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* Implement CFI for indirect calls via a member function pointer.Peter Collingbourne2018-06-261-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Similarly to CFI on virtual and indirect calls, this implementation tries to use program type information to make the checks as precise as possible. The basic way that it works is as follows, where `C` is the name of the class being defined or the target of a call and the function type is assumed to be `void()`. For virtual calls: - Attach type metadata to the addresses of function pointers in vtables (not the functions themselves) of type `void (B::*)()` for each `B` that is a recursive dynamic base class of `C`, including `C` itself. This type metadata has an annotation that the type is for virtual calls (to distinguish it from the non-virtual case). - At the call site, check that the computed address of the function pointer in the vtable has type `void (C::*)()`. For non-virtual calls: - Attach type metadata to each non-virtual member function whose address can be taken with a member function pointer. The type of a function in class `C` of type `void()` is each of the types `void (B::*)()` where `B` is a most-base class of `C`. A most-base class of `C` is defined as a recursive base class of `C`, including `C` itself, that does not have any bases. - At the call site, check that the function pointer has one of the types `void (B::*)()` where `B` is a most-base class of `C`. Differential Revision: https://reviews.llvm.org/D47567 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@335569 91177308-0d34-0410-b5e6-96231b3b80d8
* docs: Use the term "whole-program devirtualization" instead of "virtual ↵Peter Collingbourne2017-04-101-8/+9
| | | | | | | | | function call optimization". The former term is probably more familiar to users. Also add references to the command line flags used to enable the features described in the doc. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@299902 91177308-0d34-0410-b5e6-96231b3b80d8
* docs: Clarify that LTO visibility is based on source-level symbol visibility.Peter Collingbourne2016-05-271-8/+10
| | | | git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@271063 91177308-0d34-0410-b5e6-96231b3b80d8
* Re-apply r267784, r267824 and r267830.Peter Collingbourne2016-04-281-0/+111
| | | | | | I have updated the compiler-rt tests. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@267903 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert r267784, r267824 and r267830.Benjamin Kramer2016-04-281-111/+0
| | | | | | | | | | It makes compiler-rt tests fail if the gold plugin is enabled. Revert "Rework interface for bitset-using features to use a notion of LTO visibility." Revert "Driver: only produce CFI -fvisibility= error when compiling." Revert "clang/test/CodeGenCXX/cfi-blacklist.cpp: Exclude ms targets. They would be non-cfi." git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@267871 91177308-0d34-0410-b5e6-96231b3b80d8
* Rework interface for bitset-using features to use a notion of LTO visibility.Peter Collingbourne2016-04-271-0/+111
Bitsets, and the compiler features they rely on (vtable opt, CFI), only have visibility within the LTO'd part of the linkage unit. Therefore, only enable these features for classes with hidden LTO visibility. This notion is based on object file visibility or (on Windows) dllimport/dllexport attributes. We provide the [[clang::lto_visibility_public]] attribute to override the compiler's LTO visibility inference in cases where the class is defined in the non-LTO'd part of the linkage unit, or where the ABI supports calling classes derived from abstract base classes with hidden visibility in other linkage units (e.g. COM on Windows). If the cross-DSO CFI mode is enabled, bitset checks are emitted even for classes with public LTO visibility, as that mode uses a separate mechanism to cause bitsets to be exported. This mechanism replaces the whole-program-vtables blacklist, so remove the -fwhole-program-vtables-blacklist flag. Because __declspec(uuid()) now implies [[clang::lto_visibility_public]], the support for the special attr:uuid blacklist entry is removed. Differential Revision: http://reviews.llvm.org/D18635 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@267784 91177308-0d34-0410-b5e6-96231b3b80d8