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Merged
merged 12 commits into from
Oct 31, 2025
Merged

Merge another batch of CHERI changes from CTSRD #262

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17787b3
[RISCV][MC] Keep .Lpcrel_hi symbols for CHERI AUIPCC pseudos in assembly
jrtc27 May 22, 2025
a80d663
[ELF][NFC] Fix mismerge in CheriCapTableSection
jrtc27 May 23, 2025
7064460
[ELF][NFC] Add name constructor argument for CheriCapRelocsSection
jrtc27 May 23, 2025
b6463e9
[ELF] Calculate config->isCheriAbi prior to constructing TargetInfo
jrtc27 May 23, 2025
7960146
[ELF][RISCV] Set correct gotEntrySize for purecap objects
jrtc27 May 23, 2025
1f70b58
[InstSimplify] Add a test for current get/set intrinsic folding
arichardson Apr 17, 2023
9982278
[InstSimplify] Simplify getoffset/getaddr folding. NFC
arichardson May 12, 2023
a1583d6
[InstSimplify] Simplify @llvm.cheri.cap.high.get
arichardson May 28, 2025
2c29259
[RISCV] Enable a test that works these days
jrtc27 May 30, 2025
2494751
[RISCV] Fix a RUN line causing the test not to be run
jrtc27 May 30, 2025
30a07f1
[ELF][RISCV] Use .got rather than .captable for CHERI-RISC-V
jrtc27 May 30, 2025
f9ec9dc
[ELF][NFC] Drop unwarranted XXX comments
jrtc27 May 30, 2025
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12 changes: 9 additions & 3 deletions clang/test/CodeGen/cheri/vaddr-mode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,9 @@ long write_uintcap(__uintcap_t *cap) {
// OFFSET-NEXT: entry:
// OFFSET-NEXT: [[TMP0:%.*]] = tail call i64 @llvm.cheri.cap.offset.get.i64(ptr addrspace(200) [[CAP:%.*]])
// OFFSET-NEXT: [[AND:%.*]] = and i64 [[TMP0]], 3
// OFFSET-NEXT: ret i64 [[AND]]
// OFFSET-NEXT: [[TMP1:%.*]] = tail call ptr addrspace(200) @llvm.cheri.cap.offset.set.i64(ptr addrspace(200) [[CAP]], i64 [[AND]])
// OFFSET-NEXT: [[TMP2:%.*]] = tail call i64 @llvm.cheri.cap.offset.get.i64(ptr addrspace(200) [[TMP1]])
// OFFSET-NEXT: ret i64 [[TMP2]]
//
long get_low_bits(__uintcap_t cap) {
return cap & 3;
Expand Down Expand Up @@ -126,7 +128,9 @@ __uintcap_t xor_uintcap(__uintcap_t cap, __uintcap_t cap2) {
// OFFSET-NEXT: [[TMP0:%.*]] = tail call i64 @llvm.cheri.cap.offset.get.i64(ptr addrspace(200) [[CAP:%.*]])
// OFFSET-NEXT: [[TMP1:%.*]] = tail call i64 @llvm.cheri.cap.offset.get.i64(ptr addrspace(200) [[CAP2:%.*]])
// OFFSET-NEXT: [[XOR:%.*]] = xor i64 [[TMP1]], [[TMP0]]
// OFFSET-NEXT: ret i64 [[XOR]]
// OFFSET-NEXT: [[TMP2:%.*]] = tail call ptr addrspace(200) @llvm.cheri.cap.offset.set.i64(ptr addrspace(200) [[CAP]], i64 [[XOR]])
// OFFSET-NEXT: [[TMP3:%.*]] = tail call i64 @llvm.cheri.cap.offset.get.i64(ptr addrspace(200) [[TMP2]])
// OFFSET-NEXT: ret i64 [[TMP3]]
//
long xor_uintcap_return_long(__uintcap_t cap, __uintcap_t cap2) {
return cap ^ cap2;
Expand Down Expand Up @@ -160,7 +164,9 @@ __uintcap_t modulo_return_uintcap(__uintcap_t cap) {
// OFFSET-NEXT: entry:
// OFFSET-NEXT: [[TMP0:%.*]] = tail call i64 @llvm.cheri.cap.offset.get.i64(ptr addrspace(200) [[CAP:%.*]])
// OFFSET-NEXT: [[REM:%.*]] = and i64 [[TMP0]], 31
// OFFSET-NEXT: ret i64 [[REM]]
// OFFSET-NEXT: [[TMP1:%.*]] = tail call ptr addrspace(200) @llvm.cheri.cap.offset.set.i64(ptr addrspace(200) [[CAP]], i64 [[REM]])
// OFFSET-NEXT: [[TMP2:%.*]] = tail call i64 @llvm.cheri.cap.offset.get.i64(ptr addrspace(200) [[TMP1]])
// OFFSET-NEXT: ret i64 [[TMP2]]
//
long modulo_return_long(__uintcap_t cap) {
return cap % 32;
Expand Down
144 changes: 77 additions & 67 deletions lld/ELF/Arch/Cheri.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,17 @@ using namespace llvm::ELF;
namespace lld {
namespace elf {

