[Openmp-commits] [openmp] [OpenMP][AIX] Implement __kmp_is_address_mapped() for AIX (PR #90516)

[Xing Xue via Openmp-commits]

https://github.com/xingxue-ibm created https://github.com/llvm/llvm-project/pull/90516

This patch implements `__kmp_is_address_mapped()` for AIX by calling `loadquery()` to get the load info of the process and then checking if the address falls within the range of the data segment of one of the loaded modules.

>From 580c791da657c29246d447d39b002b635e7a120f Mon Sep 17 00:00:00 2001
From: Xing Xue <xingxue at outlook.com>
Date: Mon, 29 Apr 2024 15:36:51 -0400
Subject: [PATCH] Implement __kmp_is_address_mapped() for AIX.

---
 openmp/runtime/src/z_Linux_util.cpp | 49 ++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 4 deletions(-)

diff --git a/openmp/runtime/src/z_Linux_util.cpp b/openmp/runtime/src/z_Linux_util.cpp
index 11ce083f4801d3..affb577a539367 100644
--- a/openmp/runtime/src/z_Linux_util.cpp
+++ b/openmp/runtime/src/z_Linux_util.cpp
@@ -29,7 +29,9 @@
 #include <semaphore.h>
 #endif // KMP_OS_LINUX
 #include <sys/resource.h>
-#if !KMP_OS_AIX
+#if KMP_OS_AIX
+#include <sys/ldr.h>
+#else
 #include <sys/syscall.h>
 #endif
 #include <sys/time.h>
@@ -2338,9 +2340,48 @@ int __kmp_is_address_mapped(void *addr) {
   found = (int)addr < (__builtin_wasm_memory_size(0) * PAGESIZE);
 #elif KMP_OS_AIX
 
-  (void)rc;
-  // FIXME(AIX): Implement this
-  found = 1;
+  uint32_t loadQueryBufSize = 4096u; // Default loadquery buffer size.
+  char *loadQueryBuf;
+
+  for (;;) {
+    loadQueryBuf = (char *)KMP_INTERNAL_MALLOC(loadQueryBufSize);
+    if (loadQueryBuf == NULL) {
+      return 0;
+    }
+
+    rc = loadquery(L_GETXINFO | L_IGNOREUNLOAD, loadQueryBuf, loadQueryBufSize);
+    if (rc < 0) {
+      KMP_INTERNAL_FREE(loadQueryBuf);
+      if (errno != ENOMEM) {
+        return 0;
+      }
+      // errno == ENOMEM; double the size.
+      loadQueryBufSize <<= 1;
+      continue;
+    }
+    // Obtained the load info successfully.
+    break;
+  }
+
+  struct ld_xinfo *curLdInfo = (struct ld_xinfo *)loadQueryBuf;
+
+  // Loop through the load info to find if there is a match.
+  for (;;) {
+    uintptr_t curDataStart = (uintptr_t)curLdInfo->ldinfo_dataorg;
+    uintptr_t curDataEnd = curDataStart + curLdInfo->ldinfo_datasize;
+
+    // The data segment is readable and writable.
+    if (curDataStart <= (uintptr_t)addr && (uintptr_t)addr < curDataEnd) {
+      found = 1;
+      break;
+    }
+    if (curLdInfo->ldinfo_next == 0u) {
+      // Reached the end of load info.
+      break;
+    }
+    curLdInfo = (struct ld_xinfo *)((char *)curLdInfo + curLdInfo->ldinfo_next);
+  }
+  KMP_INTERNAL_FREE(loadQueryBuf);
 
 #else