Skip to content

Commit

Permalink
[ELF] Pass Ctx & to Relocations
Browse files Browse the repository at this point in the history
  • Loading branch information
@MaskRay
MaskRay committed Sep 29, 2024
1 parent d30d251 commit 29783f7
Show file tree
Hide file tree
Showing 7 changed files with 50 additions and 48 deletions.
2 changes: 1 addition & 1 deletion lld/ELF/Arch/SystemZ.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -453,7 +453,7 @@ bool SystemZ::relaxOnce(int pass) const {
continue;
if (rel.sym->auxIdx == 0) {
rel.sym->allocateAux();
addGotEntry(*rel.sym);
addGotEntry(ctx, *rel.sym);
changed = true;
}
rel.expr = R_GOT_PC;
Expand Down
2 changes: 1 addition & 1 deletion lld/ELF/Arch/X86_64.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -339,7 +339,7 @@ bool X86_64::relaxOnce(int pass) const {
continue;
if (rel.sym->auxIdx == 0) {
rel.sym->allocateAux();
addGotEntry(*rel.sym);
addGotEntry(ctx, *rel.sym);
changed = true;
}
rel.expr = R_GOT_PC;
Expand Down
77 changes: 39 additions & 38 deletions lld/ELF/Relocations.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,19 +65,20 @@ using namespace llvm::support::endian;
using namespace lld;
using namespace lld::elf;

static std::optional<std::string> getLinkerScriptLocation(const Symbol &sym) {
static std::optional<std::string> getLinkerScriptLocation(Ctx &ctx,
const Symbol &sym) {
for (SectionCommand *cmd : ctx.script->sectionCommands)
if (auto *assign = dyn_cast<SymbolAssignment>(cmd))
if (assign->sym == &sym)
return assign->location;
return std::nullopt;
}

static std::string getDefinedLocation(const Symbol &sym) {
static std::string getDefinedLocation(Ctx &ctx, const Symbol &sym) {
const char msg[] = "\n>>> defined in ";
if (sym.file)
return msg + toString(sym.file);
if (std::optional<std::string> loc = getLinkerScriptLocation(sym))
if (std::optional<std::string> loc = getLinkerScriptLocation(ctx, sym))
return msg + *loc;
return "";
}
Expand All @@ -87,9 +88,9 @@ static std::string getDefinedLocation(const Symbol &sym) {
// >>> defined in /home/alice/src/foo.o
// >>> referenced by bar.c:12 (/home/alice/src/bar.c:12)
// >>> /home/alice/src/bar.o:(.text+0x1)
static std::string getLocation(InputSectionBase &s, const Symbol &sym,
static std::string getLocation(Ctx &ctx, InputSectionBase &s, const Symbol &sym,
uint64_t off) {
std::string msg = getDefinedLocation(sym) + "\n>>> referenced by ";
std::string msg = getDefinedLocation(ctx, sym) + "\n>>> referenced by ";
std::string src = s.getSrcMsg(sym, off);
if (!src.empty())
msg += src + "\n>>> ";
Expand All @@ -116,7 +117,7 @@ void elf::reportRangeError(uint8_t *loc, const Relocation &rel, const Twine &v,
if (!errPlace.srcLoc.empty())
hint += "\n>>> referenced by " + errPlace.srcLoc;
if (rel.sym && !rel.sym->isSection())
hint += getDefinedLocation(*rel.sym);
hint += getDefinedLocation(ctx, *rel.sym);

if (errPlace.isec && errPlace.isec->name.starts_with(".debug"))
hint += "; consider recompiling with -fdebug-types-section to reduce size "
Expand All @@ -127,13 +128,13 @@ void elf::reportRangeError(uint8_t *loc, const Relocation &rel, const Twine &v,
", " + Twine(max).str() + "]" + hint);
}