bool isCheriAbi(const InputFile *f) {
switch (f->emachine) {
case EM_MIPS:
return (f->eflags & EF_MIPS_ABI) == EF_MIPS_ABI_CHERIABI;
case EM_RISCV:
return f->eflags & EF_RISCV_CHERIABI;
default:
return false;
}
}

bool hasDynamicLinker(Ctx &ctx) {
return ctx.arg.shared || ctx.arg.pie || !ctx.sharedFiles.empty();
}
Expand All @@ -43,10 +54,10 @@ struct InMemoryCapRelocEntry {
CapRelocUint permissions;
};

CheriCapRelocsSection::CheriCapRelocsSection(Ctx &ctx)
: SyntheticSection(ctx, "__cap_relocs", SHT_PROGBITS,
CheriCapRelocsSection::CheriCapRelocsSection(Ctx &ctx, StringRef name)
: SyntheticSection(ctx, name, SHT_PROGBITS,
(ctx.arg.isPic && !ctx.arg.relativeCapRelocsOnly)
? SHF_ALLOC | SHF_WRITE /* XXX: actually RELRO */
? SHF_ALLOC | SHF_WRITE
: SHF_ALLOC,
ctx.arg.wordsize) {
this->entsize = ctx.arg.wordsize * 5;
Expand Down Expand Up @@ -592,16 +603,14 @@ void CheriCapRelocsSection::writeTo(uint8_t *buf) {
invokeELFT(writeToImpl, buf);
}

CheriCapTableSection::CheriCapTableSection(Ctx &ctx)
: SyntheticSection(
ctx, ".captable", SHT_PROGBITS,
SHF_ALLOC | SHF_WRITE, /* XXX: actually RELRO for BIND_NOW*/
ctx.arg.capabilitySize) {
MipsCheriCapTableSection::MipsCheriCapTableSection(Ctx &ctx)
: SyntheticSection(ctx, ".captable", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE,
ctx.arg.capabilitySize) {
assert(ctx.arg.capabilitySize > 0);
this->entsize = ctx.arg.capabilitySize;
}

void CheriCapTableSection::writeTo(uint8_t *buf) {
void MipsCheriCapTableSection::writeTo(uint8_t *buf) {
// Capability part should be filled with all zeros and crt_init_globals fills
// it in. For the TLS part, assignValuesAndAddCapTableSymbols adds any static
// relocations needed, and should be procesed by relocateAlloc.
Expand All @@ -614,8 +623,8 @@ static Defined *findMatchingFunction(const InputSectionBase *isec,
return isec->getEnclosingFunction(symOffset);
}

CheriCapTableSection::CaptableMap &
CheriCapTableSection::getCaptableMapForFileAndOffset(
MipsCheriCapTableSection::CaptableMap &
MipsCheriCapTableSection::getCaptableMapForFileAndOffset(
const InputSectionBase *isec, uint64_t offset) {
if (LLVM_LIKELY(ctx.arg.capTableScope == CapTableScopePolicy::All))
return globalEntries;
Expand All @@ -637,47 +646,48 @@ CheriCapTableSection::getCaptableMapForFileAndOffset(
return globalEntries;
}

