[clang][UBSan] Sanitization for alignment assumptions.
authorRoman Lebedev <lebedev.ri@gmail.com>
Tue, 15 Jan 2019 09:44:25 +0000 (09:44 +0000)
committerRoman Lebedev <lebedev.ri@gmail.com>
Tue, 15 Jan 2019 09:44:25 +0000 (09:44 +0000)
commitbd1c0870198e025f92d31eead0fb2019c4057a4a
tree2a4a6f0f4a9bcf4c75401d2fac214510e98ca255
parent6d0413fe237f444fc83ec6e433b50fb1908a3c18
[clang][UBSan] Sanitization for alignment assumptions.

Summary:
UB isn't nice. It's cool and powerful, but not nice.
Having a way to detect it is nice though.
[[ https://wg21.link/p1007r3 | P1007R3: std::assume_aligned ]] / http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1007r2.pdf says:
```
We propose to add this functionality via a library function instead of a core language attribute.
...
If the pointer passed in is not aligned to at least N bytes, calling assume_aligned results in undefined behaviour.
```

This differential teaches clang to sanitize all the various variants of this assume-aligned attribute.

Requires D54588 for LLVM IRBuilder changes.
The compiler-rt part is D54590.

This is a second commit, the original one was r351105,
which was mass-reverted in r351159 because 2 compiler-rt tests were failing.

Reviewers: ABataev, craig.topper, vsk, rsmith, rnk, #sanitizers, erichkeane, filcab, rjmccall

Reviewed By: rjmccall

Subscribers: chandlerc, ldionne, EricWF, mclow.lists, cfe-commits, bkramer

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54589

llvm-svn: 351177
19 files changed:
clang/docs/ReleaseNotes.rst
clang/docs/UndefinedBehaviorSanitizer.rst
clang/lib/CodeGen/CGBuiltin.cpp
clang/lib/CodeGen/CGCall.cpp
clang/lib/CodeGen/CGExprScalar.cpp
clang/lib/CodeGen/CGStmtOpenMP.cpp
clang/lib/CodeGen/CodeGenFunction.cpp
clang/lib/CodeGen/CodeGenFunction.h
clang/test/CodeGen/catch-alignment-assumption-attribute-align_value-on-lvalue.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-attribute-align_value-on-paramvar.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-attribute-alloc_align-on-function-variable.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-attribute-alloc_align-on-function.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-attribute-assume_aligned-on-function-two-params.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-attribute-assume_aligned-on-function.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-blacklist.c [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-builtin_assume_aligned-three-params-variable.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-builtin_assume_aligned-three-params.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-builtin_assume_aligned-two-params.cpp [new file with mode: 0644]
clang/test/CodeGen/catch-alignment-assumption-openmp.cpp [new file with mode: 0644]