llvm-project/lld/COFF/DriverUtils.cpp

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//===- DriverUtils.cpp ----------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains utility functions for the driver. Because there
// are so many small functions, we created this separate file to make
// Driver.cpp less cluttered.
//
//===----------------------------------------------------------------------===//
#include "Config.h"
#include "Driver.h"
#include "Symbols.h"
#include "lld/Common/ErrorHandler.h"
#include "lld/Common/Memory.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/WindowsResource.h"
#include "llvm/Option/Arg.h"
#include "llvm/Option/ArgList.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/Program.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/WindowsManifest/WindowsManifestMerger.h"
#include <memory>
using namespace llvm::COFF;
using namespace llvm;
using llvm::sys::Process;
namespace lld {
namespace coff {
namespace {
const uint16_t SUBLANG_ENGLISH_US = 0x0409;
const uint16_t RT_MANIFEST = 24;
class Executor {
public:
explicit Executor(StringRef S) : Prog(Saver.save(S)) {}
void add(StringRef S) { Args.push_back(Saver.save(S)); }
void add(std::string &S) { Args.push_back(Saver.save(S)); }
void add(Twine S) { Args.push_back(Saver.save(S)); }
void add(const char *S) { Args.push_back(Saver.save(S)); }
void run() {
ErrorOr<std::string> ExeOrErr = sys::findProgramByName(Prog);
if (auto EC = ExeOrErr.getError())
fatal("unable to find " + Prog + " in PATH: " + EC.message());
StringRef Exe = Saver.save(*ExeOrErr);
Args.insert(Args.begin(), Exe);
std::vector<const char *> Vec;
for (StringRef S : Args)
Vec.push_back(S.data());
Vec.push_back(nullptr);
if (sys::ExecuteAndWait(Args[0], Vec.data()) != 0)
fatal("ExecuteAndWait failed: " +
llvm::join(Args.begin(), Args.end(), " "));
}
private:
StringRef Prog;
std::vector<StringRef> Args;
};
} // anonymous namespace
// Returns /machine's value.
MachineTypes getMachineType(StringRef S) {
MachineTypes MT = StringSwitch<MachineTypes>(S.lower())
.Cases("x64", "amd64", AMD64)
.Cases("x86", "i386", I386)
.Case("arm", ARMNT)
.Case("arm64", ARM64)
.Default(IMAGE_FILE_MACHINE_UNKNOWN);
if (MT != IMAGE_FILE_MACHINE_UNKNOWN)
return MT;
fatal("unknown /machine argument: " + S);
}
StringRef machineToStr(MachineTypes MT) {
switch (MT) {
case ARMNT:
return "arm";
case ARM64:
return "arm64";
case AMD64:
return "x64";
case I386:
return "x86";
default:
llvm_unreachable("unknown machine type");
}
}
// Parses a string in the form of "<integer>[,<integer>]".
void parseNumbers(StringRef Arg, uint64_t *Addr, uint64_t *Size) {
StringRef S1, S2;
std::tie(S1, S2) = Arg.split(',');
if (S1.getAsInteger(0, *Addr))
fatal("invalid number: " + S1);
if (Size && !S2.empty() && S2.getAsInteger(0, *Size))
fatal("invalid number: " + S2);
}
// Parses a string in the form of "<integer>[.<integer>]".
// If second number is not present, Minor is set to 0.
void parseVersion(StringRef Arg, uint32_t *Major, uint32_t *Minor) {
StringRef S1, S2;
std::tie(S1, S2) = Arg.split('.');
if (S1.getAsInteger(0, *Major))
fatal("invalid number: " + S1);
*Minor = 0;
if (!S2.empty() && S2.getAsInteger(0, *Minor))
fatal("invalid number: " + S2);
}
// Parses a string in the form of "<subsystem>[,<integer>[.<integer>]]".
