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Merge pull request #122 from jimpo/basic-block

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Rewrite gas metering algorithm to handle branches
This commit is contained in:
Sergei Pepyakin 2019-07-17 16:19:52 +03:00 committed by GitHub
commit 0870ce6646
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6 changed files with 567 additions and 258 deletions
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793
src/gas.rs
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@ -4,6 +4,8 @@
//! module into one that charges gas for code to be executed. See function documentation for usage
//! and details.
use std::cmp::min;
use std::mem;
use std::vec::Vec;
use parity_wasm::{elements, builder};
@ -18,9 +20,9 @@ pub fn update_call_index(instructions: &mut elements::Instructions, inserted_ind
}
}
/// A block of code represented by it's start position and cost.
///
/// The block typically starts with instructions such as `loop`, `block`, `if`, etc.
/// A control flow block is opened with the `block`, `loop`, and `if` instructions and is closed
/// with `end`. Each block implicitly defines a new label. The control blocks form a stack during
/// program execution.
///
/// An example of block:
///
@ -37,54 +39,182 @@ pub fn update_call_index(instructions: &mut elements::Instructions, inserted_ind
/// The start of the block is `i32.const 1`.
///
#[derive(Debug)]
struct BlockEntry {
struct ControlBlock {
/// The lowest control stack index corresponding to a forward jump targeted by a br, br_if, or
/// br_table instruction within this control block. The index must refer to a control block
/// that is not a loop, meaning it is a forward jump. Given the way Wasm control flow is
/// structured, the lowest index on the stack represents the furthest forward branch target.
///
/// This value will always be at most the index of the block itself, even if there is no
/// explicit br instruction targeting this control block. This does not affect how the value is
/// used in the metering algorithm.
lowest_forward_br_target: usize,
/// The active metering block that new instructions contribute a gas cost towards.
active_metered_block: MeteredBlock,
/// Whether the control block is a loop. Loops have the distinguishing feature that branches to
/// them jump to the beginning of the block, not the end as with the other control blocks.
is_loop: bool,
}
/// A block of code that metering instructions will be inserted at the beginning of. Metered blocks
/// are constructed with the property that, in the absence of any traps, either all instructions in
/// the block are executed or none are.
#[derive(Debug)]
struct MeteredBlock {
/// Index of the first instruction (aka `Opcode`) in the block.
start_pos: usize,
/// Sum of costs of all instructions until end of the block.
cost: u32,
}
/// Counter is used to manage state during the gas metering algorithm implemented by
/// `inject_counter`.
struct Counter {
/// All blocks in the order of theirs start position.
blocks: Vec<BlockEntry>,
/// A stack of control blocks. This stack grows when new control blocks are opened with
/// `block`, `loop`, and `if` and shrinks when control blocks are closed with `end`. The first
/// block on the stack corresponds to the function body, not to any labelled block. Therefore
/// the actual Wasm label index associated with each control block is 1 less than its position
/// in this stack.
stack: Vec<ControlBlock>,
// Stack of blocks. Each element is an index to a `self.blocks` vector.
stack: Vec<usize>,
/// A list of metered blocks that have been finalized, meaning they will no longer change.
finalized_blocks: Vec<MeteredBlock>,
}
impl Counter {
fn new() -> Counter {
Counter {
stack: Vec::new(),
blocks: Vec::new(),
finalized_blocks: Vec::new(),
}
}
/// Begin a new block.
fn begin(&mut self, cursor: usize) {
let block_idx = self.blocks.len();
self.blocks.push(BlockEntry {
start_pos: cursor,
cost: 1,
});
self.stack.push(block_idx);
/// Open a new control block. The cursor is the position of the first instruction in the block.
fn begin_control_block(&mut self, cursor: usize, is_loop: bool) {
let index = self.stack.len();
self.stack.push(ControlBlock {
lowest_forward_br_target: index,
active_metered_block: MeteredBlock {
start_pos: cursor,
cost: 0,
},
is_loop,
})
}
/// Finalize the current block.
