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[ELF] Allow multiple thunks to be added for a symbol. 

This change permits there to be more than one thunk to be associated with
a symbol. For interworking thunks we only require one thunk, but range
extension thunks may require more than one.

Differential Revision: https://reviews.llvm.org/D34037

llvm-svn: 307136
This commit is contained in:
Peter Smith 2017-07-05 09:53:33 +00:00
parent ebe56283bc
commit fa23764278
2 changed files with 17 additions and 7 deletions
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15
lld/ELF/Relocations.cpp
View File

@ -1049,10 +1049,17 @@ ThunkSection *ThunkCreator::addThunkSection(OutputSection *OS,
std::pair<Thunk *, bool> ThunkCreator::getThunk(SymbolBody &Body,
uint32_t Type) {
auto res = ThunkedSymbols.insert({&Body, nullptr});
if (res.second || !res.first->second->isCompatibleWith(Type))
res.first->second = addThunk(Type, Body);
return std::make_pair(res.first->second, res.second);
auto Res = ThunkedSymbols.insert({&Body, std::vector<Thunk *>()});
if (!Res.second) {
// Check existing Thunks for Body to see if they can be reused
for (Thunk *ET : Res.first->second)
if (ET->isCompatibleWith(Type))
return {ET, false};
}
// No existing compatible Thunk in range, create a new one
Thunk *T = addThunk(Type, Body);
Res.first->second.push_back(T);
return {T, true};
}
// Call Fn on every executable InputSection accessed via the linker script

9
lld/ELF/Relocations.h
View File

@ -144,14 +144,17 @@ private:
std::pair<Thunk *, bool> getThunk(SymbolBody &Body, uint32_t Type);
ThunkSection *addThunkSection(OutputSection *OS,
std::vector<InputSection *> *, uint64_t Off);
// Track Symbols that already have a Thunk
llvm::DenseMap<SymbolBody *, Thunk *> ThunkedSymbols;
// Record all the available Thunks for a Symbol
llvm::DenseMap<SymbolBody *, std::vector<Thunk *>> ThunkedSymbols;
// Find a Thunk from the Thunks symbol definition, we can use this to find
// the Thunk from a relocation to the Thunks symbol definition.
llvm::DenseMap<SymbolBody *, Thunk *> Thunks;
// Track InputSections that have a ThunkSection placed in front
// Track InputSections that have an inline ThunkSection placed in front
// an inline ThunkSection may have control fall through to the section below
// so we need to make sure that there is only one of them.
// The Mips LA25 Thunk is an example of an inline ThunkSection.
llvm::DenseMap<InputSection *, ThunkSection *> ThunkedSections;
// All the ThunkSections that we have created, organised by OutputSection