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Split Writer::assignAddresses. NFC. 

llvm-svn: 264905
This commit is contained in:
Rui Ueyama 2016-03-30 19:41:51 +00:00
parent 2e0ff2b244
commit 4709190376
2 changed files with 29 additions and 18 deletions
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4
lld/ELF/OutputSections.h
View File

@ -83,6 +83,10 @@ public:
Header.sh_addralign = Align;
}
// If true, this section will be page aligned on disk.
// Typically the first section of each PT_LOAD segment has this flag.
bool PageAlign = false;
virtual void finalize() {}
virtual void writeTo(uint8_t *Buf) {}
virtual ~OutputSectionBase() = default;

43
lld/ELF/Writer.cpp
View File

@ -71,6 +71,7 @@ private:
void createPhdrs();
void assignAddresses();
void assignAddressesRelocatable();
void fixSectionAlignments();
void fixAbsoluteSymbols();
bool openFile();
void writeHeader();
@ -212,6 +213,7 @@ template <class ELFT> void Writer<ELFT>::run() {
return;
if (!Config->Relocatable) {
createPhdrs();
fixSectionAlignments();
assignAddresses();
} else {
assignAddressesRelocatable();
@ -1304,6 +1306,28 @@ template <class ELFT> void Writer<ELFT>::createPhdrs() {
Phdrs.push_back(std::move(Note));
}
// The first section of each PT_LOAD and the first section after PT_GNU_RELRO
// have to be page aligned so that the dynamic linker can set the permissions.
template <class ELFT> void Writer<ELFT>::fixSectionAlignments() {
for (const Phdr &P : Phdrs)
if (P.H.p_type == PT_LOAD)
P.First->PageAlign = true;
for (const Phdr &P : Phdrs) {
if (P.H.p_type != PT_GNU_RELRO)
continue;
// Find the first section after PT_GNU_RELRO. If it is in a PT_LOAD we
// have to align it to a page.
auto End = OutputSections.end();
auto I = std::find(OutputSections.begin(), End, P.Last);
if (I == End || (I + 1) == End)
continue;
OutputSectionBase<ELFT> *Sec = *(I + 1);
if (needsPtLoad(Sec))
Sec->PageAlign = true;
}
}
// Used for relocatable output (-r). In this case we create only ELF file
// header, do not create program headers. Also assign of section addresses
// is very straightforward: we just put all sections sequentually to the file.
@ -1328,30 +1352,13 @@ template <class ELFT> void Writer<ELFT>::assignAddresses() {
size_t PhdrSize = sizeof(Elf_Phdr) * Phdrs.size();
Out<ELFT>::ProgramHeaders->setSize(PhdrSize);
// The first section of each PT_LOAD and the first section after PT_GNU_RELRO
// have to be page aligned so that the dynamic linker can set the permissions.
SmallPtrSet<OutputSectionBase<ELFT> *, 4> PageAlign;
for (const Phdr &P : Phdrs) {
if (P.H.p_type == PT_GNU_RELRO) {
// Find the first section after PT_GNU_RELRO. If it is in a PT_LOAD we
// have to align it to a page.
auto I = std::find(OutputSections.begin(), OutputSections.end(), P.Last);
++I;
if (I != OutputSections.end() && needsPtLoad(*I))
PageAlign.insert(*I);
}
if (P.H.p_type == PT_LOAD)
PageAlign.insert(P.First);
}
uintX_t ThreadBssOffset = 0;
uintX_t VA = Target->getVAStart();
uintX_t FileOff = 0;
for (OutputSectionBase<ELFT> *Sec : OutputSections) {
uintX_t Align = Sec->getAlign();
if (PageAlign.count(Sec))
if (Sec->PageAlign)
Align = std::max<uintX_t>(Align, Target->PageSize);
if (Sec->getType() != SHT_NOBITS)