/// Close the last control block. The cursor is the position of the final (pseudo-)instruction
/// in the block.
fn finalize_control_block(&mut self, cursor: usize) -> Result<(), ()> {
// This either finalizes the active metered block or merges its cost into the active
// metered block in the previous control block on the stack.
self.finalize_metered_block(cursor)?;
// Pop the control block stack.
let closing_control_block = self.stack.pop().ok_or_else(|| ())?;
let closing_control_index = self.stack.len();
if self.stack.is_empty() {
return Ok(())
}
// Update the lowest_forward_br_target for the control block now on top of the stack.
{
let control_block = self.stack.last_mut().ok_or_else(|| ())?;
control_block.lowest_forward_br_target = min(
control_block.lowest_forward_br_target,
closing_control_block.lowest_forward_br_target
);
}
// If there may have been a branch to a lower index, then also finalize the active metered
// block for the previous control block. Otherwise, finalize it and begin a new one.
let may_br_out = closing_control_block.lowest_forward_br_target < closing_control_index;
if may_br_out {
self.finalize_metered_block(cursor)?;
}
Ok(())
}
/// Finalize the current active metered block.
///
/// Finalized blocks have final cost which will not change later.
fn finalize(&mut self) -> Result<(), ()> {
self.stack.pop().ok_or_else(|| ())?;
fn finalize_metered_block(&mut self, cursor: usize) -> Result<(), ()> {
let closing_metered_block = {
let control_block = self.stack.last_mut().ok_or_else(|| ())?;
mem::replace(
&mut control_block.active_metered_block,
MeteredBlock {
start_pos: cursor + 1,
cost: 0,
}
)
};
// If the block was opened with a `block`, then its start position will be set to that of
// the active metered block in the control block one higher on the stack. This is because
// any instructions between a `block` and the first branch are part of the same basic block
// as the preceding instruction. In this case, instead of finalizing the block, merge its
// cost into the other active metered block to avoid injecting unnecessary instructions.
let last_index = self.stack.len() - 1;
if last_index > 0 {
let prev_control_block = self.stack.get_mut(last_index - 1)
.expect("last_index is greater than 0; last_index is stack size - 1; qed");
let prev_metered_block = &mut prev_control_block.active_metered_block;
if closing_metered_block.start_pos == prev_metered_block.start_pos {
prev_metered_block.cost += closing_metered_block.cost;
return Ok(())
}
}
if closing_metered_block.cost > 0 {
self.finalized_blocks.push(closing_metered_block);
}
Ok(())
}
/// Handle a branch instruction in the program. The cursor is the index of the branch
/// instruction in the program. The indices are the stack positions of the target control
/// blocks. Recall that the index is 0 for a `return` and relatively indexed from the top of
/// the stack by the label of `br`, `br_if`, and `br_table` instructions.
fn branch(&mut self, cursor: usize, indices: &[usize]) -> Result<(), ()> {
self.finalize_metered_block(cursor)?;
// Update the lowest_forward_br_target of the current control block.
for &index in indices {
let target_is_loop = {
let target_block = self.stack.get(index).ok_or_else(|| ())?;
target_block.is_loop
};
if target_is_loop {
continue;
}
let control_block = self.stack.last_mut().ok_or_else(|| ())?;
control_block.lowest_forward_br_target =
min(control_block.lowest_forward_br_target, index);
}
Ok(())
}
/// Returns the stack index of the active control block. Returns None if stack is empty.
fn active_control_block_index(&self) -> Option<usize> {
self.stack.len().checked_sub(1)
}
/// Get a reference to the currently active metered block.
fn active_metered_block(&mut self) -> Result<&mut MeteredBlock, ()> {
let top_block = self.stack.last_mut().ok_or_else(|| ())?;
Ok(&mut top_block.active_metered_block)
}
/// Increment the cost of the current block by the specified value.
fn increment(&mut self, val: u32) -> Result<(), ()> {
let stack_top = self.stack.last_mut().ok_or_else(|| ())?;
let top_block = self.blocks.get_mut(*stack_top).ok_or_else(|| ())?;
let top_block = self.active_metered_block()?;
top_block.cost = top_block.cost.checked_add(val).ok_or_else(|| ())?;
Ok(())
}
}
@ -136,56 +266,109 @@ pub fn inject_counter(
let mut counter = Counter::new();
// Begin an implicit function (i.e. `func...end`) block.