void parseSubsystem(StringRef Arg, WindowsSubsystem *Sys, uint32_t *Major,
uint32_t *Minor) {
StringRef SysStr, Ver;
std::tie(SysStr, Ver) = Arg.split(',');
*Sys = StringSwitch<WindowsSubsystem>(SysStr.lower())
.Case("boot_application", IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION)
.Case("console", IMAGE_SUBSYSTEM_WINDOWS_CUI)
.Case("efi_application", IMAGE_SUBSYSTEM_EFI_APPLICATION)
.Case("efi_boot_service_driver", IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER)
.Case("efi_rom", IMAGE_SUBSYSTEM_EFI_ROM)
.Case("efi_runtime_driver", IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER)
.Case("native", IMAGE_SUBSYSTEM_NATIVE)
.Case("posix", IMAGE_SUBSYSTEM_POSIX_CUI)
.Case("windows", IMAGE_SUBSYSTEM_WINDOWS_GUI)
.Default(IMAGE_SUBSYSTEM_UNKNOWN);
if (*Sys == IMAGE_SUBSYSTEM_UNKNOWN)
fatal("unknown subsystem: " + SysStr);
if (!Ver.empty())
parseVersion(Ver, Major, Minor);
}
// Parse a string of the form of "<from>=<to>".
// Results are directly written to Config.
void parseAlternateName(StringRef S) {
StringRef From, To;
std::tie(From, To) = S.split('=');
if (From.empty() || To.empty())
fatal("/alternatename: invalid argument: " + S);
auto It = Config->AlternateNames.find(From);
if (It != Config->AlternateNames.end() && It->second != To)
fatal("/alternatename: conflicts: " + S);
Config->AlternateNames.insert(It, std::make_pair(From, To));
}
// Parse a string of the form of "<from>=<to>".
// Results are directly written to Config.
void parseMerge(StringRef S) {
StringRef From, To;
std::tie(From, To) = S.split('=');
if (From.empty() || To.empty())
fatal("/merge: invalid argument: " + S);
auto Pair = Config->Merge.insert(std::make_pair(From, To));
bool Inserted = Pair.second;
if (!Inserted) {
StringRef Existing = Pair.first->second;
if (Existing != To)
warn(S + ": already merged into " + Existing);
}
}
static uint32_t parseSectionAttributes(StringRef S) {
uint32_t Ret = 0;
for (char C : S.lower()) {
switch (C) {
case 'd':
Ret |= IMAGE_SCN_MEM_DISCARDABLE;
break;
case 'e':
Ret |= IMAGE_SCN_MEM_EXECUTE;
break;
case 'k':
Ret |= IMAGE_SCN_MEM_NOT_CACHED;
break;
case 'p':
Ret |= IMAGE_SCN_MEM_NOT_PAGED;
break;
case 'r':
Ret |= IMAGE_SCN_MEM_READ;
break;
case 's':
Ret |= IMAGE_SCN_MEM_SHARED;
break;
case 'w':
Ret |= IMAGE_SCN_MEM_WRITE;
break;
default:
fatal("/section: invalid argument: " + S);
}
}
return Ret;
}
// Parses /section option argument.
void parseSection(StringRef S) {
StringRef Name, Attrs;
std::tie(Name, Attrs) = S.split(',');
if (Name.empty() || Attrs.empty())
fatal("/section: invalid argument: " + S);
Config->Section[Name] = parseSectionAttributes(Attrs);
}
// Parses /aligncomm option argument.
void parseAligncomm(StringRef S) {
StringRef Name, Align;
std::tie(Name, Align) = S.split(',');
if (Name.empty() || Align.empty()) {
error("/aligncomm: invalid argument: " + S);
return;
}
int V;
if (Align.getAsInteger(0, V)) {
error("/aligncomm: invalid argument: " + S);
return;
}
Config->AlignComm[Name] = std::max(Config->AlignComm[Name], 1 << V);
}
// Parses a string in the form of "EMBED[,=<integer>]|NO".
