From 3f0a77e78816682c67bbc3294095e4d31afda252 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?kleines=20Filmr=C3=B6llchen?= <filmroellchen@serenityos.org>
Date: Tue, 17 Oct 2023 19:05:27 +0200
Subject: [PATCH] disasm: Allow disassembling just one symbol

This is done in a crude way for now in that we
disassemble all instructions up to the symbol without printing them.
---
 Userland/Utilities/disasm.cpp | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/Userland/Utilities/disasm.cpp b/Userland/Utilities/disasm.cpp
index 97125cb006..b8684a05e7 100644
--- a/Userland/Utilities/disasm.cpp
+++ b/Userland/Utilities/disasm.cpp
@@ -41,12 +41,14 @@ struct Symbol {
 ErrorOr<int> serenity_main(Main::Arguments args)
 {
     StringView path {};
+    StringView target_symbol;
 
     Core::ArgsParser args_parser;
     args_parser.set_general_help(
         "Disassemble an executable, and show human-readable "
         "assembly code for each function.");
-    args_parser.add_positional_argument(path, "Path to i386 binary file", "path");
+    args_parser.add_positional_argument(path, "Path to binary file", "path");
+    args_parser.add_option(target_symbol, "Show disassembly only for a specific symbol", "symbol", 's', "symbol");
     args_parser.parse(args);
 
     OwnPtr<Core::MappedFile> file;
@@ -120,6 +122,7 @@ ErrorOr<int> serenity_main(Main::Arguments args)
     Vector<Symbol>::Iterator current_zero_size_symbol = zero_size_symbols.begin();
     bool is_first_symbol = true;
     bool current_instruction_is_in_symbol = false;
+    bool found_symbol = false;
 
     for (;;) {
         auto offset = stream.offset();
@@ -182,6 +185,16 @@ ErrorOr<int> serenity_main(Main::Arguments args)
             is_first_symbol = false;
         }
 
+        // Past the target symbol now; no need to disassemble more.
+        if (found_symbol && current_ranged_symbol->name != target_symbol)
+            break;
+
+        found_symbol = !target_symbol.is_empty() && current_ranged_symbol->name == target_symbol;
+
+        // We have not found the target symbol yet; don't print anything.
+        if (!target_symbol.is_empty() && current_ranged_symbol->name != target_symbol)
+            continue;
+
         // Insert extra newline after the "dangling" symbols.
         if (needs_separator)
             outln();