[Lldb-commits] [lldb] [lldb][AIX] Adding AIX version of ptrace64 (PR #120390)

[Dhruv Srivastava via lldb-commits]

https://github.com/DhruvSrivastavaX created https://github.com/llvm/llvm-project/pull/120390

This PR is in reference to porting LLDB on AIX.

Link to discussions on llvm discourse and github:

1. https://discourse.llvm.org/t/port-lldb-to-ibm-aix/80640
2. https://github.com/llvm/llvm-project/issues/101657
The complete changes for porting are present in this draft PR:
https://github.com/llvm/llvm-project/pull/102601

Adding changes for minimal build for lldb binary on AIX. 
ptrace64 is needed to debug 64-bit AIX debuggee, and its format is different than the traditional ptrace on other platforms:
https://www.ibm.com/docs/fr/aix/7.3?topic=p-ptrace-ptracex-ptrace64-subroutine

Review Request: @labath @DavidSpickett


>From 6361863d1533361146677c3bac8ce325ed2721a9 Mon Sep 17 00:00:00 2001
From: Dhruv-Srivastava <dhruv.srivastava at ibm.com>
Date: Wed, 18 Dec 2024 03:10:23 -0600
Subject: [PATCH] Added AIX version of ptrace

---
 lldb/source/Host/posix/ProcessLauncherPosixFork.cpp | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/lldb/source/Host/posix/ProcessLauncherPosixFork.cpp b/lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
index 4a9469bde2f186..0e162d04c35837 100644
--- a/lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
+++ b/lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
@@ -21,8 +21,8 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
-#include <sstream>
 #include <csignal>
+#include <sstream>
 
 #ifdef __ANDROID__
 #include <android/api-level.h>
@@ -47,8 +47,7 @@ static void write_string(int error_fd, const char *str) {
   (void)r;
 }
 
-[[noreturn]] static void ExitWithError(int error_fd,
-                                       const char *operation) {
+[[noreturn]] static void ExitWithError(int error_fd, const char *operation) {
   int err = errno;
   write_string(error_fd, operation);
   write_string(error_fd, " failed: ");
@@ -193,8 +192,13 @@ struct ForkLaunchInfo {
     }
 
     // Start tracing this child that is about to exec.
+#if !defined(_AIX)
     if (ptrace(PT_TRACE_ME, 0, nullptr, 0) == -1)
       ExitWithError(error_fd, "ptrace");
+#else
+    if (ptrace64(PT_TRACE_ME, 0, 0, 0, nullptr) == -1)
+      ExitWithError(error_fd, "ptrace");
+#endif
   }
 
   // Execute.  We should never return...