void CheriCapTableSection::addEntry(Symbol &sym, RelExpr expr,
InputSectionBase *isec, uint64_t offset) {
void MipsCheriCapTableSection::addEntry(Symbol &sym, RelExpr expr,
InputSectionBase *isec,
uint64_t offset) {
// FIXME: can this be called from multiple threads?
CapTableIndex idx;
idx.needsSmallImm = false;
idx.usedInCallExpr = false;
idx.firstUse = SymbolAndOffset(isec, offset);
assert(!idx.firstUse->symOrSec.isNull());
switch (expr) {
case R_CHERI_CAPABILITY_TABLE_INDEX_SMALL_IMMEDIATE:
case R_CHERI_CAPABILITY_TABLE_INDEX_CALL_SMALL_IMMEDIATE:
idx.needsSmallImm = true;
break;
default:
break;
case R_MIPS_CHERI_CAPTAB_INDEX_SMALL_IMMEDIATE:
case R_MIPS_CHERI_CAPTAB_INDEX_CALL_SMALL_IMMEDIATE:
idx.needsSmallImm = true;
break;
default:
break;
}
// If the symbol is only ever referenced by the captable call relocations we
// can emit a capability call relocation instead of a normal capability
// relocation. This indicates to the runtime linker that the capability is
// not used as a function pointer and therefore does not need a unique
// address (plt stub) across all DSOs.
switch (expr) {
case R_CHERI_CAPABILITY_TABLE_INDEX_CALL:
case R_CHERI_CAPABILITY_TABLE_INDEX_CALL_SMALL_IMMEDIATE:
if (!sym.isFunc() && !sym.isUndefWeak()) {
CheriCapRelocLocation loc{isec, offset};
std::string msg = "call relocation against non-function symbol " +
verboseToString(ctx, &sym, 0) + "\n>>> referenced by " +
loc.toString(ctx);
if (sym.isUndefined() &&
ctx.arg.unresolvedSymbolsInShlib == UnresolvedPolicy::Ignore) {
// Don't fail the build for shared libraries unless
nonFatalWarning(msg);
} else {
warn(msg);
}
case R_MIPS_CHERI_CAPTAB_INDEX_CALL:
case R_MIPS_CHERI_CAPTAB_INDEX_CALL_SMALL_IMMEDIATE:
if (!sym.isFunc() && !sym.isUndefWeak()) {
CheriCapRelocLocation loc{isec, offset};
std::string msg = "call relocation against non-function symbol " +
verboseToString(ctx, &sym, 0) + "\n>>> referenced by " +
loc.toString(ctx);
if (sym.isUndefined() &&
ctx.arg.unresolvedSymbolsInShlib == UnresolvedPolicy::Ignore) {
// Don't fail the build for shared libraries unless
nonFatalWarning(msg);
} else {
warn(msg);
}
idx.usedInCallExpr = true;
break;
default:
break;
}
idx.usedInCallExpr = true;
break;
default:
break;
}
CaptableMap &entries = getCaptableMapForFileAndOffset(isec, offset);
if (ctx.arg.zCapTableDebug) {
Expand All @@ -700,25 +710,25 @@ void CheriCapTableSection::addEntry(Symbol &sym, RelExpr expr,
}
}

void CheriCapTableSection::addDynTlsEntry(Symbol &sym) {
void MipsCheriCapTableSection::addDynTlsEntry(Symbol &sym) {
dynTlsEntries.map.insert(std::make_pair(&sym, CapTableIndex()));
}

void CheriCapTableSection::addTlsIndex() {
void MipsCheriCapTableSection::addTlsIndex() {
dynTlsEntries.map.insert(std::make_pair(nullptr, CapTableIndex()));
}

void CheriCapTableSection::addTlsEntry(Symbol &sym) {
void MipsCheriCapTableSection::addTlsEntry(Symbol &sym) {
tlsEntries.map.insert(std::make_pair(&sym, CapTableIndex()));
}

uint32_t CheriCapTableSection::getIndex(const Symbol &sym,
const InputSectionBase *isec,
uint64_t offset) const {
uint32_t MipsCheriCapTableSection::getIndex(const Symbol &sym,
const InputSectionBase *isec,
uint64_t offset) const {
assert(valuesAssigned && "getIndex called before index assignment");
const CaptableMap &entries =
const_cast<CheriCapTableSection *>(this)->getCaptableMapForFileAndOffset(
isec, offset);
const_cast<MipsCheriCapTableSection *>(this)
->getCaptableMapForFileAndOffset(isec, offset);
auto it = entries.map.find(const_cast<Symbol *>(&sym));
assert(entries.firstIndex != std::numeric_limits<uint64_t>::max() &&
"First index not set yet?");
Expand All @@ -730,31 +740,31 @@ uint32_t CheriCapTableSection::getIndex(const Symbol &sym,
return *it->second.index - entries.firstIndex;
}

uint32_t CheriCapTableSection::getDynTlsOffset(const Symbol &sym) const {
uint32_t MipsCheriCapTableSection::getDynTlsOffset(const Symbol &sym) const {
assert(valuesAssigned && "getDynTlsOffset called before index assignment");
auto it = dynTlsEntries.map.find(const_cast<Symbol *>(&sym));
assert(it != dynTlsEntries.map.end());
return *it->second.index * ctx.arg.wordsize;
}

