[1/1] object lifetime instrumentation for Valgrind [PR66487]

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 68410a86af..4db18387c1 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1506,6 +1506,7 @@  OBJS = \
 	gimple-ssa-warn-restrict.o \
 	gimple-streamer-in.o \
 	gimple-streamer-out.o \
+	gimple-valgrind-interop.o \
 	gimple-walk.o \
 	gimple-warn-recursion.o \
 	gimplify.o \
diff --git a/gcc/builtins.def b/gcc/builtins.def
index f03df32f98..b05e20e062 100644
--- a/gcc/builtins.def
+++ b/gcc/builtins.def
@@ -1194,6 +1194,9 @@  DEF_GCC_BUILTIN (BUILT_IN_LINE, "LINE", BT_FN_INT, ATTR_NOTHROW_LEAF_LIST)
 /* Control Flow Redundancy hardening out-of-line checker.  */
 DEF_BUILTIN_STUB (BUILT_IN___HARDCFR_CHECK, "__builtin___hardcfr_check")
 
+/* Wrappers for Valgrind client requests.  */
+DEF_EXT_LIB_BUILTIN (BUILT_IN_VALGRIND_MAKE_UNDEFINED, "__gcc_vgmc_make_mem_undefined", BT_FN_VOID_PTR_SIZE, ATTR_NOTHROW_LEAF_LIST)
+
 /* Synchronization Primitives.  */
 #include "sync-builtins.def"
 
diff --git a/gcc/common.opt b/gcc/common.opt
index f070aff8cb..b53565fc1a 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -3372,6 +3372,10 @@  Enum(auto_init_type) String(pattern) Value(AUTO_INIT_PATTERN)
 EnumValue
 Enum(auto_init_type) String(zero) Value(AUTO_INIT_ZERO)
 
+fvalgrind-annotations
+Common Var(flag_valgrind_annotations) Optimization
+Annotate lifetime boundaries with Valgrind client requests.
+
 ; -fverbose-asm causes extra commentary information to be produced in
 ; the generated assembly code (to make it more readable).  This option
 ; is generally only of use to those who actually need to read the
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index c1128d9274..aaf0213bbf 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -1567,6 +1567,11 @@  Disable TM clone registry in libgcc. It is enabled in libgcc by default.
 This option helps to reduce code size for embedded targets which do
 not use transactional memory.
 
+@item --enable-valgrind-interop
+Provide wrappers for Valgrind client requests in libgcc, which are used for
+@option{-fvalgrind-annotations}.  Requires Valgrind header files for the
+target (in the build-time sysroot if building a cross-compiler).
+
 @item --with-cpu=@var{cpu}
 @itemx --with-cpu-32=@var{cpu}
 @itemx --with-cpu-64=@var{cpu}
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 32f535e1ed..6befe7aa22 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -657,6 +657,7 @@  Objective-C and Objective-C++ Dialects}.
 -fno-stack-limit  -fsplit-stack
 -fstrub=disable  -fstrub=strict  -fstrub=relaxed
 -fstrub=all  -fstrub=at-calls  -fstrub=internal
+-fvalgrind-annotations
 -fvtable-verify=@r{[}std@r{|}preinit@r{|}none@r{]}
 -fvtv-counts  -fvtv-debug
 -finstrument-functions  -finstrument-functions-once
@@ -12920,6 +12921,9 @@  can use @option{-flifetime-dse=1}.  The default behavior can be
 explicitly selected with @option{-flifetime-dse=2}.
 @option{-flifetime-dse=0} is equivalent to @option{-fno-lifetime-dse}.
 
+See @option{-fvalgrind-annotations} for instrumentation that allows to
+detect violations of standard lifetime semantics using Valgrind.
+
 @opindex flive-range-shrinkage
 @item -flive-range-shrinkage
 Attempt to decrease register pressure through register live range
@@ -17976,6 +17980,29 @@  function attributes that tell which mode was selected for each function.
 The primary use of this option is for testing, to exercise thoroughly
 the @code{strub} machinery.
 
