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Catch invalid uses of {must,no}_preserve_cheri_tag #648

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Catch invalid uses of {must,no}_preserve_cheri_tag #648

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b119b16
Catch invalid uses of {must,no}_preserve_cheri_tags
arichardson Apr 25, 2022
6830144
Delete a stale broken test
arichardson Oct 5, 2022
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10 changes: 7 additions & 3 deletions llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -298,9 +298,13 @@ bool TargetLowering::findOptimalMemOpLowering(
}

// If we are preserving capabilities, the first VT must be a capability
if (Op.PreserveTags == PreserveCheriTags::Required && MemOps.empty() &&
!VT.isFatPointer()) {
return false;
if (Op.PreserveTags == PreserveCheriTags::Required && MemOps.empty()) {
assert(cheriCapabilityType().isValid());
assert(Size >= cheriCapabilityType().getStoreSize().getFixedSize() &&
"PreserveCheriTags::Required should not be possible for copies of "
"less than capability size");
if (!VT.isFatPointer())
return false;
}

MemOps.push_back(VT);
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7 changes: 7 additions & 0 deletions llvm/lib/IR/IntrinsicInst.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -557,6 +557,13 @@ void llvm::setPreserveCheriTags(IntrinsicInst *I, PreserveCheriTags NewValue,
assert(DL.hasCheriCapabilities());
assert(!I->hasFnAttr(Attribute::NoPreserveCheriTags) &&
"attempting to set conflicting attributes");
#ifndef NDEBUG
if (auto MTI = dyn_cast<AnyMemTransferInst>(I))
if (auto *Length = dyn_cast<ConstantInt>(MTI->getLength()))
assert(Length->getZExtValue() >= DL.getMaxPointerSize() &&
"must_preserve_cheri_tags cannot be set on copies of less than "
"capability size");
#endif
I->addAttribute(llvm::AttributeList::FunctionIndex,
llvm::Attribute::MustPreserveCheriTags);
NumMustPreserveTagAttrs++;
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21 changes: 21 additions & 0 deletions llvm/lib/IR/Verifier.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2000,6 +2000,13 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
"Attribute 'jumptable' requires 'unnamed_addr'", V);
}

if (Attrs.hasFnAttribute(Attribute::NoPreserveCheriTags))
Assert(DL.hasCheriCapabilities(),
"Attribute 'no_preserve_cheri_tags' requires a CHERI target", V);
if (Attrs.hasFnAttribute(Attribute::MustPreserveCheriTags))
Assert(DL.hasCheriCapabilities(),
"Attribute 'must_preserve_cheri_tags' requires a CHERI target", V);

if (Attrs.hasFnAttribute(Attribute::AllocSize)) {
std::pair<unsigned, Optional<unsigned>> Args =
Attrs.getAllocSizeArgs(AttributeList::FunctionIndex);
Expand Down Expand Up @@ -4706,6 +4713,20 @@ void Verifier::visitIntrinsicCall(Intrinsic::ID ID, CallBase &Call) {
Assert(IsValidAlignment(MTI->getSourceAlignment()),
"alignment of arg 1 of memory intrinsic must be 0 or a power of 2",
Call);
if (DL.hasCheriCapabilities() &&
MTI->shouldPreserveCheriTags() == PreserveCheriTags::Required)
if (auto *Length = dyn_cast<ConstantInt>(MTI->getLength()))
Assert(Length->getZExtValue() >= DL.getMaxPointerSize(),
"Attribute 'must_preserve_cheri_tags' cannot be set on copies "
"of less than capability size",
Call);
} else {
Assert(shouldPreserveTags(MI) != PreserveCheriTags::Required,
"Attribute 'must_preserve_cheri_tags' cannot be used with memset",
Call);
Assert(shouldPreserveTags(MI) != PreserveCheriTags::Unnecessary,
"Attribute 'no_preserve_cheri_tags' cannot be used with memset",
Call);
}