counter.begin(0);
counter.begin_control_block(0, false);
for cursor in 0..instructions.elements().len() {
let instruction = &instructions.elements()[cursor];
let instruction_cost = rules.process(instruction)?;
match *instruction {
Block(_) | If(_) | Loop(_) => {
// Increment previous block with the cost of the current opcode.
let instruction_cost = rules.process(instruction)?;
Block(_) => {
counter.increment(instruction_cost)?;
// Begin new block. The cost of the following opcodes until `End` or `Else` will
// be included into this block.
counter.begin(cursor + 1);
// Begin new block. The cost of the following opcodes until `end` or `else` will
// be included into this block. The start position is set to that of the previous
// active metered block to signal that they should be merged in order to reduce
// unnecessary metering instructions.
let top_block_start_pos = counter.active_metered_block()?.start_pos;
counter.begin_control_block(top_block_start_pos, false);
}
If(_) => {
counter.increment(instruction_cost)?;
counter.begin_control_block(cursor + 1, false);
}
Loop(_) => {
counter.increment(instruction_cost)?;
counter.begin_control_block(cursor + 1, true);
}
End => {
// Just finalize current block.
counter.finalize()?;
counter.finalize_control_block(cursor)?;
},
Else => {
// `Else` opcode is being encountered. So the case we are looking at:
//
// if
// ...
// else <-- cursor
// ...
// end
//
// Finalize the current block ('then' part of the if statement),
// and begin another one for the 'else' part.
counter.finalize()?;
counter.begin(cursor + 1);
counter.finalize_metered_block(cursor)?;
}
Br(label) | BrIf(label) => {
counter.increment(instruction_cost)?;
// Label is a relative index into the control stack.
let active_index = counter.active_control_block_index().ok_or_else(|| ())?;
let target_index = active_index.checked_sub(label as usize).ok_or_else(|| ())?;
counter.branch(cursor, &[target_index])?;
}
BrTable(ref label_vec, label_default) => {
counter.increment(instruction_cost)?;
let active_index = counter.active_control_block_index().ok_or_else(|| ())?;
let target_indices = [label_default].iter().chain(label_vec.iter())
.map(|label| active_index.checked_sub(*label as usize))
.collect::<Option<Vec<_>>>()
.ok_or_else(|| ())?;
counter.branch(cursor, &target_indices)?;
}
Return => {
counter.increment(instruction_cost)?;
counter.branch(cursor, &[0])?;
}
_ => {
// An ordinal non control flow instruction. Just increment the cost of the current block.
let instruction_cost = rules.process(instruction)?;
// An ordinal non control flow instruction increments the cost of the current block.
counter.increment(instruction_cost)?;
}
}
}
// Then insert metering calls.
let mut cumulative_offset = 0;
for block in counter.blocks {
let effective_pos = block.start_pos + cumulative_offset;
insert_metering_calls(instructions, counter.finalized_blocks, gas_func)
}
instructions.elements_mut().insert(effective_pos, I32Const(block.cost as i32));
instructions.elements_mut().insert(effective_pos+1, Call(gas_func));
// Then insert metering calls into a sequence of instructions given the block locations and costs.
fn insert_metering_calls(
instructions: &mut elements::Instructions,
mut blocks: Vec<MeteredBlock>,
gas_func: u32,
)
-> Result<(), ()>
{
use parity_wasm::elements::Instruction::*;
// Take into account these two inserted instructions.
cumulative_offset += 2;
// To do this in linear time, construct a new vector of instructions, copying over old
// instructions one by one and injecting new ones as required.
let new_instrs_len = instructions.elements().len() + 2 * blocks.len();
let original_instrs = mem::replace(
instructions.elements_mut(), Vec::with_capacity(new_instrs_len)
);
let new_instrs = instructions.elements_mut();
blocks.sort_unstable_by_key(|block| block.start_pos);
let mut block_iter = blocks.into_iter().peekable();
for (original_pos, instr) in original_instrs.into_iter().enumerate() {
// If there the next block starts at this position, inject metering instructions.
let used_block = if let Some(ref block) = block_iter.peek() {
if block.start_pos == original_pos {
new_instrs.push(I32Const(block.cost as i32));
new_instrs.push(Call(gas_func));
true
} else { false }
} else { false };
if used_block {
block_iter.next();
}
// Copy over the original instruction.
new_instrs.push(instr);
}
if block_iter.next().is_some() {
return Err(());
}
Ok(())
@ -199,17 +382,18 @@ pub fn inject_counter(
/// function is meant to keep track of the total amount of gas used and trap or otherwise halt
/// execution of the runtime if the gas usage exceeds some allowed limit.