// Results are directly written to Config.
void parseManifest(StringRef Arg) {
if (Arg.equals_lower("no")) {
Config->Manifest = Configuration::No;
return;
}
if (!Arg.startswith_lower("embed"))
fatal("invalid option " + Arg);
Config->Manifest = Configuration::Embed;
Arg = Arg.substr(strlen("embed"));
if (Arg.empty())
return;
if (!Arg.startswith_lower(",id="))
fatal("invalid option " + Arg);
Arg = Arg.substr(strlen(",id="));
if (Arg.getAsInteger(0, Config->ManifestID))
fatal("invalid option " + Arg);
}
// Parses a string in the form of "level=<string>|uiAccess=<string>|NO".
// Results are directly written to Config.
void parseManifestUAC(StringRef Arg) {
if (Arg.equals_lower("no")) {
Config->ManifestUAC = false;
return;
}
for (;;) {
Arg = Arg.ltrim();
if (Arg.empty())
return;
if (Arg.startswith_lower("level=")) {
Arg = Arg.substr(strlen("level="));
std::tie(Config->ManifestLevel, Arg) = Arg.split(" ");
continue;
}
if (Arg.startswith_lower("uiaccess=")) {
Arg = Arg.substr(strlen("uiaccess="));
std::tie(Config->ManifestUIAccess, Arg) = Arg.split(" ");
continue;
}
fatal("invalid option " + Arg);
}
}
// An RAII temporary file class that automatically removes a temporary file.
namespace {
class TemporaryFile {
public:
TemporaryFile(StringRef Prefix, StringRef Extn, StringRef Contents = "") {
SmallString<128> S;
if (auto EC = sys::fs::createTemporaryFile("lld-" + Prefix, Extn, S))
fatal("cannot create a temporary file: " + EC.message());
Path = S.str();
if (!Contents.empty()) {
std::error_code EC;
raw_fd_ostream OS(Path, EC, sys::fs::F_None);
if (EC)
fatal("failed to open " + Path + ": " + EC.message());
OS << Contents;
}
}
TemporaryFile(TemporaryFile &&Obj) {
std::swap(Path, Obj.Path);
}
~TemporaryFile() {
if (Path.empty())
return;
if (sys::fs::remove(Path))
fatal("failed to remove " + Path);
}
// Returns a memory buffer of this temporary file.
// Note that this function does not leave the file open,
// so it is safe to remove the file immediately after this function
// is called (you cannot remove an opened file on Windows.)
std::unique_ptr<MemoryBuffer> getMemoryBuffer() {
// IsVolatileSize=true forces MemoryBuffer to not use mmap().
return CHECK(MemoryBuffer::getFile(Path, /*FileSize=*/-1,
/*RequiresNullTerminator=*/false,
/*IsVolatileSize=*/true),
"could not open " + Path);
}
std::string Path;
};
}
static std::string createDefaultXml() {
std::string Ret;
raw_string_ostream OS(Ret);
// Emit the XML. Note that we do *not* verify that the XML attributes are
// syntactically correct. This is intentional for link.exe compatibility.
