Make disassembler output more readable (#215)

solana-labs · Sep 17, 2021 · c3dd337 · c3dd337
1 parent d0b0a16
commit c3dd337
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Showing 2 changed files with 36 additions and 3 deletions.
diff --git a/src/disassembler.rs b/src/disassembler.rs
@@ -45,19 +45,46 @@ fn byteswap_str(name: &str, insn: &ebpf::Insn) -> String {
     format!("{}{} r{}", name, insn.imm, insn.dst)
 }
 
+#[inline]
+fn signed_off_str(value: i16) -> String {
+    if value < 0 {
+        format!("-{:#x}", -value)
+    } else {
+        format!("+{:#x}", value)
+    }
+}
+
 #[inline]
 fn ld_st_imm_str(name: &str, insn: &ebpf::Insn) -> String {
-    format!("{} [r{}+{:#x}], {}", name, insn.dst, insn.off, insn.imm)
+    format!(
+        "{} [r{}{}], {}",
+        name,
+        insn.dst,
+        signed_off_str(insn.off),
+        insn.imm
+    )
 }
 
 #[inline]
 fn ld_reg_str(name: &str, insn: &ebpf::Insn) -> String {
-    format!("{} r{}, [r{}+{:#x}]", name, insn.dst, insn.src, insn.off)
+    format!(
+        "{} r{}, [r{}{}]",
+        name,
+        insn.dst,
+        insn.src,
+        signed_off_str(insn.off)
+    )
 }
 
 #[inline]
 fn st_reg_str(name: &str, insn: &ebpf::Insn) -> String {
-    format!("{} [r{}+{:#x}], r{}", name, insn.dst, insn.off, insn.src)
+    format!(
+        "{} [r{}{}], r{}",
+        name,
+        insn.dst,
+        signed_off_str(insn.off),
+        insn.src
+    )
 }
 
 #[inline]

diff --git a/tests/disassembler.rs b/tests/disassembler.rs
@@ -60,18 +60,21 @@ fn test_neg64() {
 #[test]
 fn test_ldxw() {
     disasm!("entrypoint:\n    ldxw r1, [r2+0x5]\n");
+    disasm!("entrypoint:\n    ldxw r1, [r2-0x5]\n");
 }
 
 // Example for InstructionType::StoreImm.
 #[test]
 fn test_stw() {
     disasm!("entrypoint:\n    stw [r2+0x5], 7\n");
+    disasm!("entrypoint:\n    stw [r2-0x5], 7\n");
 }
 
 // Example for InstructionType::StoreReg.
 #[test]
 fn test_stxw() {
     disasm!("entrypoint:\n    stxw [r2+0x5], r8\n");
+    disasm!("entrypoint:\n    stxw [r2-0x5], r8\n");
 }
 
 // Example for InstructionType::JumpUnconditional.
@@ -147,18 +150,21 @@ fn test_ldindw() {
 #[test]
 fn test_ldxdw() {
     disasm!("entrypoint:\n    ldxdw r1, [r2+0x3]\n");
+    disasm!("entrypoint:\n    ldxdw r1, [r2-0x3]\n");
 }
 
 // Example for InstructionType::StoreImm.
 #[test]
 fn test_sth() {
     disasm!("entrypoint:\n    sth [r1+0x2], 3\n");
+    disasm!("entrypoint:\n    sth [r1-0x2], 3\n");
 }
 
 // Example for InstructionType::StoreReg.
 #[test]
 fn test_stxh() {
     disasm!("entrypoint:\n    stxh [r1+0x2], r3\n");
+    disasm!("entrypoint:\n    stxh [r1-0x2], r3\n");
 }
 
 // Test all supported AluBinary mnemonics.