///
/// The calls to charge gas are inserted at the beginning of every block of code. A block is
/// defined by `block`, `if`, `else`, `loop`, and `end` boundaries. Blocks form a nested hierarchy
/// where `block`, `if`, `else`, and `loop` begin a new nested block, and `end` and `else` mark the
/// end of a block. The gas cost of a block is determined statically as 1 plus the gas cost of all
/// instructions directly in that block. Each instruction is only counted in the most deeply
/// nested block containing it (ie. a block's cost does not include the cost of instructions in any
/// blocks nested within it). The cost of the `begin`, `if`, and `loop` instructions is counted
/// towards the block containing them, not the nested block that they open. There is no gas cost
/// added for `end`/`else`, as they are pseudo-instructions. The gas cost of each instruction is
/// determined by a `rules::Set` parameter. At the beginning of each block, this procedure injects
/// new instructions to call the "gas" function with the gas cost of the block as an argument.
/// The body of each function is divided into metered blocks, and the calls to charge gas are
/// inserted at the beginning of every such block of code. A metered block is defined so that,
/// unless there is a trap, either all of the instructions are executed or none are. These are
/// similar to basic blocks in a control flow graph, except that in some cases multiple basic
/// blocks can be merged into a single metered block. This is the case if any path through the
/// control flow graph containing one basic block also contains another.
///
/// Charging gas is at the beginning of each metered block ensures that 1) all instructions
/// executed are already paid for, 2) instructions that will not be executed are not charged for
/// unless execution traps, and 3) the number of calls to "gas" is minimized. The corollary is that
/// modules instrumented with this metering code may charge gas for instructions not executed in
/// the event of a trap.
///
/// Additionally, each `memory.grow` instruction found in the module is instrumented to first make
/// a call to charge gas for the additional pages requested. This cannot be done as part of the
@ -220,6 +404,8 @@ pub fn inject_counter(
/// function also rewrites all function indices references by code, table elements, etc., since
/// the addition of an imported functions changes the indices of module-defined functions.
///
/// This routine runs in time linear in the size of the input module.
///
/// The function fails if the module contains any operation forbidden by gas rule set, returning
/// the original module as an Err.
pub fn inject_gas_counter(module: elements::Module, rules: &rules::Set)
@ -304,13 +490,20 @@ mod tests {
extern crate wabt;
use parity_wasm::{serialize, builder, elements};
use parity_wasm::elements::Instruction::*;
use super::*;
use rules;
fn get_function_body(module: &elements::Module, index: usize)
-> Option<&[elements::Instruction]>
{
module.code_section()
.and_then(|code_section| code_section.bodies().get(index))
.map(|func_body| func_body.code().elements())
}
#[test]
fn simple_grow() {
use parity_wasm::elements::Instruction::*;
let module = builder::module()
.global()
.value_type().i32()
@ -332,18 +525,17 @@ mod tests {
let injected_module = inject_gas_counter(module, &rules::Set::default().with_grow_cost(10000)).unwrap();
assert_eq!(
get_function_body(&injected_module, 0).unwrap(),
&vec![
I32Const(3),
I32Const(2),
Call(0),
GetGlobal(0),
Call(2),
End
][..],
injected_module
.code_section().expect("function section should exist").bodies()[0]
.code().elements()
][..]
);
assert_eq!(
get_function_body(&injected_module, 1).unwrap(),
&vec![
GetLocal(0),
GetLocal(0),
@ -352,10 +544,7 @@ mod tests {
Call(0),
GrowMemory(0),
End,
][..],
injected_module
.code_section().expect("function section should exist").bodies()[1]
.code().elements()
][..]
