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lld: Put the header in the first PT_LOAD even if that PT_LOAD has a LMAExpr

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The root problem is that we were creating a PT_LOAD just for the header.
That was technically valid, but inconvenient: we should not be making
the ELF discontinuous.

The solution is to allow a section with LMAExpr to be added to a PT_LOAD
if that PT_LOAD doesn't already have a LMAExpr.

LLVM PR:	36017
Obtained from:	LLVM r323625 by Rafael Espindola
This commit is contained in:
Ed Maste 2018-01-29 13:55:50 +00:00
parent 1da0355521
commit 54a6825c80
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=328548
2 changed files with 10 additions and 2 deletions
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7
contrib/llvm/tools/lld/ELF/Writer.cpp
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@ -822,6 +822,8 @@ void PhdrEntry::add(OutputSection *Sec) {
p_align = std::max(p_align, Sec->Alignment);
if (p_type == PT_LOAD)
Sec->PtLoad = this;
if (Sec->LMAExpr)
ASectionHasLMA = true;
}
// The beginning and the ending of .rel[a].plt section are marked
@ -1626,8 +1628,9 @@ template <class ELFT> std::vector<PhdrEntry *> Writer<ELFT>::createPhdrs() {
// different flags or is loaded at a discontiguous address using AT linker
// script command.
uint64_t NewFlags = computeFlags(Sec->getPhdrFlags());
if (Sec->LMAExpr || Sec->MemRegion != Load->FirstSec->MemRegion ||
Flags != NewFlags) {
if ((Sec->LMAExpr && Load->ASectionHasLMA) ||
Sec->MemRegion != Load->FirstSec->MemRegion || Flags != NewFlags) {
Load = AddHdr(PT_LOAD, NewFlags);
Flags = NewFlags;
}

5
contrib/llvm/tools/lld/ELF/Writer.h
View File

@ -44,6 +44,11 @@ struct PhdrEntry {
OutputSection *FirstSec = nullptr;
OutputSection *LastSec = nullptr;
bool HasLMA = false;
// True if any of the sections in this program header as a LMA specified via
// linker script: AT(addr).
bool ASectionHasLMA = false;
uint64_t LMAOffset = 0;
};