break;
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75 changes: 0 additions & 75 deletions llvm/test/CodeGen/Mips/memcpy-nobuiltin.ll
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39 changes: 39 additions & 0 deletions llvm/test/Verifier/cheri-preserve-tags.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,39 @@
; RUN: not opt -S %s -verify 2>&1 | FileCheck %s --check-prefixes=CHECK,PURECAP
; RUN: not opt -data-layout="p0:64:64:64" -S %s -verify 2>&1 | FileCheck %s --check-prefixes=CHECK,NON-CHERI

target datalayout = "pf200:128:128:128:64"

declare void @llvm.memcpy.p200i8.p200i8.i64(i8 addrspace(200)* nocapture writeonly, i8 addrspace(200)* nocapture readonly, i64, i1)
declare void @llvm.memmove.p200i8.p200i8.i64(i8 addrspace(200)* nocapture writeonly, i8 addrspace(200)* nocapture readonly, i64, i1)
declare void @llvm.memset.p200i8.i64(i8 addrspace(200)* nocapture, i8, i64, i1) nounwind

define void @too_small(i8 addrspace(200)* %dst, i8 addrspace(200)* %src) #0 {
entry:

call void @llvm.memcpy.p200i8.p200i8.i64(i8 addrspace(200)* align 1 %dst, i8 addrspace(200)* align 16 %src, i64 15, i1 false) must_preserve_cheri_tags
; PURECAP: Attribute 'must_preserve_cheri_tags' cannot be set on copies of less than capability size
; NON-CHERI: Attribute 'must_preserve_cheri_tags' requires a CHERI target
; CHECK-NEXT: call void @llvm.memcpy.p200i8.p200i8.i64(i8 addrspace(200)* align 1 %dst, i8 addrspace(200)* align 16 %src, i64 15, i1 false)
call void @llvm.memmove.p200i8.p200i8.i64(i8 addrspace(200)* align 1 %dst, i8 addrspace(200)* align 16 %src, i64 15, i1 false) must_preserve_cheri_tags
; PURECAP-NEXT: Attribute 'must_preserve_cheri_tags' cannot be set on copies of less than capability size
; NON-CHERI-NEXT: Attribute 'must_preserve_cheri_tags' requires a CHERI target
; CHECK-NEXT: call void @llvm.memmove.p200i8.p200i8.i64(i8 addrspace(200)* align 1 %dst, i8 addrspace(200)* align 16 %src, i64 15, i1 false)
ret void
}

define void @memset_invalid(i8 addrspace(200)* %dst, i8 addrspace(200)* %src) #0 {
entry:
call void @llvm.memset.p200i8.i64(i8 addrspace(200)* align 16 %dst, i8 0, i64 16, i1 false) must_preserve_cheri_tags
; NON-CHERI-NEXT: Attribute 'must_preserve_cheri_tags' requires a CHERI target
; NON-CHERI-NEXT: call void @llvm.memset.p200i8.i64(i8 addrspace(200)* align 16 %dst, i8 0, i64 16, i1 false)
; CHECK-NEXT: Attribute 'must_preserve_cheri_tags' cannot be used with memset
; CHECK-NEXT: call void @llvm.memset.p200i8.i64(i8 addrspace(200)* align 16 %dst, i8 0, i64 16, i1 false)
call void @llvm.memset.p200i8.i64(i8 addrspace(200)* align 16 %dst, i8 0, i64 16, i1 false) no_preserve_cheri_tags
; NON-CHERI-NEXT: Attribute 'no_preserve_cheri_tags' requires a CHERI target
; NON-CHERI-NEXT: call void @llvm.memset.p200i8.i64(i8 addrspace(200)* align 16 %dst, i8 0, i64 16, i1 false)
; CHECK-NEXT: Attribute 'no_preserve_cheri_tags' cannot be used with memset
; CHECK-NEXT: call void @llvm.memset.p200i8.i64(i8 addrspace(200)* align 16 %dst, i8 0, i64 16, i1 false)
ret void
}

; CHECK-NEXT: error: input module is broken!