Rename AllVRegsAllocated to NoVRegs. This avoids the connotation of
running after register and simply describes that no vregs are used in
a machine function. With that we can simply compute the property and do
not need to dump/parse it in .mir files.
Differential Revision: http://reviews.llvm.org/D23850
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279698 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r278048. Something changed between the last time I
built this--it takes awhile on my ridiculously slow and ancient
computer--and now that broke this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278053 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Based on two patches by Michael Mueller.
This is a target attribute that causes a function marked with it to be
emitted as "hotpatchable". This particular mechanism was originally
devised by Microsoft for patching their binaries (which they are
constantly updating to stay ahead of crackers, script kiddies, and other
ne'er-do-wells on the Internet), but is now commonly abused by Windows
programs to hook API functions.
This mechanism is target-specific. For x86, a two-byte no-op instruction
is emitted at the function's entry point; the entry point must be
immediately preceded by 64 (32-bit) or 128 (64-bit) bytes of padding.
This padding is where the patch code is written. The two byte no-op is
then overwritten with a short jump into this code. The no-op is usually
a `movl %edi, %edi` instruction; this is used as a magic value
indicating that this is a hotpatchable function.
Reviewers: majnemer, sanjoy, rnk
Subscribers: dberris, llvm-commits
Differential Revision: https://reviews.llvm.org/D19908
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278048 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The `"patchable-function"` attribute can be used by an LLVM client to
influence LLVM's code generation in ways that makes the generated code
easily patchable at runtime (for instance, to redirect control).
Right now only one patchability scheme is supported,
`"prologue-short-redirect"`, but this can be expanded in the future.
Reviewers: joker.eph, rnk, echristo, dberris
Subscribers: joker.eph, echristo, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D19046
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266715 91177308-0d34-0410-b5e6-96231b3b80d8
