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| author | serge_sans_paille <sguelton@redhat.com> | 2019-09-09 16:59:34 +0200 |
|---|---|---|
| committer | serge-sans-paille <sguelton@redhat.com> | 2020-02-08 13:31:52 +0100 |
| commit | e229017732bcf1911210903ee9811033d5588e0d (patch) | |
| tree | 39e5edcfd4d07fc0f1096d80f6b3c3974ca3e021 /clang/lib/CodeGen/CodeGenModule.cpp | |
| parent | ef83d46b6b428fa1c8614cd28ab6fe3f07f8d075 (diff) | |
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 better option
handling and more portable testing
Differential Revision: https://reviews.llvm.org/D68720
Diffstat (limited to 'clang/lib/CodeGen/CodeGenModule.cpp')
| -rw-r--r-- | clang/lib/CodeGen/CodeGenModule.cpp | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index 4e730025ac4f..235a40501afc 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -1514,6 +1514,9 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, if (CodeGenOpts.UnwindTables) B.addAttribute(llvm::Attribute::UWTable); + if (CodeGenOpts.StackClashProtector) + B.addAttribute("probe-stack", "inline-asm"); + if (!hasUnwindExceptions(LangOpts)) B.addAttribute(llvm::Attribute::NoUnwind); |