From 1fa3a6ded252d7c1c0ff974a4fcd1af67a1577cf Mon Sep 17 00:00:00 2001
From: andrewjcg <andrewjcg@meta.com>
Date: Fri, 1 Nov 2024 19:31:00 -0400
Subject: [PATCH] Don't include undefined symbols in symbol index (#629)

Don't count undefined symbols in the index of symbols that py-spy builds.
This can causes e.g. py-spy to misattribute an undefined ref to `_PyRuntime`
in some location other than `libpython.so` as the definition.
---
 src/binary_parser.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/binary_parser.rs b/src/binary_parser.rs
index 4df02687..cd1317f1 100644
--- a/src/binary_parser.rs
+++ b/src/binary_parser.rs
@@ -185,6 +185,10 @@ pub fn parse_binary(filename: &Path, addr: u64, size: u64) -> Result<BinaryInfo,
             }
 
             for sym in elf.syms.iter() {
+                // Skip undefined symbols.
+                if sym.st_shndx == goblin::elf::section_header::SHN_UNDEF as usize {
+                    continue;
+                }
                 // Skip imported symbols
                 if sym.is_import()
                     || (bss_end != 0
@@ -203,6 +207,10 @@ pub fn parse_binary(filename: &Path, addr: u64, size: u64) -> Result<BinaryInfo,
                 }
             }
             for dynsym in elf.dynsyms.iter() {
+                // Skip undefined symbols.
+                if dynsym.st_shndx == goblin::elf::section_header::SHN_UNDEF as usize {
+                    continue;
+                }
                 // Skip imported symbols
                 if dynsym.is_import()
                     || (bss_end != 0