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[lld] More info for aarch64 ldr/str misaligning error #135004

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[lld] More info for aarch64 ldr/str misaligning error #135004

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More logging info for lld 
Co-authored-by: Kirill Andreev <hindmost.one@gmail.com>
Co-authored-by: Andrei Borzenkov <root@sandwitch.dev>
Co-authored-by: Dmitrii Egorov <egorov.d.i@icloud.com>
Co-authored-by: Danil Berestov <goosedb@yandex.ru>
Co-authored-by: Ilya Baryshnikov <zlonast3@gmail.com>
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@GulinSS @Heimdell
@s-and-witch @goosedb @zlonast
6 people committed Apr 9, 2025
commit a6b7acc3b8645209767c03ece233b8d0e8f2513e
43 changes: 31 additions & 12 deletions lld/COFF/Chunks.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -268,15 +268,17 @@ void applyArm64Imm(uint8_t *off, uint64_t imm, uint32_t rangeLimit) {
// Even if larger loads/stores have a larger range, limit the
// effective offset to 12 bit, since it is intended to be a
// page offset.
static void applyArm64Ldr(uint8_t *off, uint64_t imm) {
static void applyArm64Ldr(const Twine &msg_location, uint8_t *off, uint64_t imm) {
uint32_t orig = read32le(off);
uint32_t size = orig >> 30;
// 0x04000000 indicates SIMD/FP registers
// 0x00800000 indicates 128 bit
if ((orig & 0x4800000) == 0x4800000)
size += 4;
if ((imm & ((1 << size) - 1)) != 0)
error("misaligned ldr/str offset");
error(llvm::Twine {"misaligned ldr/str offset: 0x"} + llvm::Twine::utohexstr(imm)
+ "@" + llvm::Twine::utohexstr(static_cast<uint64_t>(orig))
+ " with align 2^" + llvm::Twine(size) + " from " + msg_location);
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I think it would be better to just display the alignment, ie. llvm::Twine(1 << size)

applyArm64Imm(off, imm >> size, size);
}

Expand All @@ -299,10 +301,10 @@ static void applySecRelHigh12A(const SectionChunk *sec, uint8_t *off,
applyArm64Imm(off, secRel & 0xfff, 0);
}

static void applySecRelLdr(const SectionChunk *sec, uint8_t *off,
static void applySecRelLdr(const SectionChunk *sec, const Twine &msg_location, uint8_t *off,
OutputSection *os, uint64_t s) {
if (checkSecRel(sec, os))
applyArm64Ldr(off, (s - os->getRVA()) & 0xfff);
applyArm64Ldr(msg_location, off, (s - os->getRVA()) & 0xfff);
}

void applyArm64Branch26(uint8_t *off, int64_t v) {
Expand All @@ -323,14 +325,23 @@ static void applyArm64Branch14(uint8_t *off, int64_t v) {
or32(off, (v & 0x0000FFFC) << 3);
}

void SectionChunk::applyRelARM64(uint8_t *off, uint16_t type, OutputSection *os,
void SectionChunk::applyRelARM64(uint8_t *off, const coff_relocation &rel, OutputSection *os,
uint64_t s, uint64_t p,
uint64_t imageBase) const {
switch (type) {
// COPY FROM: maybeReportRelocationToDiscarded
StringRef sym_name;
if (this->sym) {
sym_name = this->sym->getName();
} else {
COFFSymbolRef coffSym = check(this->file->getCOFFObj()->getSymbol(rel.SymbolTableIndex));
sym_name = check(this->file->getCOFFObj()->getSymbolName(coffSym));
}