OS << "<?xml version=\"1.0\" standalone=\"yes\"?>\n"
<< "<assembly xmlns=\"urn:schemas-microsoft-com:asm.v1\"\n"
<< " manifestVersion=\"1.0\">\n";
if (Config->ManifestUAC) {
OS << " <trustInfo>\n"
<< " <security>\n"
<< " <requestedPrivileges>\n"
<< " <requestedExecutionLevel level=" << Config->ManifestLevel
<< " uiAccess=" << Config->ManifestUIAccess << "/>\n"
<< " </requestedPrivileges>\n"
<< " </security>\n"
<< " </trustInfo>\n";
}
if (!Config->ManifestDependency.empty()) {
OS << " <dependency>\n"
<< " <dependentAssembly>\n"
<< " <assemblyIdentity " << Config->ManifestDependency << " />\n"
<< " </dependentAssembly>\n"
<< " </dependency>\n";
}
OS << "</assembly>\n";
return OS.str();
}
static std::string createManifestXmlWithInternalMt(StringRef DefaultXml) {
std::unique_ptr<MemoryBuffer> DefaultXmlCopy =
MemoryBuffer::getMemBufferCopy(DefaultXml);
windows_manifest::WindowsManifestMerger Merger;
if (auto E = Merger.merge(*DefaultXmlCopy.get()))
fatal("internal manifest tool failed on default xml: " +
toString(std::move(E)));
for (StringRef Filename : Config->ManifestInput) {
std::unique_ptr<MemoryBuffer> Manifest =
check(MemoryBuffer::getFile(Filename));
if (auto E = Merger.merge(*Manifest.get()))
fatal("internal manifest tool failed on file " + Filename + ": " +
toString(std::move(E)));
}
return Merger.getMergedManifest().get()->getBuffer();
}
static std::string createManifestXmlWithExternalMt(StringRef DefaultXml) {
// Create the default manifest file as a temporary file.
TemporaryFile Default("defaultxml", "manifest");
std::error_code EC;
raw_fd_ostream OS(Default.Path, EC, sys::fs::F_Text);
if (EC)
fatal("failed to open " + Default.Path + ": " + EC.message());
OS << DefaultXml;
OS.close();
// Merge user-supplied manifests if they are given. Since libxml2 is not
// enabled, we must shell out to Microsoft's mt.exe tool.
TemporaryFile User("user", "manifest");
Executor E("mt.exe");
E.add("/manifest");
E.add(Default.Path);
for (StringRef Filename : Config->ManifestInput) {
E.add("/manifest");
E.add(Filename);
}
E.add("/nologo");
E.add("/out:" + StringRef(User.Path));
E.run();
return CHECK(MemoryBuffer::getFile(User.Path), "could not open " + User.Path)
.get()
->getBuffer();
}
static std::string createManifestXml() {
std::string DefaultXml = createDefaultXml();
if (Config->ManifestInput.empty())
return DefaultXml;
if (windows_manifest::isAvailable())
return createManifestXmlWithInternalMt(DefaultXml);
return createManifestXmlWithExternalMt(DefaultXml);
}
static std::unique_ptr<WritableMemoryBuffer>
createMemoryBufferForManifestRes(size_t ManifestSize) {
size_t ResSize = alignTo(
object::WIN_RES_MAGIC_SIZE + object::WIN_RES_NULL_ENTRY_SIZE +
sizeof(object::WinResHeaderPrefix) + sizeof(object::WinResIDs) +
sizeof(object::WinResHeaderSuffix) + ManifestSize,
object::WIN_RES_DATA_ALIGNMENT);
return WritableMemoryBuffer::getNewMemBuffer(ResSize, Config->OutputFile +
".manifest.res");
}
static void writeResFileHeader(char *&Buf) {
memcpy(Buf, COFF::WinResMagic, sizeof(COFF::WinResMagic));
Buf += sizeof(COFF::WinResMagic);
memset(Buf, 0, object::WIN_RES_NULL_ENTRY_SIZE);
Buf += object::WIN_RES_NULL_ENTRY_SIZE;
}
static void writeResEntryHeader(char *&Buf, size_t ManifestSize) {
// Write the prefix.
auto *Prefix = reinterpret_cast<object::WinResHeaderPrefix *>(Buf);
Prefix->DataSize = ManifestSize;
Prefix->HeaderSize = sizeof(object::WinResHeaderPrefix) +
sizeof(object::WinResIDs) +
sizeof(object::WinResHeaderSuffix);
Buf += sizeof(object::WinResHeaderPrefix);
// Write the Type/Name IDs.
auto *IDs = reinterpret_cast<object::WinResIDs *>(Buf);
IDs->setType(RT_MANIFEST);
IDs->setName(Config->ManifestID);
Buf += sizeof(object::WinResIDs);
// Write the suffix.
