Summary:
This change generalizes the implicit null checks pass to work with
instructions that don't have any explicit register defs. This lets us
use X86's `cmp` against memory as faulting load instructions.
Reviewers: reames, JosephTremoulet
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11286
llvm-svn: 242703
Summary:
Before this change ImplicitNullChecks would only pick loads of the form:
```
test Reg, Reg
jz elsewhere
fallthrough:
movl 32(Reg), Reg2
```
but not (say)
```
test Reg, Reg
jz elsewhere
fallthrough:
inc Reg3
movl 32(Reg), Reg2
```
This change teaches ImplicitNullChecks to look through "unrelated"
instructions like `inc Reg3` when searching for a load instruction
to convert to a trapping load.
Reviewers: atrick, JosephTremoulet, reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11044
llvm-svn: 241850
Summary:
This change introduces a !make.implicit metadata that allows the
frontend to pre-select the set of explicit null checks that will be
considered for transformation into implicit null checks.
The reason for not using profiling data instead of !make.implicit is
explained in the change to `FaultMaps.rst`.
Reviewers: atrick, reames, pgavlin, JosephTremoulet
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10824
llvm-svn: 241116
Summary:
The parser is exercised by llvm-objdump using -print-fault-maps. As is
probably obvious, the code itself was "heavily inspired" by
http://reviews.llvm.org/D10434.
Reviewers: reames, atrick, JosephTremoulet
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10491
llvm-svn: 240304
Sanjoy Das