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[ELF] Simplify assignFileOffsets 

There is a difference with non-SHF_ALLOC SHT_NOBITS when off%sh_addralign!=0
which doesn't happen/matter in practice.
This commit is contained in:
Fangrui Song 2021-11-28 13:44:41 -08:00
parent f5a9bfdf8f
commit cecc6893a0
1 changed files with 9 additions and 15 deletions
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24
lld/ELF/Writer.cpp
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@ -2549,17 +2549,6 @@ static uint64_t computeFileOffset(OutputSection *os, uint64_t off) {
return first->offset + os->addr - first->addr; return first->offset + os->addr - first->addr;
} }
// Set an in-file position to a given section and returns the end position of
// the section.
static uint64_t setFileOffset(OutputSection *os, uint64_t off) {
off = computeFileOffset(os, off);
os->offset = off;
if (os->type == SHT_NOBITS)
return off;
return off + os->size;
}
template <class ELFT> void Writer<ELFT>::assignFileOffsetsBinary() { template <class ELFT> void Writer<ELFT>::assignFileOffsetsBinary() {
// Compute the minimum LMA of all non-empty non-NOBITS sections as minAddr. // Compute the minimum LMA of all non-empty non-NOBITS sections as minAddr.
auto needsOffset = [](OutputSection &sec) { auto needsOffset = [](OutputSection &sec) {
@ -2601,7 +2590,10 @@ template <class ELFT> void Writer<ELFT>::assignFileOffsets() {
for (OutputSection *sec : outputSections) { for (OutputSection *sec : outputSections) {
if (!(sec->flags & SHF_ALLOC)) if (!(sec->flags & SHF_ALLOC))
continue; continue;
off = setFileOffset(sec, off); off = computeFileOffset(sec, off);
sec->offset = off;
if (sec->type != SHT_NOBITS)
off += sec->size;
// If this is a last section of the last executable segment and that // If this is a last section of the last executable segment and that
// segment is the last loadable segment, align the offset of the // segment is the last loadable segment, align the offset of the
@ -2610,9 +2602,11 @@ template <class ELFT> void Writer<ELFT>::assignFileOffsets() {
lastRX->lastSec == sec) lastRX->lastSec == sec)
off = alignTo(off, config->maxPageSize); off = alignTo(off, config->maxPageSize);
} }
for (OutputSection *sec : outputSections) for (OutputSection *osec : outputSections)
if (!(sec->flags & SHF_ALLOC)) if (!(osec->flags & SHF_ALLOC)) {
off = setFileOffset(sec, off); osec->offset = alignTo(off, osec->alignment);
off = osec->offset + osec->size;
}
sectionHeaderOff = alignTo(off, config->wordsize); sectionHeaderOff = alignTo(off, config->wordsize);
fileSize = sectionHeaderOff + (outputSections.size() + 1) * sizeof(Elf_Shdr); fileSize = sectionHeaderOff + (outputSections.size() + 1) * sizeof(Elf_Shdr);