+@opindex fvalgrind-annotations
+@item -fvalgrind-annotations
+Emit Valgrind client requests annotating object lifetime boundaries.
+This allows to detect attempts to access fields of a C++ object after
+its destructor has completed (but storage was not deallocated yet), or
+to initialize it in advance from @code{operator new} rather than the
+constructor.
+
+This instrumentation relies on presence of @code{__gcc_vgmc_make_mem_undefined}
+function that wraps the corresponding Valgrind client request. It is provided
+by libgcc when it is configured with @samp{--enable-valgrind-interop}.
+Otherwise, you can implement it like this:
+
+@smallexample
+#include <valgrind/memcheck.h>
+
+void
+__gcc_vgmc_make_mem_undefined (void *addr, size_t size)
+@{
+  VALGRIND_MAKE_MEM_UNDEFINED (addr, size);
+@}
+@end smallexample
+
 @opindex fvtable-verify
 @item -fvtable-verify=@r{[}std@r{|}preinit@r{|}none@r{]}
 This option is only available when compiling C++ code.
diff --git a/gcc/gimple-valgrind-interop.cc b/gcc/gimple-valgrind-interop.cc
new file mode 100644
index 0000000000..839b1dd0ba
--- /dev/null
+++ b/gcc/gimple-valgrind-interop.cc
@@ -0,0 +1,112 @@ 
+/* Annotate lifetime boundaries for Valgrind.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 3, or (at your option) any
+later version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tree.h"
+#include "function.h"
+#include "cfg.h"
+#include "basic-block.h"
+#include "gimple.h"
+#include "gimple-iterator.h"
+#include "tree-pass.h"
+#include "gimplify-me.h"
+#include "fold-const.h"
+
+namespace {
+
+/* Emit VALGRIND_MAKE_MEM_UNDEFINED annotation for the object given by VAR.  */
+
+bool
+annotate_undef (gimple_stmt_iterator *gsi, tree var)
+{
+  tree size = arg_size_in_bytes (TREE_TYPE (var));
+  if (size == size_zero_node)
+    return false;
+
+  tree addr = build_fold_addr_expr (var);
+  tree decl = builtin_decl_explicit (BUILT_IN_VALGRIND_MAKE_UNDEFINED);
+  tree call = build_call_expr (decl, 2, addr, size);
+
+  force_gimple_operand_gsi (gsi, call, false, NULL_TREE, false, GSI_NEW_STMT);
+  return true;
+}
+
+const pass_data pass_data_instrument_valgrind = {
+  GIMPLE_PASS, /* type */
+  "valgrind",  /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  TV_NONE, /* tv_id */
+  PROP_cfg, /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  0, /* todo_flags_finish */
+};
+
+}
+
+class pass_instrument_valgrind : public gimple_opt_pass
+{
+public:
+  pass_instrument_valgrind (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_instrument_valgrind, ctxt)
+  {
+  }
+
+  unsigned int execute (function *) final override;
+  bool gate (function *) final override;
+};
+
+bool
+pass_instrument_valgrind::gate (function *)
+{
+  return flag_valgrind_annotations;
+}
+
+/* Scan for GIMPLE clobbers that mark object lifetime boundaries and
+   make them known to Valgrind by emitting corresponding client requests.  */
+
+unsigned int
+pass_instrument_valgrind::execute (function *fun)
+{
+  bool changed = false;
+  basic_block bb;
+  FOR_EACH_BB_FN (bb, fun)
+    {
+      for (gimple_stmt_iterator gsi = gsi_start_nondebug_bb (bb);
+	   !gsi_end_p (gsi); gsi_next_nondebug (&gsi))
+	{
+	  gimple *stmt = gsi_stmt (gsi);
+
+	  /* Leave CLOBBER_EOLs for ASan.  */
+	  if (gimple_clobber_p (stmt, CLOBBER_UNDEF))
+	    changed |= annotate_undef (&gsi, gimple_assign_lhs (stmt));
+	}
+    }
+
+  return changed ? TODO_update_ssa : 0;
+}
+
+gimple_opt_pass *
+make_pass_instrument_valgrind (gcc::context *ctxt)
+{
+  return new pass_instrument_valgrind (ctxt);
+}
diff --git a/gcc/passes.def b/gcc/passes.def
index d3fccdf0a4..dade93135c 100644
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -57,6 +57,7 @@  along with GCC; see the file COPYING3.  If not see
   PUSH_INSERT_PASSES_WITHIN (pass_build_ssa_passes)
       NEXT_PASS (pass_fixup_cfg);
       NEXT_PASS (pass_build_ssa);
+      NEXT_PASS (pass_instrument_valgrind);
       NEXT_PASS (pass_walloca, /*strict_mode_p=*/true);
       NEXT_PASS (pass_warn_printf);
       NEXT_PASS (pass_warn_nonnull_compare);
diff --git a/gcc/testsuite/g++.dg/valgrind-annotations-1.C b/gcc/testsuite/g++.dg/valgrind-annotations-1.C
new file mode 100644
index 0000000000..49dc5a9cf1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/valgrind-annotations-1.C
@@ -0,0 +1,22 @@ 
+/* { dg-do compile { target c++11 } } */
+/* { dg-options "-O2 -fvalgrind-annotations -fdump-tree-optimized" } */
+
+#include <new>
+
+struct Foo
+{
+  int val;
+};
+
+struct Bar : Foo
+{
+  Bar() {}
+};
+
+int main ()
+{
+  alignas(Bar) char buf [sizeof (Bar)];
+  Bar *obj = new(buf) Bar;
+}
+
+/* { dg-final { scan-tree-dump-times "__builtin___gcc_vgmc_make_mem_undefined" 1 "optimized" } } */
diff --git a/gcc/testsuite/g++.dg/valgrind-annotations-2.C b/gcc/testsuite/g++.dg/valgrind-annotations-2.C
new file mode 100644
index 0000000000..a8b646d076
--- /dev/null
+++ b/gcc/testsuite/g++.dg/valgrind-annotations-2.C
@@ -0,0 +1,12 @@ 
+/* { dg-do compile { target c++11 } } */
+/* { dg-options "-O2 -fvalgrind-annotations -fdump-tree-optimized" } */
+
+struct Foo
+{
+  char buf [1024];
+  Foo () {}
+};
+
+Foo Obj;
+
+/* { dg-final { scan-tree-dump-times "__builtin___gcc_vgmc_make_mem_undefined" 1 "optimized" } } */
diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
index de2820b3a3..2a9bf1f60f 100644
--- a/gcc/tree-pass.h
+++ b/gcc/tree-pass.h
@@ -440,6 +440,7 @@  extern gimple_opt_pass *make_pass_omp_device_lower (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_object_sizes (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_early_object_sizes (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_warn_access (gcc::context *ctxt);
+extern gimple_opt_pass *make_pass_instrument_valgrind (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_warn_printf (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_warn_recursion (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_strlen (gcc::context *ctxt);
diff --git a/libgcc/Makefile.in b/libgcc/Makefile.in
index d8163c5af9..bb1e8d773c 100644
--- a/libgcc/Makefile.in
+++ b/libgcc/Makefile.in
@@ -436,6 +436,9 @@  LIB2ADD += $(srcdir)/hardcfr.c
 # Stack scrubbing infrastructure.
 LIB2ADD += $(srcdir)/strub.c
 
