the gas limit opcode (#139)

Signed-off-by: xermicus <cyrill@parity.io>

Cargo.toml

@@ -68,7 +68,7 @@ git2 = "0.19.0"
 # polkadot-sdk and friends
 codec = { version = "3.6.12", default-features = false, package = "parity-scale-codec" }
 scale-info = { version = "2.11.1", default-features = false }
-polkadot-sdk = { git = "https://github.com/paritytech/polkadot-sdk", rev = "53f6473c9c8c9d18b5ef0ed02a587757495d1dbf" }
+polkadot-sdk = { git = "https://github.com/paritytech/polkadot-sdk", rev = "ddfc608962febad82f154dc1ec39768d6675b329" }
 
 # llvm
 [workspace.dependencies.inkwell]

crates/integration/contracts/GasLimit.sol

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8;
+
+/* runner.json
+{
+    "differential": false,
+    "actions": [
+        {
+            "Instantiate": {
+                "code": {
+                    "Solidity": {
+                        "contract": "GasLimit"
+                    }
+                }
+            }
+        },
+        {
+            "VerifyCall": {
+                "success": true
+            }
+        }
+    ]
+}
+*/
+
+contract GasLimit {
+    constructor() payable {
+        assert(block.gaslimit == 2000000000000);
+    }
+}

crates/integration/src/tests.rs

@@ -48,6 +48,7 @@ test_spec!(block_hash, "BlockHash", "BlockHash.sol");
 test_spec!(delegate, "Delegate", "Delegate.sol");
 test_spec!(gas_price, "GasPrice", "GasPrice.sol");
 test_spec!(gas_left, "GasLeft", "GasLeft.sol");
+test_spec!(gas_limit, "GasLimit", "GasLimit.sol");
 
 fn instantiate(path: &str, contract: &str) -> Vec<SpecsAction> {
     vec![Instantiate {

crates/llvm-context/src/polkavm/evm/context.rs

@@ -7,12 +7,20 @@ use crate::polkavm::Dependency;
 
 /// Translates the `gas_limit` instruction.
 pub fn gas_limit<'ctx, D>(
-    _context: &mut Context<'ctx, D>,
+    context: &mut Context<'ctx, D>,
 ) -> anyhow::Result<inkwell::values::BasicValueEnum<'ctx>>
 where
     D: Dependency + Clone,
 {
-    todo!()
+    let gas_limit_value = context
+        .build_runtime_call(revive_runtime_api::polkavm_imports::GAS_LIMIT, &[])
+        .expect("the gas_limit syscall method should return a value")
+        .into_int_value();
+
+    Ok(context
+        .builder()
+        .build_int_z_extend(gas_limit_value, context.word_type(), "gas_limit")?
+        .into())
 }
 
 /// Translates the `gas_price` instruction.

crates/runner/src/runtime.rs

@@ -1,4 +1,4 @@
-use frame_support::runtime;
+use frame_support::{runtime, weights::constants::WEIGHT_REF_TIME_PER_SECOND};
 
 use pallet_revive::AccountId32Mapper;
 use polkadot_sdk::*;
@@ -46,6 +46,7 @@ mod runtime {
 #[derive_impl(frame_system::config_preludes::SolochainDefaultConfig)]
 impl frame_system::Config for Runtime {
     type Block = Block;
+    type BlockWeights = BlockWeights;
     type AccountId = AccountId32;
     type AccountData = pallet_balances::AccountData<<Runtime as pallet_balances::Config>::Balance>;
 }
@@ -65,6 +66,10 @@ parameter_types! {
     pub const DepositPerByte: Balance = 1;
     pub const DepositPerItem: Balance = 2;
     pub const CodeHashLockupDepositPercent: Perbill = Perbill::from_percent(0);
+    pub BlockWeights: frame_system::limits::BlockWeights =
+        frame_system::limits::BlockWeights::simple_max(
+            Weight::from_parts(2u64 * WEIGHT_REF_TIME_PER_SECOND, u64::MAX),
+        );
 }
 
 #[derive_impl(pallet_revive::config_preludes::TestDefaultConfig)]

crates/runtime-api/src/polkavm_imports.c

@@ -94,6 +94,8 @@ POLKAVM_IMPORT(void, code_hash, uint32_t, uint32_t)
 
 POLKAVM_IMPORT(void, deposit_event, uint32_t, uint32_t, uint32_t, uint32_t)
 
+POLKAVM_IMPORT(uint64_t, gas_limit);
+
 POLKAVM_IMPORT(void, get_immutable_data, uint32_t, uint32_t);
 
 POLKAVM_IMPORT(uint64_t, get_storage, uint32_t, uint32_t, uint32_t, uint32_t, uint32_t)

crates/runtime-api/src/polkavm_imports.rs

@@ -44,6 +44,8 @@ pub static CODE_HASH: &str = "code_hash";
 
 pub static DEPOSIT_EVENT: &str = "deposit_event";
 
+pub static GAS_LIMIT: &str = "gas_limit";
+
 pub static GET_IMMUTABLE_DATA: &str = "get_immutable_data";
 
 pub static GET_STORAGE: &str = "get_storage";
@@ -74,7 +76,7 @@ pub static WEIGHT_TO_FEE: &str = "weight_to_fee";
 
 /// All imported runtime API symbols.
 /// Useful for configuring common attributes and linkage.
-pub static IMPORTS: [&str; 31] = [
+pub static IMPORTS: [&str; 32] = [
     SBRK,
     MEMORY_SIZE,
     ADDRESS,
@@ -92,6 +94,7 @@ pub static IMPORTS: [&str; 31] = [
     CODE_SIZE,
     CODE_HASH,
     DEPOSIT_EVENT,
+    GAS_LIMIT,
     GET_IMMUTABLE_DATA,
     GET_STORAGE,
     HASH_KECCAK_256,