auto *Suffix = reinterpret_cast<object::WinResHeaderSuffix *>(Buf);
Suffix->DataVersion = 0;
Suffix->MemoryFlags = object::WIN_RES_PURE_MOVEABLE;
Suffix->Language = SUBLANG_ENGLISH_US;
Suffix->Version = 0;
Suffix->Characteristics = 0;
Buf += sizeof(object::WinResHeaderSuffix);
}
// Create a resource file containing a manifest XML.
std::unique_ptr<MemoryBuffer> createManifestRes() {
std::string Manifest = createManifestXml();
std::unique_ptr<WritableMemoryBuffer> Res =
createMemoryBufferForManifestRes(Manifest.size());
char *Buf = Res->getBufferStart();
writeResFileHeader(Buf);
writeResEntryHeader(Buf, Manifest.size());
// Copy the manifest data into the .res file.
std::copy(Manifest.begin(), Manifest.end(), Buf);
return Res;
}
void createSideBySideManifest() {
std::string Path = Config->ManifestFile;
if (Path == "")
Path = Config->OutputFile + ".manifest";
std::error_code EC;
raw_fd_ostream Out(Path, EC, sys::fs::F_Text);
if (EC)
fatal("failed to create manifest: " + EC.message());
Out << createManifestXml();
}
// Parse a string in the form of
// "<name>[=<internalname>][,@ordinal[,NONAME]][,DATA][,PRIVATE]"
// or "<name>=<dllname>.<name>".
// Used for parsing /export arguments.
Export parseExport(StringRef Arg) {
Export E;
StringRef Rest;
std::tie(E.Name, Rest) = Arg.split(",");
if (E.Name.empty())
goto err;
if (E.Name.contains('=')) {
StringRef X, Y;
std::tie(X, Y) = E.Name.split("=");
// If "<name>=<dllname>.<name>".
if (Y.contains(".")) {
E.Name = X;
E.ForwardTo = Y;
return E;
}
E.ExtName = X;
E.Name = Y;
if (E.Name.empty())
goto err;
}
// If "<name>=<internalname>[,@ordinal[,NONAME]][,DATA][,PRIVATE]"
while (!Rest.empty()) {
StringRef Tok;
std::tie(Tok, Rest) = Rest.split(",");
if (Tok.equals_lower("noname")) {
if (E.Ordinal == 0)
goto err;
E.Noname = true;
continue;
}
if (Tok.equals_lower("data")) {
E.Data = true;
continue;
}
if (Tok.equals_lower("constant")) {
E.Constant = true;
continue;
}
if (Tok.equals_lower("private")) {
E.Private = true;
continue;
}
if (Tok.startswith("@")) {
int32_t Ord;
if (Tok.substr(1).getAsInteger(0, Ord))
goto err;
if (Ord <= 0 || 65535 < Ord)
goto err;
E.Ordinal = Ord;
continue;
}
goto err;
}
return E;
err:
fatal("invalid /export: " + Arg);
}
COFF: Improve dllexported name mangling compatibility. The rules for dllexported symbols are overly complicated due to x86 name decoration, fuzzy symbol resolution, and the fact that one symbol can be resolved by so many different names. The rules are probably intended to be "intuitive", so that users don't have to understand the name mangling schemes, but it seems that it can lead to unintended symbol exports. To make it clear what I'm trying to do with this patch, let me write how the export rules are subtle and complicated. - x86 name decoration: If machine type is i386 and export name is given by a command line option, like /export:foo, the real symbol name the linker has to search for is _foo because all symbols are decorated with "_" prefixes. This doesn't happen on non-x86 machines. This automatic name decoration happens only when the name is not C++ mangled. However, the symbol name exported from DLLs are ones without "_" on all platforms. Moreover, if the option is given via .drectve section, no symbol decoration is done (the reason being that the .drectve section is created by a compiler and the compiler should always know the exact name of the symbol, I guess). - Fuzzy symbol resolution: In addition to x86 name decoration, the linker has to look for cdecl or C++ mangled symbols for a given /export. For example, it searches for not only _foo but also _foo@<number> or ??foo@... for /export:foo. Previous implementation didn't get it right. I'm trying to make it as compatible with MSVC linker as possible with this patch however the rules are. The new code looks a bit messy to me, but I don't think it can be simpler due to the ad-hoc-ness of the rules. llvm-svn: 246424
2015-08-31 16:43:21 +08:00
static StringRef undecorate(StringRef Sym) {
if (Config->Machine != I386)
return Sym;
return Sym.startswith("_") ? Sym.substr(1) : Sym;
}
// Performs error checking on all /export arguments.
