From b0d0b6a2b2201be16e5b0bed101f3e7691b8165c Mon Sep 17 00:00:00 2001
From: Nikita Smith <git.nikita.smith@gmail.com>
Date: Mon, 2 Feb 2026 21:39:05 -0800
Subject: [PATCH] factor out LEB128 writer

---
 src/dwarf/dwarf.c      | 39 +++++++++++++++++++++++++++++++++++++++
 src/dwarf/dwarf.h      |  5 +++++
 src/dwarf/dwarf_expr.c | 29 ++---------------------------
 3 files changed, 46 insertions(+), 27 deletions(-)

diff --git a/src/dwarf/dwarf.c b/src/dwarf/dwarf.c
index feeaa924..9e768ba1 100644
--- a/src/dwarf/dwarf.c
+++ b/src/dwarf/dwarf.c
@@ -827,3 +827,42 @@ dw_string_from_cfa_opcode(DW_CFA_Opcode opcode)
   }
   return str8_zero();
 }
+
+internal String8
+dw_write_uleb128(Arena *arena, U64 v)
+{
+  U64 buffer_size = 0;
+  U8  buffer[10];
+  U64 value = v;
+  do {
+    U8 byte = value & 0x7f;
+    value >>= 7;
+    if (value != 0) {
+      byte |= 0x80;
+    }
+    Assert(buffer_size < sizeof(buffer));
+    buffer[buffer_size++] = byte;
+  } while (value > 0);
+  return str8_copy(arena, str8(buffer, buffer_size));
+}
+
+internal String8
+dw_write_sleb128(Arena *arena, S64 v)
+{
+  U64 buffer_size = 0;
+  U8  buffer[10];
+  for (S64 value = v, more = 1; more != 0; ) {
+    U8 byte = value & 0x7f;
+    value >>= 7;
+    U8 sign_bit = byte & 0x40;
+    if ((value == 0 && sign_bit == 0) || (value == -1 && sign_bit != 0)) {
+      more = 0;
+    } else {
+      byte |= 0x80;
+    }
+    Assert(buffer_size < sizeof(buffer));
+    buffer[buffer_size++] = byte;
+  }
+  return str8_copy(arena, str8(buffer, buffer_size));
+}
+
diff --git a/src/dwarf/dwarf.h b/src/dwarf/dwarf.h
index a098e521..2b540976 100644
--- a/src/dwarf/dwarf.h
+++ b/src/dwarf/dwarf.h
@@ -1778,4 +1778,9 @@ internal String8 dw_string_from_rng_list_entry_kind(Arena *arena, DW_RLE kind);
 internal String8 dw_string_from_register(Arena *arena, Arch arch, U64 reg_id);
 internal String8 dw_string_from_cfa_opcode(DW_CFA_Opcode opcode);
 
+////////////////////////////////
+
+internal String8 dw_write_uleb128(Arena *arena, U64 v);
+internal String8 dw_write_sleb128(Arena *arena, S64 v);
+
 #endif // DWARF_H
diff --git a/src/dwarf/dwarf_expr.c b/src/dwarf/dwarf_expr.c
index 359fb41f..5d73e1c2 100644
--- a/src/dwarf/dwarf_expr.c
+++ b/src/dwarf/dwarf_expr.c
@@ -1611,35 +1611,10 @@ dw_encode_expr(Arena *arena, Arch arch, DW_Format format, DW_ExprEnc *encs, U64
       str8_serial_push_struct(scratch.arena, srl, &e->s64);
     } break;
     case DW_ExprEncType_ULEB128: {
-      U64 buffer_size = 0;
-      U8  buffer[10];
-      for (U64 value = e->u64; value != 0; ) {
-        U8 byte = value & 0x7f;
-        value >>= 7;
-        if (value != 0) {
-          byte |= 0x80;
-        }
-        Assert(buffer_size < sizeof(buffer));
-        buffer[buffer_size++] = byte;
-      }
-      str8_serial_push_string(scratch.arena, srl, str8(buffer, buffer_size));
+      str8_serial_push_string(scratch.arena, srl, dw_write_uleb128(scratch.arena, e->u64));
     } break;
     case DW_ExprEncType_SLEB128: {
-      U64 buffer_size = 0;
-      U8  buffer[10];
-      for (S64 value = e->s64, more = 1; more != 0; ) {
-        U8 byte = value & 0x7f;
-        value >>= 7;
-        U8 sign_bit = byte & 0x40;
-        if ((value == 0 && sign_bit == 0) || (value == -1 && sign_bit != 0)) {
-          more = 0;
-        } else {
-          byte |= 0x80;
-        }
-        Assert(buffer_size < sizeof(buffer));
-        buffer[buffer_size++] = byte;
-      }
-      str8_serial_push_string(scratch.arena, srl, str8(buffer, buffer_size));
+      str8_serial_push_string(scratch.arena, srl, dw_write_sleb128(scratch.arena, e->s64));
     } break;
     case DW_ExprEncType_Addr: {
       U64 addr_size = byte_size_from_arch(arch);