+# Wrappers for Valgrind client requests.
+LIB2ADD += $(srcdir)/valgrind-interop.c
+
 # While emutls.c has nothing to do with EH, it is in LIB2ADDEH*
 # instead of LIB2ADD because that's the way to be sure on some targets
 # (e.g. *-*-darwin*) only one copy of it is linked.
diff --git a/libgcc/config.in b/libgcc/config.in
index f93c64a00c..19ad450680 100644
--- a/libgcc/config.in
+++ b/libgcc/config.in
@@ -3,6 +3,9 @@ 
 /* Define to the .hidden-like directive if it exists. */
 #undef AS_HIDDEN_DIRECTIVE
 
+/* Build Valgrind request wrappers */
+#undef ENABLE_VALGRIND_INTEROP
+
 /* Define to 1 if the assembler supports AVX. */
 #undef HAVE_AS_AVX
 
@@ -61,6 +64,9 @@ 
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
+/* Define to 1 if you have the <valgrind/memcheck.h> header file. */
+#undef HAVE_VALGRIND_MEMCHECK_H
+
 /* Define to the address where bug reports for this package should be sent. */
 #undef PACKAGE_BUGREPORT
 
diff --git a/libgcc/configure b/libgcc/configure
index cf14920965..580fda0cca 100755
--- a/libgcc/configure
+++ b/libgcc/configure
@@ -715,6 +715,7 @@  with_system_libunwind
 enable_cet
 enable_explicit_exception_frame_registration
 enable_tm_clone_registry
+enable_valgrind_interop
 with_glibc_version
 enable_tls
 with_gcc_major_version_only
@@ -1359,6 +1360,8 @@  Optional Features:
                           start, for use e.g. for compatibility with
                           installations without PT_GNU_EH_FRAME support
   --disable-tm-clone-registry    disable TM clone registry
+  --enable-valgrind-interop
+                          build wrappers for Valgrind client requests
   --enable-tls            Use thread-local storage [default=yes]
 