void elf::reportRangeError(uint8_t *loc, int64_t v, int n, const Symbol &sym,
const Twine &msg) {
void elf::reportRangeError(Ctx &ctx, uint8_t *loc, int64_t v, int n,
const Symbol &sym, const Twine &msg) {
ErrorPlace errPlace = getErrorPlace(loc);
std::string hint;
if (!sym.getName().empty())
hint =
"; references '" + lld::toString(sym) + '\'' + getDefinedLocation(sym);
hint = "; references '" + lld::toString(sym) + '\'' +
getDefinedLocation(ctx, sym);
errorOrWarn(errPlace.loc + msg + " is out of range: " + Twine(v) +
" is not in [" + Twine(llvm::minIntN(n)) + ", " +
Twine(llvm::maxIntN(n)) + "]" + hint);
Expand Down Expand Up @@ -926,7 +927,7 @@ static void addPltEntry(PltSection &plt, GotPltSection &gotPlt,
sym, 0, R_ABS});
}

void elf::addGotEntry(Symbol &sym) {
void elf::addGotEntry(Ctx &ctx, Symbol &sym) {
ctx.in.got->addEntry(sym);
uint64_t off = sym.getGotOffset();

Expand Down Expand Up @@ -960,7 +961,7 @@ static void addTpOffsetGotEntry(Symbol &sym) {
// Return true if we can define a symbol in the executable that
// contains the value/function of a symbol defined in a shared
// library.
static bool canDefineSymbolInExecutable(Symbol &sym) {
static bool canDefineSymbolInExecutable(Ctx &ctx, Symbol &sym) {
// If the symbol has default visibility the symbol defined in the
// executable will preempt it.
// Note that we want the visibility of the shared symbol itself, not
Expand Down Expand Up @@ -1041,7 +1042,7 @@ bool RelocationScanner::isStaticLinkTimeConstant(RelExpr e, RelType type,
return true;

error("relocation " + toString(type) + " cannot refer to absolute symbol: " +
toString(sym) + getLocation(*sec, sym, relOff));
toString(sym) + getLocation(ctx, *sec, sym, relOff));
return true;
}

Expand Down Expand Up @@ -1206,9 +1207,9 @@ void RelocationScanner::processAux(RelExpr expr, RelType type, uint64_t offset,
// R_AARCH64_AUTH_ABS64.
if (!ctx.arg.shared && sym.isShared() &&
!(ctx.arg.emachine == EM_AARCH64 && type == R_AARCH64_AUTH_ABS64)) {
if (!canDefineSymbolInExecutable(sym)) {
if (!canDefineSymbolInExecutable(ctx, sym)) {
errorOrWarn("cannot preempt symbol: " + toString(sym) +
getLocation(*sec, sym, offset));
getLocation(ctx, *sec, sym, offset));
return;
}

Expand All @@ -1219,7 +1220,7 @@ void RelocationScanner::processAux(RelExpr expr, RelType type, uint64_t offset,
error("unresolvable relocation " + toString(type) +
" against symbol '" + toString(*ss) +
"'; recompile with -fPIC or remove '-z nocopyreloc'" +
getLocation(*sec, sym, offset));
getLocation(ctx, *sec, sym, offset));
sym.setFlags(NEEDS_COPY);
}
sec->addReloc({expr, type, offset, addend, &sym});
Expand Down Expand Up @@ -1257,7 +1258,7 @@ void RelocationScanner::processAux(RelExpr expr, RelType type, uint64_t offset,
if (ctx.arg.pie && ctx.arg.emachine == EM_386)
errorOrWarn("symbol '" + toString(sym) +
"' cannot be preempted; recompile with -fPIE" +
getLocation(*sec, sym, offset));
getLocation(ctx, *sec, sym, offset));
sym.setFlags(NEEDS_COPY | NEEDS_PLT);
sec->addReloc({expr, type, offset, addend, &sym});
return;
Expand All @@ -1267,7 +1268,7 @@ void RelocationScanner::processAux(RelExpr expr, RelType type, uint64_t offset,
errorOrWarn("relocation " + toString(type) + " cannot be used against " +
(sym.getName().empty() ? "local symbol"
: "symbol '" + toString(sym) + "'") +
"; recompile with -fPIC" + getLocation(*sec, sym, offset));
"; recompile with -fPIC" + getLocation(ctx, *sec, sym, offset));
}

