[SimplifyCFG] Create attribute for fuzzing-specific optimizations.
Summary:
When building with libFuzzer, converting control flow to selects or
obscuring the original operands of CMPs reduces the effectiveness of
libFuzzer's heuristics.
This patch provides an attribute to disable or modify certain optimizations
for optimal fuzzing signal.
Provides a less aggressive alternative to https://reviews.llvm.org/D44057.
Reviewers: vitalybuka, davide, arsenm, hfinkel
Reviewed By: vitalybuka
Subscribers: junbuml, mehdi_amini, wdng, javed.absar, hiraditya, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D44232
llvm-svn: 328214
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 1c607de..d59b21d 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -1134,6 +1134,8 @@
case lltok::kw_nocf_check: B.addAttribute(Attribute::NoCfCheck); break;
case lltok::kw_norecurse: B.addAttribute(Attribute::NoRecurse); break;
case lltok::kw_nounwind: B.addAttribute(Attribute::NoUnwind); break;
+ case lltok::kw_optforfuzzing:
+ B.addAttribute(Attribute::OptForFuzzing); break;
case lltok::kw_optnone: B.addAttribute(Attribute::OptimizeNone); break;
case lltok::kw_optsize: B.addAttribute(Attribute::OptimizeForSize); break;
case lltok::kw_readnone: B.addAttribute(Attribute::ReadNone); break;
@@ -1471,6 +1473,7 @@
case lltok::kw_noreturn:
case lltok::kw_nocf_check:
case lltok::kw_nounwind:
+ case lltok::kw_optforfuzzing:
case lltok::kw_optnone:
case lltok::kw_optsize:
case lltok::kw_returns_twice:
@@ -1565,6 +1568,7 @@
case lltok::kw_noreturn:
case lltok::kw_nocf_check:
case lltok::kw_nounwind:
+ case lltok::kw_optforfuzzing:
case lltok::kw_optnone:
case lltok::kw_optsize:
case lltok::kw_returns_twice: