From 0fd51a4554f5f4f90342f40afd35b077f6d88213 Mon Sep 17 00:00:00 2001 From: serge_sans_paille Date: Mon, 9 Sep 2019 16:59:34 +0200 Subject: Support -fstack-clash-protection for x86 Implement protection against the stack clash attack [0] through inline stack probing. Probe stack allocation every PAGE_SIZE during frame lowering or dynamic allocation to make sure the page guard, if any, is touched when touching the stack, in a similar manner to GCC[1]. This extends the existing `probe-stack' mechanism with a special value `inline-asm'. Technically the former uses function call before stack allocation while this patch provides inlined stack probes and chunk allocation. Only implemented for x86. [0] https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt [1] https://gcc.gnu.org/ml/gcc-patches/2017-07/msg00556.html This a recommit of 39f50da2a357a8f685b3540246c5d762734e035f with proper LiveIn declaration, better option handling and more portable testing. Differential Revision: https://reviews.llvm.org/D68720 --- clang/lib/Frontend/CompilerInvocation.cpp | 2 ++ 1 file changed, 2 insertions(+) (limited to 'clang/lib/Frontend/CompilerInvocation.cpp') diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index 17e1906..e57c7ef 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -1238,6 +1238,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK, Opts.NoStackArgProbe = Args.hasArg(OPT_mno_stack_arg_probe); + Opts.StackClashProtector = Args.hasArg(OPT_fstack_clash_protection); + if (Arg *A = Args.getLastArg(OPT_fobjc_dispatch_method_EQ)) { StringRef Name = A->getValue(); unsigned Method = llvm::StringSwitch(Name) -- cgit v1.1