 Optional Packages:
@@ -4466,7 +4469,8 @@  as_fn_arith $ac_cv_sizeof_long_double \* 8 && long_double_type_size=$as_val
 
 for ac_header in inttypes.h stdint.h stdlib.h ftw.h \
 	unistd.h sys/stat.h sys/types.h \
-	string.h strings.h memory.h sys/auxv.h sys/mman.h
+	string.h strings.h memory.h sys/auxv.h sys/mman.h \
+	valgrind/memcheck.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_preproc "$LINENO" "$ac_header" "$as_ac_Header"
@@ -5024,6 +5028,22 @@  fi
 
 
 
+# Check whether --enable-valgrind-interop was given.
+if test "${enable_valgrind_interop+set}" = set; then :
+  enableval=$enable_valgrind_interop;
+else
+  enable_valgrind_interop=no
+fi
+
+if test $enable_valgrind_interop != no; then
+  if test $ac_cv_header_valgrind_memcheck_h = no; then
+    as_fn_error $? "--enable-valgrind-interop: valgrind/memcheck.h not found" "$LINENO" 5
+  fi
+
+$as_echo "#define ENABLE_VALGRIND_INTEROP 1" >>confdefs.h
+
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking if the linker ($LD) is GNU ld" >&5
 $as_echo_n "checking if the linker ($LD) is GNU ld... " >&6; }
 if ${acl_cv_prog_gnu_ld+:} false; then :
diff --git a/libgcc/configure.ac b/libgcc/configure.ac
index 2fc9d5d7c9..23289a81aa 100644
--- a/libgcc/configure.ac
+++ b/libgcc/configure.ac
@@ -231,7 +231,8 @@  AC_SUBST(long_double_type_size)
 
 AC_CHECK_HEADERS(inttypes.h stdint.h stdlib.h ftw.h \
 	unistd.h sys/stat.h sys/types.h \
-	string.h strings.h memory.h sys/auxv.h sys/mman.h)
+	string.h strings.h memory.h sys/auxv.h sys/mman.h \
+	valgrind/memcheck.h)
 AC_HEADER_STDC
 
 # Check for decimal float support.
@@ -303,6 +304,18 @@  esac
 ])
 AC_SUBST([use_tm_clone_registry])
 
+AC_ARG_ENABLE([valgrind-interop],
+              [AC_HELP_STRING([--enable-valgrind-interop],
+                              [build wrappers for Valgrind client requests])],
+              [],
+              [enable_valgrind_interop=no])
+if test $enable_valgrind_interop != no; then
+  if test $ac_cv_header_valgrind_memcheck_h = no; then
+    AC_MSG_ERROR([--enable-valgrind-interop: valgrind/memcheck.h not found])
+  fi
+  AC_DEFINE(ENABLE_VALGRIND_INTEROP, 1, [Build Valgrind request wrappers])
+fi
+
 AC_LIB_PROG_LD_GNU
 
 AC_MSG_CHECKING([for thread model used by GCC])
diff --git a/libgcc/libgcc2.h b/libgcc/libgcc2.h
index 750670e8ca..ee4500adc1 100644
--- a/libgcc/libgcc2.h
+++ b/libgcc/libgcc2.h
@@ -558,6 +558,8 @@  extern void __strub_enter (void **);
 extern void __strub_update (void**);
 extern void __strub_leave (void **);
 
+extern void __gcc_vgmc_make_mem_undefined (void *, size_t);
+
 #ifndef HIDE_EXPORTS
 #pragma GCC visibility pop
 #endif
diff --git a/libgcc/valgrind-interop.c b/libgcc/valgrind-interop.c
new file mode 100644
index 0000000000..fdb8d41bc5
--- /dev/null
+++ b/libgcc/valgrind-interop.c
@@ -0,0 +1,40 @@ 
+/* Wrappers for Valgrind client requests.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#include "tsystem.h"
+#include "auto-target.h"
+
+#ifdef ENABLE_VALGRIND_INTEROP
+
+#include <valgrind/memcheck.h>
+
+/* Externally callable wrapper for Valgrind Memcheck client request:
+   declare SIZE bytes of memory at address ADDR as uninitialized.  */
+
+void
+__gcc_vgmc_make_mem_undefined (void *addr, size_t size)
+{
+  VALGRIND_MAKE_MEM_UNDEFINED (addr, size);
+}
+#endif