// It also sets ordinals.
void fixupExports() {
// Symbol ordinals must be unique.
std::set<uint16_t> Ords;
for (Export &E : Config->Exports) {
if (E.Ordinal == 0)
continue;
if (!Ords.insert(E.Ordinal).second)
fatal("duplicate export ordinal: " + E.Name);
}
for (Export &E : Config->Exports) {
Symbol *Sym = E.Sym;
if (!E.ForwardTo.empty() || !Sym) {
E.SymbolName = E.Name;
} else {
if (auto *U = dyn_cast<Undefined>(Sym))
if (U->WeakAlias)
Sym = U->WeakAlias;
E.SymbolName = Sym->getName();
}
}
for (Export &E : Config->Exports) {
if (!E.ForwardTo.empty()) {
E.ExportName = undecorate(E.Name);
} else {
E.ExportName = undecorate(E.ExtName.empty() ? E.Name : E.ExtName);
}
}
COFF: Improve dllexported name mangling compatibility. The rules for dllexported symbols are overly complicated due to x86 name decoration, fuzzy symbol resolution, and the fact that one symbol can be resolved by so many different names. The rules are probably intended to be "intuitive", so that users don't have to understand the name mangling schemes, but it seems that it can lead to unintended symbol exports. To make it clear what I'm trying to do with this patch, let me write how the export rules are subtle and complicated. - x86 name decoration: If machine type is i386 and export name is given by a command line option, like /export:foo, the real symbol name the linker has to search for is _foo because all symbols are decorated with "_" prefixes. This doesn't happen on non-x86 machines. This automatic name decoration happens only when the name is not C++ mangled. However, the symbol name exported from DLLs are ones without "_" on all platforms. Moreover, if the option is given via .drectve section, no symbol decoration is done (the reason being that the .drectve section is created by a compiler and the compiler should always know the exact name of the symbol, I guess). - Fuzzy symbol resolution: In addition to x86 name decoration, the linker has to look for cdecl or C++ mangled symbols for a given /export. For example, it searches for not only _foo but also _foo@<number> or ??foo@... for /export:foo. Previous implementation didn't get it right. I'm trying to make it as compatible with MSVC linker as possible with this patch however the rules are. The new code looks a bit messy to me, but I don't think it can be simpler due to the ad-hoc-ness of the rules. llvm-svn: 246424
2015-08-31 16:43:21 +08:00
// Uniquefy by name.