uint32_t CheriCapTableSection::getTlsIndexOffset() const {
uint32_t MipsCheriCapTableSection::getTlsIndexOffset() const {
assert(valuesAssigned && "getTlsIndexOffset called before index assignment");
auto it = dynTlsEntries.map.find(nullptr);
assert(it != dynTlsEntries.map.end());
return *it->second.index * ctx.arg.wordsize;
}

uint32_t CheriCapTableSection::getTlsOffset(const Symbol &sym) const {
uint32_t MipsCheriCapTableSection::getTlsOffset(const Symbol &sym) const {
assert(valuesAssigned && "getTlsOffset called before index assignment");
auto it = tlsEntries.map.find(const_cast<Symbol *>(&sym));
assert(it != tlsEntries.map.end());
return *it->second.index * ctx.arg.wordsize;
}

template <class ELFT>
uint64_t CheriCapTableSection::assignIndices(uint64_t startIndex,
CaptableMap &entries,
const Twine &symContext) {
uint64_t MipsCheriCapTableSection::assignIndices(uint64_t startIndex,
CaptableMap &entries,
const Twine &symContext) {
// Usually StartIndex will be zero (one global captable) but if we are
// compiling with per-file/per-function
uint64_t smallEntryCount = 0;
Expand Down Expand Up @@ -864,7 +874,7 @@ uint64_t CheriCapTableSection::assignIndices(uint64_t startIndex,
? ctx.in.relaPlt.get()
: ctx.mainPart->relaDyn.get();
addCapabilityRelocation<ELFT>(
ctx, targetSym, elfCapabilityReloc, ctx.in.cheriCapTable.get(), off,
ctx, targetSym, elfCapabilityReloc, ctx.in.mipsCheriCapTable.get(), off,
R_CHERI_CAPABILITY, 0, it.second.usedInCallExpr,
[&]() {
return ("\n>>> referenced by " + refName + "\n>>> first used in " +
Expand All @@ -878,7 +888,7 @@ uint64_t CheriCapTableSection::assignIndices(uint64_t startIndex,
}

template <class ELFT>
void CheriCapTableSection::assignValuesAndAddCapTableSymbols() {
void MipsCheriCapTableSection::assignValuesAndAddCapTableSymbols() {
// First assign the global indices (which will usually be the only ones)
uint64_t assignedEntries = assignIndices<ELFT>(0, globalEntries, "");
if (LLVM_UNLIKELY(ctx.arg.capTableScope != CapTableScopePolicy::All)) {
Expand Down Expand Up @@ -961,7 +971,6 @@ void CheriCapTableSection::assignValuesAndAddCapTableSymbols() {
this->relocations.push_back(
{R_TPREL, ctx.target->symbolicRel, offset, 0, s});
else
// FIXME: casting to GotSection here is a massive hack!!
ctx.mainPart->relaDyn->addAddendOnlyRelocIfNonPreemptible(
ctx.target->tlsGotRel, *this, offset, *s, ctx.target->symbolicRel);
}
Expand All @@ -970,22 +979,22 @@ void CheriCapTableSection::assignValuesAndAddCapTableSymbols() {
}

template void
CheriCapTableSection::assignValuesAndAddCapTableSymbols<ELF32LE>();
MipsCheriCapTableSection::assignValuesAndAddCapTableSymbols<ELF32LE>();
template void
CheriCapTableSection::assignValuesAndAddCapTableSymbols<ELF32BE>();
MipsCheriCapTableSection::assignValuesAndAddCapTableSymbols<ELF32BE>();
template void
CheriCapTableSection::assignValuesAndAddCapTableSymbols<ELF64LE>();
MipsCheriCapTableSection::assignValuesAndAddCapTableSymbols<ELF64LE>();
template void
CheriCapTableSection::assignValuesAndAddCapTableSymbols<ELF64BE>();
MipsCheriCapTableSection::assignValuesAndAddCapTableSymbols<ELF64BE>();

