Support block.number for soroban target.

src/codegen/mod.rs

@@ -141,6 +141,7 @@ pub enum HostFunctions {
     StringNewFromLinearMemory,
     StrKeyToAddr,
     GetLedgerTimestamp,
+    GetLedgerSequence,
     GetCurrentContractAddress,
     BytesNewFromLinearMemory,
     BytesLen,
@@ -189,6 +190,7 @@ impl HostFunctions {
             HostFunctions::VecPushBack => "v.6",
             HostFunctions::StringNewFromLinearMemory => "b.i",
             HostFunctions::StrKeyToAddr => "a.1",
+            HostFunctions::GetLedgerSequence => "x.3",
             HostFunctions::GetLedgerTimestamp => "x.4",
             HostFunctions::GetCurrentContractAddress => "x.7",
             HostFunctions::BytesNewFromLinearMemory => "b.3",

src/emit/soroban/mod.rs

@@ -118,6 +118,7 @@ impl HostFunctions {
                 .fn_type(&[ty.into(), ty.into()], false),
             HostFunctions::StrKeyToAddr => bin.context.i64_type().fn_type(&[ty.into()], false),
             HostFunctions::GetLedgerTimestamp => bin.context.i64_type().fn_type(&[], false),
+            HostFunctions::GetLedgerSequence => bin.context.i64_type().fn_type(&[], false),
             HostFunctions::GetCurrentContractAddress => bin.context.i64_type().fn_type(&[], false),
             HostFunctions::ObjToI128Lo64 => bin.context.i64_type().fn_type(&[ty.into()], false),
             HostFunctions::ObjToI128Hi64 => bin.context.i64_type().fn_type(&[ty.into()], false),
@@ -467,6 +468,7 @@ impl SorobanTarget {
             HostFunctions::StringNewFromLinearMemory,
             HostFunctions::StrKeyToAddr,
             HostFunctions::GetLedgerTimestamp,
+            HostFunctions::GetLedgerSequence,
             HostFunctions::GetCurrentContractAddress,
             HostFunctions::BytesNewFromLinearMemory,
             HostFunctions::BytesCopyToLinearMemory,

src/emit/soroban/target.rs

@@ -1063,6 +1063,36 @@ impl<'a> TargetRuntime<'a> for SorobanTarget {
 
                 value.into()
             }
+            Expression::Builtin {
+                loc,
+                tys,
+                kind: Builtin::BlockNumber,
+                args,
+            } => {
+                let function_name = HostFunctions::GetLedgerSequence.name();
+                let function_value =
+                    runtime_helper(bin, function_name, "reading Soroban ledger sequence number/block.number");
+
+                let u32_val = bin
+                    .builder
+                    .build_call(function_value, &[], function_name)
+                    .unwrap()
+                    .try_as_basic_value()
+                    .left()
+                    .unwrap()
+                    .into_int_value();
+
+                return bin
+                    .builder
+                    .build_right_shift(
+                        u32_val,
+                        bin.context.i64_type().const_int(32, false),
+                        false,
+                        "block",
+                    )
+                    .unwrap()
+                    .into();
+            }
             _ => unsupported_soroban(expr.loc(), "this Soroban builtin"),
         }
     }

tests/soroban_testcases/block_number.rs

@@ -0,0 +1,25 @@
+use crate::build_solidity;
+use soroban_sdk::testutils::Ledger;
+use soroban_sdk::{FromVal, Val};
+
+#[test]
+fn get_ledger_sequence() {
+    let runtime = build_solidity(
+        r#"
+        contract LedgerSequence {
+            function get_ledger_sequence() public view returns (uint64) {
+                return block.number;
+            }
+        }
+        "#,
+        |_| {},
+    );
+    let addr = runtime.contracts.last().unwrap();
+    let samples: Vec<u64> = vec![1, 99, 2, 33, 13, 9, 15, 10001, 2 << 16, 2 << 24];
+    for number in samples {
+        runtime.env.ledger().set_sequence_number(number as u32);
+        let block_number_val: Val = runtime.invoke_contract(addr, "get_ledger_sequence", vec![]);
+        let block_number_u64: u64 = FromVal::from_val(&runtime.env, &block_number_val);
+        assert_eq!(number, block_number_u64);
+    }
+}

tests/soroban_testcases/mod.rs

@@ -3,6 +3,7 @@ mod alloc;
 mod array_args;
 mod atomic_swap;
 mod auth;
+mod block_number;
 mod constructor;
 mod cross_contract_calls;
 mod events;