// This function is similar to the `handleTlsRelocation`. MIPS does not
Expand Down Expand Up @@ -1306,7 +1307,7 @@ unsigned RelocationScanner::handleTlsRelocation(RelExpr expr, RelType type,
if (ctx.arg.shared) {
errorOrWarn("relocation " + toString(type) + " against " + toString(sym) +
" cannot be used with -shared" +
getLocation(*sec, sym, offset));
getLocation(ctx, *sec, sym, offset));
return 1;
}
return 0;
Expand Down Expand Up @@ -1515,7 +1516,7 @@ void RelocationScanner::scanOne(typename Relocs<RelTy>::const_iterator &i) {
if (i == end) {
errorOrWarn("R_PPC64_TLSGD/R_PPC64_TLSLD may not be the last "
"relocation" +
getLocation(*sec, sym, offset));
getLocation(ctx, *sec, sym, offset));
return;
}
}
Expand Down Expand Up @@ -1694,7 +1695,7 @@ template <class ELFT> void elf::scanRelocations(Ctx &ctx) {
outerFn();
}

static bool handleNonPreemptibleIfunc(Symbol &sym, uint16_t flags) {
static bool handleNonPreemptibleIfunc(Ctx &ctx, Symbol &sym, uint16_t flags) {
// Handle a reference to a non-preemptible ifunc. These are special in a
// few ways:
//
Expand Down Expand Up @@ -1770,7 +1771,7 @@ static bool handleNonPreemptibleIfunc(Symbol &sym, uint16_t flags) {
d.type = STT_FUNC;

if (flags & NEEDS_GOT)
addGotEntry(sym);
addGotEntry(ctx, sym);
} else if (flags & NEEDS_GOT) {
// Redirect GOT accesses to point to the Igot.
sym.gotInIgot = true;
Expand All @@ -1781,7 +1782,7 @@ static bool handleNonPreemptibleIfunc(Symbol &sym, uint16_t flags) {
void elf::postScanRelocations(Ctx &ctx) {
auto fn = [&](Symbol &sym) {
auto flags = sym.flags.load(std::memory_order_relaxed);
if (handleNonPreemptibleIfunc(sym, flags))
if (handleNonPreemptibleIfunc(ctx, sym, flags))
return;

if (sym.isTagged() && sym.isDefined())
Expand All @@ -1792,7 +1793,7 @@ void elf::postScanRelocations(Ctx &ctx) {
sym.allocateAux();

if (flags & NEEDS_GOT)
addGotEntry(sym);
addGotEntry(ctx, sym);
if (flags & NEEDS_PLT)
addPltEntry(*ctx.in.plt, *ctx.in.gotPlt, *ctx.in.relaPlt,
ctx.target->pltRel, sym);
Expand Down Expand Up @@ -2052,7 +2053,7 @@ void ThunkCreator::mergeThunks(ArrayRef<OutputSection *> outputSections) {
});
}

