Commit Graph

3 Commits

Author SHA1 Message Date
Hans Wennborg
960a40ec57 Re-commit r301040 "X86: Don't emit zero-byte functions on Windows"
In addition to the original commit, tighten the condition for when to
pad empty functions to COFF Windows.  This avoids running into problems
when targeting e.g. Win32 AMDGPU, which caused test failures when this
was committed initially.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301047 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-21 21:48:41 +00:00
Hans Wennborg
0720f631bf Revert r301040 "X86: Don't emit zero-byte functions on Windows"
This broke almost all bots. Reverting while fixing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301041 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-21 21:10:37 +00:00
Hans Wennborg
fe76aaa6ee X86: Don't emit zero-byte functions on Windows
Empty functions can lead to duplicate entries in the Guard CF Function
Table of a binary due to multiple functions sharing the same RVA,
causing the kernel to refuse to load that binary.

We had a terrific bug due to this in Chromium.

It turns out we were already doing this for Mach-O in certain
situations. This patch expands the code for that in
AsmPrinter::EmitFunctionBody() and renames
TargetInstrInfo::getNoopForMachoTarget() to simply getNoop() since it
seems it was used for not just Mach-O anyway.

Differential Revision: https://reviews.llvm.org/D32330

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301040 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-21 20:58:12 +00:00