);
let binary = serialize(injected_module).expect("serialization failed");
@ -364,8 +553,6 @@ mod tests {
#[test]
fn grow_no_gas_no_track() {
use parity_wasm::elements::Instruction::*;
let module = builder::module()
.global()
.value_type().i32()
@ -387,16 +574,14 @@ mod tests {
let injected_module = inject_gas_counter(module, &rules::Set::default()).unwrap();
assert_eq!(
get_function_body(&injected_module, 0).unwrap(),
&vec![
I32Const(3),
I32Const(2),
Call(0),
GetGlobal(0),
GrowMemory(0),
End
][..],
injected_module
.code_section().expect("function section should exist").bodies()[0]
.code().elements()
][..]
);
assert_eq!(injected_module.functions_space(), 2);
@ -405,154 +590,8 @@ mod tests {
self::wabt::wasm2wat(&binary).unwrap();
}
#[test]
fn simple() {
use parity_wasm::elements::Instruction::*;
let module = builder::module()
.global()
.value_type().i32()
.build()
.function()
.signature().param().i32().build()
.body()
.with_instructions(elements::Instructions::new(
vec![
GetGlobal(0),
End
]
))
.build()
.build()
.build();
let injected_module = inject_gas_counter(module, &Default::default()).unwrap();
assert_eq!(
&vec![
I32Const(2),
Call(0),
GetGlobal(0),
End
][..],
injected_module
.code_section().expect("function section should exist").bodies()[0]
.code().elements()
);
}
#[test]
fn nested() {
use parity_wasm::elements::Instruction::*;
let module = builder::module()
.global()
.value_type().i32()
.build()
.function()
.signature().param().i32().build()
.body()
.with_instructions(elements::Instructions::new(
vec![
GetGlobal(0),
Block(elements::BlockType::NoResult),
GetGlobal(0),
GetGlobal(0),
GetGlobal(0),
End,
GetGlobal(0),
End
]
))
.build()
.build()
.build();
let injected_module = inject_gas_counter(module, &Default::default()).unwrap();
assert_eq!(
&vec![
I32Const(4),
Call(0),
GetGlobal(0),
Block(elements::BlockType::NoResult),
I32Const(4),
Call(0),
GetGlobal(0),
GetGlobal(0),
GetGlobal(0),
End,
GetGlobal(0),
End
][..],
injected_module
.code_section().expect("function section should exist").bodies()[0]
.code().elements()
);
}
#[test]
fn ifelse() {
use parity_wasm::elements::Instruction::*;
let module = builder::module()
.global()
.value_type().i32()
.build()
.function()
.signature().param().i32().build()
.body()
.with_instructions(elements::Instructions::new(
vec![
GetGlobal(0),
If(elements::BlockType::NoResult),
GetGlobal(0),
GetGlobal(0),
GetGlobal(0),
Else,
GetGlobal(0),
GetGlobal(0),
End,
GetGlobal(0),
End
]
))
.build()
.build()
.build();
let injected_module = inject_gas_counter(module, &Default::default()).unwrap();
assert_eq!(
&vec![
I32Const(4),
Call(0),
GetGlobal(0),
If(elements::BlockType::NoResult),
I32Const(4),
Call(0),
GetGlobal(0),
GetGlobal(0),
GetGlobal(0),
Else,
I32Const(3),
Call(0),
GetGlobal(0),
GetGlobal(0),
End,
GetGlobal(0),
End
][..],
injected_module
.code_section().expect("function section should exist").bodies()[0]
.code().elements()
);
}
#[test]
fn call_index() {
use parity_wasm::elements::Instruction::*;
let module = builder::module()
.global()
.value_type().i32()
@ -586,36 +625,31 @@ mod tests {
let injected_module = inject_gas_counter(module, &Default::default()).unwrap();
assert_eq!(
get_function_body(&injected_module, 1).unwrap(),
&vec![
I32Const(4),
I32Const(3),
Call(0),
Call(1),
If(elements::BlockType::NoResult),
I32Const(4),
I32Const(3),
Call(0),
Call(1),
Call(1),
Call(1),
Else,
I32Const(3),
I32Const(2),
Call(0),
Call(1),
Call(1),
End,
Call(1),
End
][..],
injected_module
.code_section().expect("function section should exist").bodies()[1]
.code().elements()
][..]