static int64_t getPCBias(RelType type) {
static int64_t getPCBias(Ctx &ctx, RelType type) {
if (ctx.arg.emachine != EM_ARM)
return 0;
switch (type) {
Expand All @@ -2074,7 +2075,7 @@ ThunkSection *ThunkCreator::getISDThunkSec(OutputSection *os,
const Relocation &rel,
uint64_t src) {
// See the comment in getThunk for -pcBias below.
const int64_t pcBias = getPCBias(rel.type);
const int64_t pcBias = getPCBias(ctx, rel.type);
for (std::pair<ThunkSection *, uint32_t> tp : isd->thunkSections) {
ThunkSection *ts = tp.first;
uint64_t tsBase = os->addr + ts->outSecOff - pcBias;
Expand Down Expand Up @@ -2235,7 +2236,7 @@ std::pair<Thunk *, bool> ThunkCreator::getThunk(InputSection *isec,
// out in the relocation addend. We compensate for the PC bias so that
// an Arm and Thumb relocation to the same destination get the same keyAddend,
// which is usually 0.
const int64_t pcBias = getPCBias(rel.type);
const int64_t pcBias = getPCBias(ctx, rel.type);
const int64_t keyAddend = rel.addend + pcBias;

// We use a ((section, offset), addend) pair to find the thunk position if
Expand Down Expand Up @@ -2357,7 +2358,7 @@ bool ThunkCreator::createThunks(uint32_t pass,
// STT_SECTION + non-zero addend, clear the addend after
// redirection.
if (ctx.arg.emachine != EM_MIPS)
rel.addend = -getPCBias(rel.type);
rel.addend = -getPCBias(ctx, rel.type);
}

for (auto &p : isd->thunkSections)
Expand Down Expand Up @@ -2390,13 +2391,13 @@ bool elf::hexagonNeedsTLSSymbol(ArrayRef<OutputSection *> outputSections) {
return needTlsSymbol;
}

void elf::hexagonTLSSymbolUpdate(ArrayRef<OutputSection *> outputSections) {
void elf::hexagonTLSSymbolUpdate(Ctx &ctx) {
Symbol *sym = ctx.symtab->find("__tls_get_addr");
if (!sym)
return;
bool needEntry = true;
forEachInputSectionDescription(
outputSections, [&](OutputSection *os, InputSectionDescription *isd) {
ctx.outputSections, [&](OutputSection *os, InputSectionDescription *isd) {
for (InputSection *isec : isd->sections)
for (Relocation &rel : isec->relocs())
if (rel.sym->type == llvm::ELF::STT_TLS && rel.expr == R_PLT_PC) {
Expand All @@ -2418,8 +2419,8 @@ static bool matchesRefTo(const NoCrossRefCommand &cmd, StringRef osec) {
}

template <class ELFT, class Rels>
static void scanCrossRefs(const NoCrossRefCommand &cmd, OutputSection *osec,
InputSection *sec, Rels rels) {
static void scanCrossRefs(Ctx &ctx, const NoCrossRefCommand &cmd,
OutputSection *osec, InputSection *sec, Rels rels) {
for (const auto &r : rels) {
Symbol &sym = sec->file->getSymbol(r.getSymbol(ctx.arg.isMips64EL));
// A legal cross-reference is when the destination output section is
Expand All @@ -2442,7 +2443,7 @@ static void scanCrossRefs(const NoCrossRefCommand &cmd, OutputSection *osec,

// For each output section described by at least one NOCROSSREFS(_TO) command,
// scan relocations from its input sections for prohibited cross references.
template <class ELFT> void elf::checkNoCrossRefs() {
template <class ELFT> void elf::checkNoCrossRefs(Ctx &ctx) {
for (OutputSection *osec : ctx.outputSections) {
for (const NoCrossRefCommand &noxref : ctx.script->noCrossRefs) {
if (!llvm::is_contained(noxref.outputSections, osec->name) ||
Expand All @@ -2453,7 +2454,7 @@ template <class ELFT> void elf::checkNoCrossRefs() {
if (!isd)
continue;
parallelForEach(isd->sections, [&](InputSection *sec) {
invokeOnRelocs(*sec, scanCrossRefs<ELFT>, noxref, osec, sec);
invokeOnRelocs(*sec, scanCrossRefs<ELFT>, ctx, noxref, osec, sec);
});
}
}
Expand All @@ -2465,7 +2466,7 @@ template void elf::scanRelocations<ELF32BE>(Ctx &);
template void elf::scanRelocations<ELF64LE>(Ctx &);
template void elf::scanRelocations<ELF64BE>(Ctx &);

