[lldb] fix step in AArch64 trampoline (#90783)

Detects AArch64 trampolines in order to be able to step in a function
through a trampoline on AArch64.

---------

Co-authored-by: Vincent Belliard <v-bulle@github.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
index 16f6d2e..1646ee9 100644
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -2356,13 +2356,30 @@ unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
     bool symbol_size_valid =
         symbol.st_size != 0 || symbol.getType() != STT_FUNC;
 
+    bool is_trampoline = false;
+    if (arch.IsValid() && (arch.GetMachine() == llvm::Triple::aarch64)) {
+      // On AArch64, trampolines are registered as code.
+      // If we detect a trampoline (which starts with __AArch64ADRPThunk_ or
+      // __AArch64AbsLongThunk_) we register the symbol as a trampoline. This
+      // way we will be able to detect the trampoline when we step in a function
+      // and step through the trampoline.
+      if (symbol_type == eSymbolTypeCode) {
+        llvm::StringRef trampoline_name = mangled.GetName().GetStringRef();
+        if (trampoline_name.starts_with("__AArch64ADRPThunk_") ||
+            trampoline_name.starts_with("__AArch64AbsLongThunk_")) {
+          symbol_type = eSymbolTypeTrampoline;
+          is_trampoline = true;
+        }
+      }
+    }
+
     Symbol dc_symbol(
         i + start_id, // ID is the original symbol table index.
         mangled,
         symbol_type,                    // Type of this symbol
         is_global,                      // Is this globally visible?
         false,                          // Is this symbol debug info?
-        false,                          // Is this symbol a trampoline?
+        is_trampoline,                  // Is this symbol a trampoline?
         false,                          // Is this symbol artificial?
         AddressRange(symbol_section_sp, // Section in which this symbol is
                                         // defined or null.