Add recognition for another x86 epilogue sequence (ret followed by
a nop). Fixes an instruction stepping problem when trying to step
over the final instructions of an epilogue.
<rdar://problem/18068877>
llvm-svn: 221241
diff --git a/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp b/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
index 32a21d2..d6f8f24 100644
--- a/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
+++ b/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
@@ -804,6 +804,12 @@
// [ 0xc3 ] ret
// [ 0xe8 xx xx xx xx ] call __stack_chk_fail (this is sometimes the final insn in the function)
+ // or
+
+ // [ 0x5d ] mov %rbp, %rsp (aka pop %rbp)
+ // [ 0xc3 ] ret
+ // [ 0x0f 0x1f 0x44 xx xx ] nopl (%rax,%rax) (aka nop)
+
// We want to add a Row describing how to unwind when we're stopped on the 'ret' instruction where the
// CFA is no longer defined in terms of rbp, but is now defined in terms of rsp like on function entry.
// (or the 'jmp' instruction in the second case)
@@ -834,6 +840,11 @@
{
ret_insn_offset = m_func_bounds.GetByteSize() - 6;
}
+ else if (bytebuf[0] == 0x5d && bytebuf[1] == 0xc3
+ && bytebuf[2] == 0x0f && bytebuf[3] == 0x1f & bytebuf[4] == 0x44) // mov & ret & nop
+ {
+ ret_insn_offset = m_func_bounds.GetByteSize() - 6;
+ }
}
}
else if (m_func_bounds.GetByteSize() > 2)