template void elf::checkNoCrossRefs<ELF32LE>();
template void elf::checkNoCrossRefs<ELF32BE>();
template void elf::checkNoCrossRefs<ELF64LE>();
template void elf::checkNoCrossRefs<ELF64BE>();
template void elf::checkNoCrossRefs<ELF32LE>(Ctx &);
template void elf::checkNoCrossRefs<ELF32BE>(Ctx &);
template void elf::checkNoCrossRefs<ELF64LE>(Ctx &);
template void elf::checkNoCrossRefs<ELF64BE>(Ctx &);
6 changes: 3 additions & 3 deletions lld/ELF/Relocations.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -143,12 +143,12 @@ struct JumpInstrMod {
// Call reportUndefinedSymbols() after calling scanRelocations() to emit
// the diagnostics.
template <class ELFT> void scanRelocations(Ctx &ctx);
template <class ELFT> void checkNoCrossRefs();
template <class ELFT> void checkNoCrossRefs(Ctx &ctx);
void reportUndefinedSymbols();
void postScanRelocations(Ctx &ctx);
void addGotEntry(Symbol &sym);
void addGotEntry(Ctx &ctx, Symbol &sym);

void hexagonTLSSymbolUpdate(ArrayRef<OutputSection *> outputSections);
void hexagonTLSSymbolUpdate(Ctx &ctx);
bool hexagonNeedsTLSSymbol(ArrayRef<OutputSection *> outputSections);

class ThunkSection;
Expand Down
4 changes: 2 additions & 2 deletions lld/ELF/Target.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -247,8 +247,8 @@ template <class ELFT> bool isMipsPIC(const Defined *sym);

void reportRangeError(uint8_t *loc, const Relocation &rel, const Twine &v,
int64_t min, uint64_t max);
void reportRangeError(uint8_t *loc, int64_t v, int n, const Symbol &sym,
const Twine &msg);
void reportRangeError(Ctx &ctx, uint8_t *loc, int64_t v, int n,
const Symbol &sym, const Twine &msg);

// Make sure that V can be represented as an N bit signed integer.
inline void checkInt(uint8_t *loc, int64_t v, int n, const Relocation &rel) {
Expand Down
3 changes: 2 additions & 1 deletion lld/ELF/Thunks.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1199,7 +1199,8 @@ void PPC64R12SetupStub::writeTo(uint8_t *buf) {
int64_t offset = (gotPlt ? destination.getGotPltVA() : destination.getVA()) -
getThunkTargetSym()->getVA();
if (!isInt<34>(offset))
reportRangeError(buf, offset, 34, destination, "R12 setup stub offset");
reportRangeError(ctx, buf, offset, 34, destination,
"R12 setup stub offset");

int nextInstOffset;
if (ctx.arg.power10Stubs) {
Expand Down
4 changes: 2 additions & 2 deletions lld/ELF/Writer.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1454,7 +1454,7 @@ template <class ELFT> void Writer<ELFT>::finalizeAddressDependentContent() {

// Converts call x@GDPLT to call __tls_get_addr
if (ctx.arg.emachine == EM_HEXAGON)
hexagonTLSSymbolUpdate(ctx.outputSections);
hexagonTLSSymbolUpdate(ctx);

uint32_t pass = 0, assignPasses = 0;
for (;;) {
Expand Down Expand Up @@ -1975,7 +1975,7 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {

if (ctx.script->noCrossRefs.size()) {
llvm::TimeTraceScope timeScope("Check NOCROSSREFS");
checkNoCrossRefs<ELFT>();
checkNoCrossRefs<ELFT>(ctx);
}

{
Expand Down

0 comments on commit 29783f7

Please sign in to comment.