switch (rel.Type) {
case IMAGE_REL_ARM64_PAGEBASE_REL21: applyArm64Addr(off, s, p, 12); break;
case IMAGE_REL_ARM64_REL21: applyArm64Addr(off, s, p, 0); break;
case IMAGE_REL_ARM64_PAGEOFFSET_12A: applyArm64Imm(off, s & 0xfff, 0); break;
case IMAGE_REL_ARM64_PAGEOFFSET_12L: applyArm64Ldr(off, s & 0xfff); break;
case IMAGE_REL_ARM64_PAGEOFFSET_12L: applyArm64Ldr(sym_name + "@" + this->file->getName(), off, s & 0xfff); break;
case IMAGE_REL_ARM64_BRANCH26: applyArm64Branch26(off, s - p); break;
case IMAGE_REL_ARM64_BRANCH19: applyArm64Branch19(off, s - p); break;
case IMAGE_REL_ARM64_BRANCH14: applyArm64Branch14(off, s - p); break;
Expand All @@ -344,13 +355,13 @@ void SectionChunk::applyRelARM64(uint8_t *off, uint16_t type, OutputSection *os,
case IMAGE_REL_ARM64_SECREL: applySecRel(this, off, os, s); break;
case IMAGE_REL_ARM64_SECREL_LOW12A: applySecRelLow12A(this, off, os, s); break;
case IMAGE_REL_ARM64_SECREL_HIGH12A: applySecRelHigh12A(this, off, os, s); break;
case IMAGE_REL_ARM64_SECREL_LOW12L: applySecRelLdr(this, off, os, s); break;
case IMAGE_REL_ARM64_SECREL_LOW12L: applySecRelLdr(this, sym_name + "@" + this->file->getName(), off, os, s); break;
case IMAGE_REL_ARM64_SECTION:
applySecIdx(off, os, file->symtab.ctx.outputSections.size());
break;
case IMAGE_REL_ARM64_REL32: add32(off, s - p - 4); break;
default:
error("unsupported relocation type 0x" + Twine::utohexstr(type) + " in " +
error("unsupported relocation type 0x" + Twine::utohexstr(rel.Type) + " in " +
toString(file));
}
}
Expand All @@ -368,6 +379,7 @@ static void maybeReportRelocationToDiscarded(const SectionChunk *fromChunk,

// Get the name of the symbol. If it's null, it was discarded early, so we
// have to go back to the object file.
// COPY TO: SectionChunk::applyRelARM64.
ObjFile *file = fromChunk->file;
std::string name;
if (sym) {
Expand Down Expand Up @@ -457,7 +469,7 @@ void SectionChunk::applyRelocation(uint8_t *off,
applyRelARM(off, rel.Type, os, s, p, imageBase);
break;
case Triple::aarch64:
applyRelARM64(off, rel.Type, os, s, p, imageBase);
applyRelARM64(off, rel, os, s, p, imageBase);
break;
default:
llvm_unreachable("unknown machine type");
Expand Down Expand Up @@ -829,10 +841,17 @@ void ImportThunkChunkARM::writeTo(uint8_t *buf) const {
}

void ImportThunkChunkARM64::writeTo(uint8_t *buf) const {
int64_t off = impSymbol->getRVA() & 0xfff;
memcpy(buf, importThunkARM64, sizeof(importThunkARM64));
applyArm64Addr(buf, impSymbol->getRVA(), rva, 12);
applyArm64Ldr(buf + 4, off);

StringRef fileName;
if (isa<DefinedImportData>(impSymbol))
fileName = static_cast<DefinedImportData *>(impSymbol)->getDLLName();
else
fileName = "<not_defined_import_data>";

int64_t off = impSymbol->getRVA() & 0xfff;
applyArm64Ldr(impSymbol->getName() + "@" + fileName, buf + 4, off);
}

// A Thumb2, PIC, non-interworking range extension thunk.
Expand Down
2 changes: 1 addition & 1 deletion lld/COFF/Chunks.h
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Expand Up @@ -280,7 +280,7 @@ class SectionChunk : public Chunk {
uint64_t p, uint64_t imageBase) const;
void applyRelARM(uint8_t *off, uint16_t type, OutputSection *os, uint64_t s,
uint64_t p, uint64_t imageBase) const;
void applyRelARM64(uint8_t *off, uint16_t type, OutputSection *os, uint64_t s,
void applyRelARM64(uint8_t *off, const coff_relocation &rel, OutputSection *os, uint64_t s,
uint64_t p, uint64_t imageBase) const;

void getRuntimePseudoRelocs(std::vector<RuntimePseudoReloc> &res);
Expand Down