);
}
#[test]
fn forbidden() {
use parity_wasm::elements::Instruction::*;
let module = builder::module()
.global()
.value_type().i32()
@ -640,4 +674,283 @@ mod tests {
}
fn parse_wat(source: &str) -> elements::Module {
let module_bytes = wabt::Wat2Wasm::new()
.validate(false)
.convert(source)
.expect("failed to parse module");
elements::deserialize_buffer(module_bytes.as_ref())
.expect("failed to parse module")
}
macro_rules! test_gas_counter_injection {
(name = $name:ident; input = $input:expr; expected = $expected:expr) => {
#[test]
fn $name() {
let input_module = parse_wat($input);
let expected_module = parse_wat($expected);
let injected_module = inject_gas_counter(input_module, &Default::default())
.expect("inject_gas_counter call failed");
let actual_func_body = get_function_body(&injected_module, 0)
.expect("injected module must have a function body");
let expected_func_body = get_function_body(&expected_module, 0)
.expect("post-module must have a function body");
assert_eq!(actual_func_body, expected_func_body);
}
}
}
test_gas_counter_injection! {
name = simple;
input = r#"
(module
(func (result i32)
(get_global 0)))
"#;
expected = r#"
(module
(func (result i32)
(call 0 (i32.const 1))
(get_global 0)))
"#
}
test_gas_counter_injection! {
name = nested;
input = r#"
(module
(func (result i32)
(get_global 0)
(block
(get_global 0)
(get_global 0)
(get_global 0))
(get_global 0)))
"#;
expected = r#"
(module
(func (result i32)
(call 0 (i32.const 6))
(get_global 0)
(block
(get_global 0)
(get_global 0)
(get_global 0))
(get_global 0)))
"#
}
test_gas_counter_injection! {
name = ifelse;
input = r#"
(module
(func (result i32)
(get_global 0)
(if
(then
(get_global 0)
(get_global 0)
(get_global 0))
(else
(get_global 0)
(get_global 0)))
(get_global 0)))
"#;
expected = r#"
(module
(func (result i32)
(call 0 (i32.const 3))
(get_global 0)
(if
(then
(call 0 (i32.const 3))
(get_global 0)
(get_global 0)
(get_global 0))
(else
(call 0 (i32.const 2))
(get_global 0)
(get_global 0)))
(get_global 0)))
"#
}
test_gas_counter_injection! {
name = branch_innermost;
input = r#"
(module
(func (result i32)
(get_global 0)
(block
(get_global 0)
(drop)
(br 0)
(get_global 0)
(drop))
(get_global 0)))
"#;
expected = r#"
(module
(func (result i32)
(call 0 (i32.const 6))
(get_global 0)
(block
(get_global 0)
(drop)
(br 0)
(call 0 (i32.const 2))
(get_global 0)
(drop))
(get_global 0)))
"#
}
test_gas_counter_injection! {
name = branch_outer_block;
input = r#"
(module
(func (result i32)
(get_global 0)
(block
(get_global 0)
(if
(then
(get_global 0)
(get_global 0)
(drop)
(br_if 1)))
(get_global 0)
(drop))
(get_global 0)))
"#;
expected = r#"
(module
(func (result i32)
(call 0 (i32.const 5))
(get_global 0)
(block
(get_global 0)
(if
(then
(call 0 (i32.const 4))
(get_global 0)
(get_global 0)
(drop)
(br_if 1)))
(call 0 (i32.const 2))
(get_global 0)
(drop))
(get_global 0)))
"#
}
test_gas_counter_injection! {
name = branch_outer_loop;
input = r#"
(module
(func (result i32)
(get_global 0)
(loop
(get_global 0)
(if
(then
(get_global 0)
(br_if 0))
(else
(get_global 0)
(get_global 0)
(drop)
(br_if 1)))
