llvm-6502/include/llvm/LTO/LTOModule.h
Peter Collingbourne a6367d9136 Teach LTOModule to emit linker flags for dllexported symbols, plus interface cleanup.
This change unifies how LTOModule and the backend obtain linker flags
for globals: via a new TargetLoweringObjectFile member function named
emitLinkerFlagsForGlobal. A new function LTOModule::getLinkerOpts() returns
the list of linker flags as a single concatenated string.

This change affects the C libLTO API: the function lto_module_get_*deplibs now
exposes an empty list, and lto_module_get_*linkeropts exposes a single element
which combines the contents of all observed flags. libLTO should never have
tried to parse the linker flags; it is the linker's job to do so. Because
linkers will need to be able to parse flags in regular object files, it
makes little sense for libLTO to have a redundant mechanism for doing so.

The new API is compatible with the old one. It is valid for a user to specify
multiple linker flags in a single pragma directive like this:

 #pragma comment(linker, "/defaultlib:foo /defaultlib:bar")

The previous implementation would not have exposed
either flag via lto_module_get_*deplibs (as the test in
TargetLoweringObjectFileCOFF::getDepLibFromLinkerOpt was case sensitive)
and would have exposed "/defaultlib:foo /defaultlib:bar" as a single flag via
lto_module_get_*linkeropts. This may have been a bug in the implementation,
but it does give us a chance to fix the interface.

Differential Revision: http://reviews.llvm.org/D10548

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241010 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-29 22:04:09 +00:00

208 lines
7.2 KiB
C++

//===-LTOModule.h - LLVM Link Time Optimizer ------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the LTOModule class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LTO_LTOMODULE_H
#define LLVM_LTO_LTOMODULE_H
#include "llvm-c/lto.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/Object/IRObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include <string>
#include <vector>
// Forward references to llvm classes.
namespace llvm {
class Function;
class GlobalValue;
class MemoryBuffer;
class TargetOptions;
class Value;
//===----------------------------------------------------------------------===//
/// C++ class which implements the opaque lto_module_t type.
///
struct LTOModule {
private:
struct NameAndAttributes {
const char *name;
uint32_t attributes;
bool isFunction;
const GlobalValue *symbol;
};
std::unique_ptr<LLVMContext> OwnedContext;
std::string LinkerOpts;
std::unique_ptr<object::IRObjectFile> IRFile;
std::unique_ptr<TargetMachine> _target;
std::vector<NameAndAttributes> _symbols;
// _defines and _undefines only needed to disambiguate tentative definitions
StringSet<> _defines;
StringMap<NameAndAttributes> _undefines;
std::vector<const char*> _asm_undefines;
LTOModule(std::unique_ptr<object::IRObjectFile> Obj, TargetMachine *TM);
LTOModule(std::unique_ptr<object::IRObjectFile> Obj, TargetMachine *TM,
std::unique_ptr<LLVMContext> Context);
public:
~LTOModule();
/// Returns 'true' if the file or memory contents is LLVM bitcode.
static bool isBitcodeFile(const void *mem, size_t length);
static bool isBitcodeFile(const char *path);
/// Returns 'true' if the memory buffer is LLVM bitcode for the specified
/// triple.
static bool isBitcodeForTarget(MemoryBuffer *memBuffer,
StringRef triplePrefix);
/// Create a MemoryBuffer from a memory range with an optional name.
static std::unique_ptr<MemoryBuffer>
makeBuffer(const void *mem, size_t length, StringRef name = "");
/// Create an LTOModule. N.B. These methods take ownership of the buffer. The
/// caller must have initialized the Targets, the TargetMCs, the AsmPrinters,
/// and the AsmParsers by calling:
///
/// InitializeAllTargets();
/// InitializeAllTargetMCs();
/// InitializeAllAsmPrinters();
/// InitializeAllAsmParsers();
static LTOModule *createFromFile(const char *path, TargetOptions options,
std::string &errMsg);
static LTOModule *createFromOpenFile(int fd, const char *path, size_t size,
TargetOptions options,
std::string &errMsg);
static LTOModule *createFromOpenFileSlice(int fd, const char *path,
size_t map_size, off_t offset,
TargetOptions options,
std::string &errMsg);
static LTOModule *createFromBuffer(const void *mem, size_t length,
TargetOptions options, std::string &errMsg,
StringRef path = "");
static LTOModule *createInLocalContext(const void *mem, size_t length,
TargetOptions options,
std::string &errMsg, StringRef path);
static LTOModule *createInContext(const void *mem, size_t length,
TargetOptions options, std::string &errMsg,
StringRef path, LLVMContext *Context);
const Module &getModule() const {
return const_cast<LTOModule*>(this)->getModule();
}
Module &getModule() {
return IRFile->getModule();
}
/// Return the Module's target triple.
const std::string &getTargetTriple() {
return getModule().getTargetTriple();
}
/// Set the Module's target triple.
void setTargetTriple(StringRef Triple) {
getModule().setTargetTriple(Triple);
}
/// Get the number of symbols
uint32_t getSymbolCount() {
return _symbols.size();
}
/// Get the attributes for a symbol at the specified index.
lto_symbol_attributes getSymbolAttributes(uint32_t index) {
if (index < _symbols.size())
return lto_symbol_attributes(_symbols[index].attributes);
return lto_symbol_attributes(0);
}
/// Get the name of the symbol at the specified index.
const char *getSymbolName(uint32_t index) {
if (index < _symbols.size())
return _symbols[index].name;
return nullptr;
}
const GlobalValue *getSymbolGV(uint32_t index) {
if (index < _symbols.size())
return _symbols[index].symbol;
return nullptr;
}
const char *getLinkerOpts() {
return LinkerOpts.c_str();
}
const std::vector<const char*> &getAsmUndefinedRefs() {
return _asm_undefines;
}
private:
/// Parse metadata from the module
// FIXME: it only parses "Linker Options" metadata at the moment
void parseMetadata();
/// Parse the symbols from the module and model-level ASM and add them to
/// either the defined or undefined lists.
bool parseSymbols(std::string &errMsg);
/// Add a symbol which isn't defined just yet to a list to be resolved later.
void addPotentialUndefinedSymbol(const object::BasicSymbolRef &Sym,
bool isFunc);
/// Add a defined symbol to the list.
void addDefinedSymbol(const char *Name, const GlobalValue *def,
bool isFunction);
/// Add a data symbol as defined to the list.
void addDefinedDataSymbol(const object::BasicSymbolRef &Sym);
void addDefinedDataSymbol(const char*Name, const GlobalValue *v);
/// Add a function symbol as defined to the list.
void addDefinedFunctionSymbol(const object::BasicSymbolRef &Sym);
void addDefinedFunctionSymbol(const char *Name, const Function *F);
/// Add a global symbol from module-level ASM to the defined list.
void addAsmGlobalSymbol(const char *, lto_symbol_attributes scope);
/// Add a global symbol from module-level ASM to the undefined list.
void addAsmGlobalSymbolUndef(const char *);
/// Parse i386/ppc ObjC class data structure.
void addObjCClass(const GlobalVariable *clgv);
/// Parse i386/ppc ObjC category data structure.
void addObjCCategory(const GlobalVariable *clgv);
/// Parse i386/ppc ObjC class list data structure.
void addObjCClassRef(const GlobalVariable *clgv);
/// Get string that the data pointer points to.
bool objcClassNameFromExpression(const Constant *c, std::string &name);
/// Create an LTOModule (private version).
static LTOModule *makeLTOModule(MemoryBufferRef Buffer, TargetOptions options,
std::string &errMsg, LLVMContext *Context);
};
}
#endif