forked from OSchip/llvm-project
117 lines
4.2 KiB
C++
117 lines
4.2 KiB
C++
//===--------- DefineExternalSectionStartAndEndSymbols.h --------*- C++ -*-===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Utility class for recognizing external section start and end symbols and
|
|
// transforming them into defined symbols for the start and end blocks of the
|
|
// associated Section.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_EXECUTIONENGINE_JITLINK_DEFINEEXTERNALSECTIONSTARTANDENDSYMBOLS_H
|
|
#define LLVM_EXECUTIONENGINE_JITLINK_DEFINEEXTERNALSECTIONSTARTANDENDSYMBOLS_H
|
|
|
|
#include "llvm/ExecutionEngine/JITLink/JITLink.h"
|
|
#include "llvm/Support/Debug.h"
|
|
|
|
#define DEBUG_TYPE "jitlink"
|
|
|
|
namespace llvm {
|
|
namespace jitlink {
|
|
|
|
struct SectionRangeSymbolDesc {
|
|
SectionRangeSymbolDesc() = default;
|
|
SectionRangeSymbolDesc(Section &Sec, bool IsStart)
|
|
: Sec(&Sec), IsStart(IsStart) {}
|
|
Section *Sec = nullptr;
|
|
bool IsStart = false;
|
|
};
|
|
|
|
/// Pass implementation for the createDefineExternalSectionStartAndEndSymbols
|
|
/// function.
|
|
template <typename SymbolIdentifierFunction>
|
|
class DefineExternalSectionStartAndEndSymbols {
|
|
public:
|
|
DefineExternalSectionStartAndEndSymbols(SymbolIdentifierFunction F)
|
|
: F(std::move(F)) {}
|
|
|
|
Error operator()(LinkGraph &G) {
|
|
|
|
// This pass will affect the external symbols set, so copy them out into a
|
|
// vector and iterate over that.
|
|
std::vector<Symbol *> Externals(G.external_symbols().begin(),
|
|
G.external_symbols().end());
|
|
|
|
for (auto *Sym : Externals) {
|
|
SectionRangeSymbolDesc D = F(G, *Sym);
|
|
if (D.Sec) {
|
|
auto &SR = getSectionRange(*D.Sec);
|
|
if (D.IsStart) {
|
|
if (SR.empty())
|
|
G.makeAbsolute(*Sym, 0);
|
|
else
|
|
G.makeDefined(*Sym, *SR.getFirstBlock(), 0, 0, Linkage::Strong,
|
|
Scope::Local, false);
|
|
} else {
|
|
if (SR.empty())
|
|
G.makeAbsolute(*Sym, 0);
|
|
else
|
|
G.makeDefined(*Sym, *SR.getLastBlock(),
|
|
SR.getLastBlock()->getSize(), 0, Linkage::Strong,
|
|
Scope::Local, false);
|
|
}
|
|
}
|
|
}
|
|
return Error::success();
|
|
}
|
|
|
|
private:
|
|
SectionRange &getSectionRange(Section &Sec) {
|
|
auto I = SectionRanges.find(&Sec);
|
|
if (I == SectionRanges.end())
|
|
I = SectionRanges.insert(std::make_pair(&Sec, SectionRange(Sec))).first;
|
|
return I->second;
|
|
}
|
|
|
|
DenseMap<Section *, SectionRange> SectionRanges;
|
|
SymbolIdentifierFunction F;
|
|
};
|
|
|
|
/// Returns a JITLink pass (as a function class) that uses the given symbol
|
|
/// identification function to identify external section start and end symbols
|
|
/// (and their associated Section*s) and transform the identified externals
|
|
/// into defined symbols pointing to the start of the first block in the
|
|
/// section and the end of the last (start and end symbols for empty sections
|
|
/// will be transformed into absolute symbols at address 0).
|
|
///
|
|
/// The identification function should be callable as
|
|
///
|
|
/// SectionRangeSymbolDesc (LinkGraph &G, Symbol &Sym)
|
|
///
|
|
/// If Sym is not a section range start or end symbol then a default
|
|
/// constructed SectionRangeSymbolDesc should be returned. If Sym is a start
|
|
/// symbol then SectionRangeSymbolDesc(Sec, true), where Sec is a reference to
|
|
/// the target Section. If Sym is an end symbol then
|
|
/// SectionRangeSymbolDesc(Sec, false) should be returned.
|
|
///
|
|
/// This pass should be run in the PostAllocationPass pipeline, at which point
|
|
/// all blocks should have been assigned their final addresses.
|
|
template <typename SymbolIdentifierFunction>
|
|
DefineExternalSectionStartAndEndSymbols<SymbolIdentifierFunction>
|
|
createDefineExternalSectionStartAndEndSymbolsPass(
|
|
SymbolIdentifierFunction &&F) {
|
|
return DefineExternalSectionStartAndEndSymbols<SymbolIdentifierFunction>(
|
|
std::forward<SymbolIdentifierFunction>(F));
|
|
}
|
|
|
|
} // end namespace jitlink
|
|
} // end namespace llvm
|
|
|
|
#undef DEBUG_TYPE
|
|
|
|
#endif // LLVM_EXECUTIONENGINE_JITLINK_DEFINEEXTERNALSECTIONSTARTANDENDSYMBOLS_H
|