(get_global 0)
(drop))
(get_global 0)))
"#;
expected = r#"
(module
(func (result i32)
(call 0 (i32.const 3))
(get_global 0)
(loop
(call 0 (i32.const 4))
(get_global 0)
(if
(then
(call 0 (i32.const 2))
(get_global 0)
(br_if 0))
(else
(call 0 (i32.const 4))
(get_global 0)
(get_global 0)
(drop)
(br_if 1)))
(get_global 0)
(drop))
(get_global 0)))
"#
}
test_gas_counter_injection! {
name = return_from_func;
input = r#"
(module
(func (result i32)
(get_global 0)
(if
(then
(return)))
(get_global 0)))
"#;
expected = r#"
(module
(func (result i32)
(call 0 (i32.const 2))
(get_global 0)
(if
(then
(call 0 (i32.const 1))
(return)))
(call 0 (i32.const 1))
(get_global 0)))
"#
}
test_gas_counter_injection! {
name = branch_from_if_not_else;
input = r#"
(module
(func (result i32)
(get_global 0)
(block
(get_global 0)
(if
(then (br 1))
(else (br 0)))
(get_global 0)
(drop))
(get_global 0)))
"#;
expected = r#"
(module
(func (result i32)
(call 0 (i32.const 5))
(get_global 0)
(block
(get_global 0)
(if
(then
(call 0 (i32.const 1))
(br 1))
(else
(call 0 (i32.const 1))
(br 0)))
(call 0 (i32.const 2))
(get_global 0)
(drop))
(get_global 0)))
"#
}
}

6
tests/expectations/gas/branch.wat
View File

@ -4,11 +4,9 @@
(import "env" "gas" (func (;0;) (type 1)))
(func (;1;) (type 0) (result i32)
(local i32 i32)
i32.const 3
i32.const 13
call 0
block ;; label = @1
i32.const 17
call 0
i32.const 0
set_local 0
i32.const 1
@ -20,6 +18,8 @@
set_local 1
i32.const 1
br_if 0 (;@1;)
i32.const 5
call 0
get_local 0
get_local 1
tee_local 0

4
tests/expectations/gas/call.wat
View File

@ -4,7 +4,7 @@
(import "env" "gas" (func (;0;) (type 1)))
(func (;1;) (type 0) (param i32 i32) (result i32)
(local i32)
i32.const 6
i32.const 5
call 0
get_local 0
get_local 1
@ -12,7 +12,7 @@
set_local 2
get_local 2)
(func (;2;) (type 0) (param i32 i32) (result i32)
i32.const 4
i32.const 3
call 0
get_local 0
get_local 1

6
tests/expectations/gas/ifs.wat
View File

@ -3,17 +3,17 @@
(type (;1;) (func (param i32)))
(import "env" "gas" (func (;0;) (type 1)))
(func (;1;) (type 0) (param i32) (result i32)
i32.const 3
i32.const 2
call 0
i32.const 1
if (result i32) ;; label = @1
i32.const 4
i32.const 3
call 0
get_local 0
i32.const 1
i32.add
else
i32.const 3
i32.const 2
call 0
get_local 0
i32.popcnt

10
tests/expectations/gas/simple.wat
View File

@ -3,24 +3,22 @@
(type (;1;) (func (param i32)))
(import "env" "gas" (func (;0;) (type 1)))
(func (;1;) (type 0)
i32.const 3
i32.const 2
call 0
i32.const 1
if ;; label = @1
i32.const 2
i32.const 1
call 0
loop ;; label = @2
i32.const 3
i32.const 2
call 0
i32.const 123
drop
end
end)
(func (;2;) (type 0)
i32.const 2
i32.const 1
call 0
block ;; label = @1
i32.const 1
call 0
end)
(export "simple" (func 1)))

6
tests/expectations/gas/start.wat
View File

@ -6,15 +6,13 @@
(import "env" "memory" (memory (;0;) 1 1))
(import "env" "gas" (func (;1;) (type 2)))
(func (;2;) (type 1)
i32.const 5
i32.const 4
call 1
i32.const 8
i32.const 4
call 0
unreachable)
(func (;3;) (type 1)
i32.const 1
call 1)
(func (;3;) (type 1))
(export "call" (func 3))
(start 2)
(data (i32.const 8) "\01\02\03\04"))