-pub use stack_limiter::{
-	compute_stack_cost, compute_stack_height_weight, inject as inject_stack_limiter,
-};
+pub use stack_limiter::{compute_stack_cost, inject as inject_stack_limiter};

src/stack_limiter/mod.rs

@@ -6,6 +6,7 @@ use parity_wasm::{
 	builder,
 	elements::{self, Instruction, Instructions, Type},
 };
+pub use max_height::StackHeightStats;
 
 /// Macro to generate preamble and postamble.
 macro_rules! instrument_call {
@@ -40,7 +41,7 @@ mod thunk;
 
 pub struct Context {
 	stack_height_global_idx: u32,
-	func_stack_costs: Vec<u32>,
+	func_stack_costs: Vec<StackHeightStats>,
 	stack_limit: u32,
 }
 
@@ -52,7 +53,11 @@ impl Context {
 
 	/// Returns `stack_cost` for `func_idx`.
 	fn stack_cost(&self, func_idx: u32) -> Option<u32> {
-		self.func_stack_costs.get(func_idx as usize).cloned()
+		if let Some(stats) = self.func_stack_costs.get(func_idx as usize) {
+			Some(stats.total_cost)
+		} else {
+			None
+		}
 	}
 
 	/// Returns stack limit specified by the rules.
@@ -154,7 +159,7 @@ fn generate_stack_height_global(module: &mut elements::Module) -> u32 {
 /// Calculate stack costs for all functions.
 ///
 /// Returns a vector with a stack cost for each function, including imports.
-pub fn compute_stack_costs(module: &elements::Module) -> Result<Vec<u32>, &'static str> {
+fn compute_stack_costs(module: &elements::Module) -> Result<Vec<StackHeightStats>, &'static str> {
 	let func_imports = module.import_count(elements::ImportCountType::Function);
 
 	// TODO: optimize!
@@ -162,7 +167,7 @@ pub fn compute_stack_costs(module: &elements::Module) -> Result<Vec<u32>, &'stat
 		.map(|func_idx| {
 			if func_idx < func_imports {
 				// We can't calculate stack_cost of the import functions.
-				Ok(0)
+				Ok(Default::default())
 			} else {
 				compute_stack_cost(func_idx as u32, module)
 			}
@@ -173,7 +178,7 @@ pub fn compute_stack_costs(module: &elements::Module) -> Result<Vec<u32>, &'stat
 /// Stack cost of the given *defined* function is the sum of it's locals count (that is,
 /// number of arguments plus number of local variables) and the maximal stack
 /// height.
-pub fn compute_stack_cost(func_idx: u32, module: &elements::Module) -> Result<u32, &'static str> {
+pub fn compute_stack_cost(func_idx: u32, module: &elements::Module) -> Result<StackHeightStats, &'static str> {
 	// To calculate the cost of a function we need to convert index from
 	// function index space to defined function spaces.
 	let func_imports = module.import_count(elements::ImportCountType::Function) as u32;
@@ -181,37 +186,6 @@ pub fn compute_stack_cost(func_idx: u32, module: &elements::Module) -> Result<u3
 		.checked_sub(func_imports)
 		.ok_or("This should be a index of a defined function")?;
 
-	let code_section =
-		module.code_section().ok_or("Due to validation code section should exists")?;
-	let body = &code_section
-		.bodies()
-		.get(defined_func_idx as usize)
-		.ok_or("Function body is out of bounds")?;
-
-	let mut locals_count: u32 = 0;
-	for local_group in body.locals() {
-		locals_count =
-			locals_count.checked_add(local_group.count()).ok_or("Overflow in local count")?;
-	}
-
-	let (max_stack_height, _max_stack_weight) = max_height::compute(defined_func_idx, module)?;
-
-	locals_count
-		.checked_add(max_stack_height)
-		.ok_or("Overflow in adding locals_count and max_stack_height")
-}
-
-/// Stack height is the measurement maximum wasm stack height reached during function execution.
-/// Stack weight is weighted value which approximates a real stack size on x64 architecture.
-pub fn compute_stack_height_weight(
-	func_idx: u32,
-	module: &elements::Module,
-) -> Result<(u32, u32), &'static str> {
-	let func_imports = module.import_count(elements::ImportCountType::Function) as u32;
-	let defined_func_idx = func_idx
-		.checked_sub(func_imports)
-		.ok_or("This should be a index of a defined function")?;
-
 	max_height::compute(defined_func_idx, module)
 }