polkavm-linker: Handle Add64 with R_RISCV_LO12_I relocation

In addition, add a test to verify the same.

Fixes: #279

Signed-off-by: Aman <[email protected]>

crates/polkavm-linker/src/program_from_elf.rs

@@ -8487,6 +8487,18 @@ where
 
                                 InstExt::Basic(BasicInst::LoadAddress { dst, target })
                             }
+                            Inst::RegImm {
+                                kind: RegImmKind::Add64,
+                                dst,
+                                src: _,
+                                imm: _,
+                            } => {
+                                let Some(dst) = cast_reg_non_zero(dst)? else {
+                                    return Err(ProgramFromElfError::other("R_RISCV_LO12_I with a zero destination register"));
+                                };
+
+                                InstExt::Basic(BasicInst::LoadAddress { dst, target })
+                            }
                             Inst::Load {
                                 kind,
                                 dst,

crates/polkavm/src/tests.rs

@@ -2866,6 +2866,22 @@ fn test_asm_reloc_add_sub(config: Config, optimize: bool, _is_64_bit: bool) {
     assert_eq!(i.instance.read_u32(address).unwrap(), 0x03030303);
 }
 
+fn test_asm_reloc_hi_lo(config: Config, optimize: bool, _is_64_bit: bool) {
+    const BLOB_64: &[u8] = include_bytes!("../../../guest-programs/asm-tests/output/reloc_hi_lo_64.elf");
+
+    let elf = BLOB_64;
+    let mut i = TestInstance::new(&config, elf, optimize);
+
+    let address = i.call::<(u32,), u32>("get_string", (0,)).unwrap();
+    assert_eq!(i.instance.read_u32(address).unwrap(), 0xA1010101);
+
+    let address = i.call::<(u32,), u32>("get_string", (1,)).unwrap();
+    assert_eq!(i.instance.read_u32(address).unwrap(), 0xB2020202);
+
+    let address = i.call::<(u32,), u32>("get_string", (2,)).unwrap();
+    assert_eq!(i.instance.read_u32(address).unwrap(), 0xC3030303);
+}
+
 fn basic_gas_metering(config: Config, gas_metering_kind: GasMeteringKind) {
     let _ = env_logger::try_init();
 
@@ -3664,6 +3680,7 @@ run_test_blob_tests! {
     test_blob_return_tuple_from_import
     test_blob_return_tuple_from_export
     test_asm_reloc_add_sub
+    test_asm_reloc_hi_lo
 }
 
 macro_rules! assert_impl {

guest-programs/asm-tests/build-asm-tests.sh

@@ -11,4 +11,5 @@ function build_asm_tests_64bit() {
 }
 
 build_asm_tests_64bit "reloc_add_sub_64"
+build_asm_tests_64bit "reloc_hi_lo_64"
 

guest-programs/asm-tests/reloc_hi_lo_64.S

@@ -0,0 +1,45 @@
+.global get_string
+
+get_string:
+    slli a0, a0, 2
+    lui a1, %hi(magic_table)
+    addi a1, a1, %lo(magic_table)
+    mv a2, a1
+    add a1, a1, a0
+    lw a0, 0(a1)
+    add a0, a0, a2
+    ret
+
+.pushsection .metadata,"",@progbits
+_get_string_name:
+    .asciz "get_string"
+_get_string_name_end:
+
+_metadata:
+    .byte 1
+    .word 0
+    .word _get_string_name_end - _get_string_name - 1
+    .quad _get_string_name
+    .byte 1
+    .byte 1
+.popsection
+
+.pushsection .polkavm_exports,"R",@note
+    .byte 1
+    .quad _metadata
+    .quad get_string
+.popsection
+
+.pushsection .rodata.secrets
+magic0: .word 0xA1010101
+magic1: .word 0xB2020202
+magic2: .word 0xC3030303
+.popsection
+
+.pushsection .rodata.table
+magic_table:
+    .word magic0 - magic_table
+    .word magic1 - magic_table
+    .word magic2 - magic_table
+.popsection
+