[msan] Remove more attributes from sanitized functions.

Summary:
MSan instrumentation adds stores and loads even to pure
readonly/writeonly functions. It is removing some of those attributes
from instrumented functions and call targets, but apparently not enough.

Remove writeonly, argmemonly and speculatable in addition to readonly /
readnone.

Reviewers: pcc, vitalybuka

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69541

1 files changed, 8 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 69c9020e060..2c82dbd9060 100644
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -3278,7 +3278,10 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
         // Clear out readonly/readnone attributes.
         AttrBuilder B;
         B.addAttribute(Attribute::ReadOnly)
-          .addAttribute(Attribute::ReadNone);
+            .addAttribute(Attribute::ReadNone)
+            .addAttribute(Attribute::WriteOnly)
+            .addAttribute(Attribute::ArgMemOnly)
+            .addAttribute(Attribute::Speculatable);
         Func->removeAttributes(AttributeList::FunctionIndex, B);
       }
 
@@ -4595,7 +4598,10 @@ bool MemorySanitizer::sanitizeFunction(Function &F, TargetLibraryInfo &TLI) {
   // Clear out readonly/readnone attributes.
   AttrBuilder B;
   B.addAttribute(Attribute::ReadOnly)
-    .addAttribute(Attribute::ReadNone);
+      .addAttribute(Attribute::ReadNone)
+      .addAttribute(Attribute::WriteOnly)
+      .addAttribute(Attribute::ArgMemOnly)
+      .addAttribute(Attribute::Speculatable);
   F.removeAttributes(AttributeList::FunctionIndex, B);
 
   return Visitor.runOnFunction();