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Differential D69541

[msan] Remove more attributes from sanitized functions.
ClosedPublic

Authored by eugenis on Oct 28 2019, 5:53 PM.

Details

Reviewers
pcc
vitalybuka
Commits
rG03e882050f1a: [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.

Diff Detail

Event Timeline

eugenis created this revision.Oct 28 2019, 5:53 PM
Herald added a project: Restricted Project. · View Herald TranscriptOct 28 2019, 5:53 PM
Herald added a subscriber: hiraditya. · View Herald Transcript
Harbormaster completed remote builds in B40171: Diff 226822.Oct 28 2019, 5:53 PM
vitalybuka accepted this revision.Oct 28 2019, 5:55 PM
This revision is now accepted and ready to land.Oct 28 2019, 5:55 PM
Closed by commit rG03e882050f1a: [msan] Remove more attributes from sanitized functions. (authored by eugenis). · Explain WhyOct 28 2019, 5:57 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
llvm/
lib/
Transforms/
Instrumentation/
10 lines
test/
Instrumentation/
MemorySanitizer/
47 lines

Diff 226822

llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

Show First 20 Lines • Show All 3,272 Lines • ▼ Show 20 Lines if (CS.isCall()) {
// We are going to insert code that relies on the fact that the callee // We are going to insert code that relies on the fact that the callee
// will become a non-readonly function after it is instrumented by us. To // will become a non-readonly function after it is instrumented by us. To
// prevent this code from being optimized out, mark that function // prevent this code from being optimized out, mark that function
// non-readonly in advance. // non-readonly in advance.
if (Function *Func = Call->getCalledFunction()) { if (Function *Func = Call->getCalledFunction()) {
// Clear out readonly/readnone attributes. // Clear out readonly/readnone attributes.
AttrBuilder B; AttrBuilder B;
B.addAttribute(Attribute::ReadOnly) B.addAttribute(Attribute::ReadOnly)
.addAttribute(Attribute::ReadNone); .addAttribute(Attribute::ReadNone)
.addAttribute(Attribute::WriteOnly)
.addAttribute(Attribute::ArgMemOnly)
.addAttribute(Attribute::Speculatable);
Func->removeAttributes(AttributeList::FunctionIndex, B); Func->removeAttributes(AttributeList::FunctionIndex, B);
} }
maybeMarkSanitizerLibraryCallNoBuiltin(Call, TLI); maybeMarkSanitizerLibraryCallNoBuiltin(Call, TLI);
} }
IRBuilder<> IRB(&I); IRBuilder<> IRB(&I);
unsigned ArgOffset = 0; unsigned ArgOffset = 0;
▲ Show 20 Lines • Show All 1,300 Lines • ▼ Show 20 Linesbool MemorySanitizer::sanitizeFunction(Function &F, TargetLibraryInfo &TLI) {
if (!CompileKernel && F.getName() == kMsanModuleCtorName) if (!CompileKernel && F.getName() == kMsanModuleCtorName)
return false; return false;
MemorySanitizerVisitor Visitor(F, *this, TLI); MemorySanitizerVisitor Visitor(F, *this, TLI);
// Clear out readonly/readnone attributes. // Clear out readonly/readnone attributes.
AttrBuilder B; AttrBuilder B;
B.addAttribute(Attribute::ReadOnly) B.addAttribute(Attribute::ReadOnly)
.addAttribute(Attribute::ReadNone); .addAttribute(Attribute::ReadNone)
.addAttribute(Attribute::WriteOnly)
.addAttribute(Attribute::ArgMemOnly)
.addAttribute(Attribute::Speculatable);
F.removeAttributes(AttributeList::FunctionIndex, B); F.removeAttributes(AttributeList::FunctionIndex, B);
return Visitor.runOnFunction(); return Visitor.runOnFunction();
} }

llvm/test/Instrumentation/MemorySanitizer/attributes.ll

  • This file was added.
; RUN: opt < %s -S -passes='module(msan-module),function(msan)' 2>&1 | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
declare void @a_() sanitize_memory readnone
declare void @b_() sanitize_memory readonly
declare void @c_() sanitize_memory writeonly
declare void @d_(i32* %p) sanitize_memory writeonly argmemonly
declare void @e_() sanitize_memory speculatable
define void @a() sanitize_memory readnone {
entry:
call void @a_()
ret void
}
define void @b() sanitize_memory readonly {
entry:
call void @b_()
ret void
}
define void @c() sanitize_memory writeonly {
entry:
call void @c_()
ret void
}
define void @d(i32* %p) sanitize_memory writeonly argmemonly {
entry:
call void @d_(i32* %p)
ret void
}
define void @e() sanitize_memory speculatable {
entry:
call void @e_()
ret void
}
; CHECK-NOT: readnone
; CHECK-NOT: readonly
; CHECK-NOT: writeonly
; CHECK-NOT: argmemonly
; CHECK-NOT: speculatable