[libcxx-commits] [flang] [libcxx] [clang] [llvm] [libc] [compiler-rt] [msan] Intercept mallinfo2 (PR #73729)

[Vitaly Buka via libcxx-commits]

https://github.com/vitalybuka updated https://github.com/llvm/llvm-project/pull/73729

>From 0aee7158c8edf7929ba6b0d324edde21eba30093 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Tue, 28 Nov 2023 17:04:44 -0800
Subject: [PATCH 1/2] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20ch?=
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Created using spr 1.3.4

[skip ci]
---
 compiler-rt/lib/msan/msan_interceptors.cpp | 27 ++++++++++++----------
 compiler-rt/test/msan/Linux/mallinfo.cpp   |  1 -
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/compiler-rt/lib/msan/msan_interceptors.cpp b/compiler-rt/lib/msan/msan_interceptors.cpp
index bac756424e28ca7..dfecf6f7c470a6c 100644
--- a/compiler-rt/lib/msan/msan_interceptors.cpp
+++ b/compiler-rt/lib/msan/msan_interceptors.cpp
@@ -244,20 +244,23 @@ INTERCEPTOR(uptr, malloc_usable_size, void *ptr) {
 #endif
 
 #if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
-// This function actually returns a struct by value, but we can't unpoison a
-// temporary! The following is equivalent on all supported platforms but
-// aarch64 (which uses a different register for sret value).  We have a test
-// to confirm that.
-INTERCEPTOR(void, mallinfo, __sanitizer_struct_mallinfo *sret) {
-#ifdef __aarch64__
-  uptr r8;
-  asm volatile("mov %0,x8" : "=r" (r8));
-  sret = reinterpret_cast<__sanitizer_struct_mallinfo*>(r8);
-#endif
-  REAL(memset)(sret, 0, sizeof(*sret));
+
+template <class T>
+static NOINLINE void clear_mallinfo(T *sret) {
+  ENSURE_MSAN_INITED();
+  internal_memset(sret, 0, sizeof(*sret));
   __msan_unpoison(sret, sizeof(*sret));
 }
-#define MSAN_MAYBE_INTERCEPT_MALLINFO INTERCEPT_FUNCTION(mallinfo)
+
+// Interceptor relies on NRVO and assumes that sret will be pre-allocated in
+// caller frame.
+INTERCEPTOR(__sanitizer_struct_mallinfo, mallinfo) {
+  __sanitizer_struct_mallinfo sret;
+  clear_mallinfo(&sret);
+  return sret;
+}
+
+#  define MSAN_MAYBE_INTERCEPT_MALLINFO INTERCEPT_FUNCTION(mallinfo)
 #else
 #define MSAN_MAYBE_INTERCEPT_MALLINFO
 #endif
diff --git a/compiler-rt/test/msan/Linux/mallinfo.cpp b/compiler-rt/test/msan/Linux/mallinfo.cpp
index b2021c5df3cec84..3c3692969852f9b 100644
--- a/compiler-rt/test/msan/Linux/mallinfo.cpp
+++ b/compiler-rt/test/msan/Linux/mallinfo.cpp
@@ -1,5 +1,4 @@
 // RUN: %clangxx_msan -O0 -g %s -o %t && %run %t
-// UNSUPPORTED: aarch64-target-arch
 
 #include <assert.h>
 #include <malloc.h>

>From ba2ec86a29f83e2553ffc34a45028cbb5c72d1d8 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Tue, 28 Nov 2023 17:06:04 -0800
Subject: [PATCH 2/2] dedup comment

Created using spr 1.3.4
---
 compiler-rt/lib/msan/msan_interceptors.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/compiler-rt/lib/msan/msan_interceptors.cpp b/compiler-rt/lib/msan/msan_interceptors.cpp
index 680b7d397ff0622..b883c5b2a24deb6 100644
--- a/compiler-rt/lib/msan/msan_interceptors.cpp
+++ b/compiler-rt/lib/msan/msan_interceptors.cpp
@@ -252,7 +252,7 @@ static NOINLINE void clear_mallinfo(T *sret) {
   __msan_unpoison(sret, sizeof(*sret));
 }
 
-// Interceptor relies on NRVO and assumes that sret will be pre-allocated in
+// Interceptors use NRVO and assume that sret will be pre-allocated in
 // caller frame.
 INTERCEPTOR(__sanitizer_struct_mallinfo, mallinfo) {
   __sanitizer_struct_mallinfo sret;
@@ -260,8 +260,6 @@ INTERCEPTOR(__sanitizer_struct_mallinfo, mallinfo) {
   return sret;
 }
 
-// Interceptor relies on NRVO and assumes that sret will be pre-allocated in
-// caller frame.
 INTERCEPTOR(__sanitizer_struct_mallinfo2, mallinfo2) {
   __sanitizer_struct_mallinfo2 sret;
   clear_mallinfo(&sret);