CheriCapTableMappingSection::CheriCapTableMappingSection(Ctx &ctx)
MipsCheriCapTableMappingSection::MipsCheriCapTableMappingSection(Ctx &ctx)
: SyntheticSection(ctx, ".captable_mapping", SHT_PROGBITS, SHF_ALLOC, 8) {
assert(ctx.arg.capabilitySize > 0);
this->entsize = sizeof(CaptableMappingEntry);
static_assert(sizeof(CaptableMappingEntry) == 24, "");
}

size_t CheriCapTableMappingSection::getSize() const {
size_t MipsCheriCapTableMappingSection::getSize() const {
assert(ctx.arg.capTableScope != CapTableScopePolicy::All);
if (!isNeeded()) return 0;
size_t count = 0;
Expand All @@ -1000,9 +1009,10 @@ size_t CheriCapTableMappingSection::getSize() const {
return count * sizeof(CaptableMappingEntry);
}

void CheriCapTableMappingSection::writeTo(uint8_t *buf) {
void MipsCheriCapTableMappingSection::writeTo(uint8_t *buf) {
assert(ctx.arg.capTableScope != CapTableScopePolicy::All);
if (!ctx.in.cheriCapTable) return;
if (!ctx.in.mipsCheriCapTable)
return;
if (!ctx.in.symTab) {
error("Cannot write " + this->name + " without .symtab section!");
return;
Expand All @@ -1015,14 +1025,14 @@ void CheriCapTableMappingSection::writeTo(uint8_t *buf) {
for (const SymbolTableEntry &ste : ctx.in.symTab->getSymbols()) {
Symbol *sym = ste.sym;
if (!sym->isDefined() || !sym->isFunc()) continue;
const CheriCapTableSection::CaptableMap *capTableMap = nullptr;
const MipsCheriCapTableSection::CaptableMap *capTableMap = nullptr;
if (ctx.arg.capTableScope == CapTableScopePolicy::Function) {
auto it = ctx.in.cheriCapTable->perFunctionEntries.find(sym);
if (it != ctx.in.cheriCapTable->perFunctionEntries.end())
auto it = ctx.in.mipsCheriCapTable->perFunctionEntries.find(sym);
if (it != ctx.in.mipsCheriCapTable->perFunctionEntries.end())
capTableMap = &it->second;
} else if (ctx.arg.capTableScope == CapTableScopePolicy::File) {
auto it = ctx.in.cheriCapTable->perFileEntries.find(sym->file);
if (it != ctx.in.cheriCapTable->perFileEntries.end())
auto it = ctx.in.mipsCheriCapTable->perFileEntries.find(sym->file);
if (it != ctx.in.mipsCheriCapTable->perFileEntries.end())
capTableMap = &it->second;
} else {
llvm_unreachable("Invalid mode!");
Expand Down
14 changes: 7 additions & 7 deletions lld/ELF/Arch/Cheri.h
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Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,7 @@ struct CheriCapReloc {
// FIXME: should de-template this class properly
class CheriCapRelocsSection : public SyntheticSection {
public:
CheriCapRelocsSection(Ctx &ctx);
CheriCapRelocsSection(Ctx &ctx, StringRef name);
// Add a __cap_relocs section from in input object file
template <class ELFT>
void addSection(InputSectionBase *s);
Expand Down Expand Up @@ -186,9 +186,9 @@ class CheriCapRelocsSection : public SyntheticSection {
// +---------------------------------------+
// TODO: TLS caps also need to be per file/function

class CheriCapTableSection : public SyntheticSection {
class MipsCheriCapTableSection : public SyntheticSection {
public:
CheriCapTableSection(Ctx &ctx);
MipsCheriCapTableSection(Ctx &ctx);
// InputFile and Offset is needed in order to implement per-file/per-function
// tables
void addEntry(Symbol &sym, RelExpr expr, InputSectionBase *isec,
Expand Down Expand Up @@ -266,7 +266,7 @@ class CheriCapTableSection : public SyntheticSection {
CaptableMap dynTlsEntries;
CaptableMap tlsEntries;
bool valuesAssigned = false;
friend class CheriCapTableMappingSection;
friend class MipsCheriCapTableMappingSection;
};

// TODO: could shrink these to reduce size overhead but this is experimental
Expand All @@ -280,13 +280,13 @@ struct CaptableMappingEntry {

// Map from symbol vaddr -> captable subset so that RTLD can setup the correct
// trampolines to initialize $cgp to the correct subset
class CheriCapTableMappingSection : public SyntheticSection {
class MipsCheriCapTableMappingSection : public SyntheticSection {
public:
CheriCapTableMappingSection(Ctx &ctx);
MipsCheriCapTableMappingSection(Ctx &ctx);
bool isNeeded() const override {
if (ctx.arg.capTableScope == CapTableScopePolicy::All)
return false;
return ctx.in.cheriCapTable && ctx.in.cheriCapTable->isNeeded();
return ctx.in.mipsCheriCapTable && ctx.in.mipsCheriCapTable->isNeeded();
}
void writeTo(uint8_t *buf) override;
size_t getSize() const override;
Expand Down
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