DenseMap<StringRef, Export *> Map(Config->Exports.size());
std::vector<Export> V;
for (Export &E : Config->Exports) {
COFF: Improve dllexported name mangling compatibility. The rules for dllexported symbols are overly complicated due to x86 name decoration, fuzzy symbol resolution, and the fact that one symbol can be resolved by so many different names. The rules are probably intended to be "intuitive", so that users don't have to understand the name mangling schemes, but it seems that it can lead to unintended symbol exports. To make it clear what I'm trying to do with this patch, let me write how the export rules are subtle and complicated. - x86 name decoration: If machine type is i386 and export name is given by a command line option, like /export:foo, the real symbol name the linker has to search for is _foo because all symbols are decorated with "_" prefixes. This doesn't happen on non-x86 machines. This automatic name decoration happens only when the name is not C++ mangled. However, the symbol name exported from DLLs are ones without "_" on all platforms. Moreover, if the option is given via .drectve section, no symbol decoration is done (the reason being that the .drectve section is created by a compiler and the compiler should always know the exact name of the symbol, I guess). - Fuzzy symbol resolution: In addition to x86 name decoration, the linker has to look for cdecl or C++ mangled symbols for a given /export. For example, it searches for not only _foo but also _foo@<number> or ??foo@... for /export:foo. Previous implementation didn't get it right. I'm trying to make it as compatible with MSVC linker as possible with this patch however the rules are. The new code looks a bit messy to me, but I don't think it can be simpler due to the ad-hoc-ness of the rules. llvm-svn: 246424
2015-08-31 16:43:21 +08:00
auto Pair = Map.insert(std::make_pair(E.ExportName, &E));
bool Inserted = Pair.second;
if (Inserted) {
V.push_back(E);
continue;
}
Export *Existing = Pair.first->second;
if (E == *Existing || E.Name != Existing->Name)
continue;
warn("duplicate /export option: " + E.Name);
}
Config->Exports = std::move(V);
// Sort by name.
std::sort(Config->Exports.begin(), Config->Exports.end(),
[](const Export &A, const Export &B) {
COFF: Improve dllexported name mangling compatibility. The rules for dllexported symbols are overly complicated due to x86 name decoration, fuzzy symbol resolution, and the fact that one symbol can be resolved by so many different names. The rules are probably intended to be "intuitive", so that users don't have to understand the name mangling schemes, but it seems that it can lead to unintended symbol exports. To make it clear what I'm trying to do with this patch, let me write how the export rules are subtle and complicated. - x86 name decoration: If machine type is i386 and export name is given by a command line option, like /export:foo, the real symbol name the linker has to search for is _foo because all symbols are decorated with "_" prefixes. This doesn't happen on non-x86 machines. This automatic name decoration happens only when the name is not C++ mangled. However, the symbol name exported from DLLs are ones without "_" on all platforms. Moreover, if the option is given via .drectve section, no symbol decoration is done (the reason being that the .drectve section is created by a compiler and the compiler should always know the exact name of the symbol, I guess). - Fuzzy symbol resolution: In addition to x86 name decoration, the linker has to look for cdecl or C++ mangled symbols for a given /export. For example, it searches for not only _foo but also _foo@<number> or ??foo@... for /export:foo. Previous implementation didn't get it right. I'm trying to make it as compatible with MSVC linker as possible with this patch however the rules are. The new code looks a bit messy to me, but I don't think it can be simpler due to the ad-hoc-ness of the rules. llvm-svn: 246424
2015-08-31 16:43:21 +08:00
return A.ExportName < B.ExportName;
});
}
void assignExportOrdinals() {
// Assign unique ordinals if default (= 0).
uint16_t Max = 0;
for (Export &E : Config->Exports)
Max = std::max(Max, E.Ordinal);
for (Export &E : Config->Exports)
if (E.Ordinal == 0)
E.Ordinal = ++Max;
}
// Parses a string in the form of "key=value" and check
// if value matches previous values for the same key.
void checkFailIfMismatch(StringRef Arg) {
StringRef K, V;
std::tie(K, V) = Arg.split('=');
if (K.empty() || V.empty())
fatal("/failifmismatch: invalid argument: " + Arg);
StringRef Existing = Config->MustMatch[K];
if (!Existing.empty() && V != Existing)
fatal("/failifmismatch: mismatch detected: " + Existing + " and " + V +
" for key " + K);
Config->MustMatch[K] = V;
}
// Convert Windows resource files (.res files) to a .obj file.
MemoryBufferRef convertResToCOFF(ArrayRef<MemoryBufferRef> MBs) {
object::WindowsResourceParser Parser;
for (MemoryBufferRef MB : MBs) {
std::unique_ptr<object::Binary> Bin = check(object::createBinary(MB));
object::WindowsResource *RF = dyn_cast<object::WindowsResource>(Bin.get());
if (!RF)
fatal("cannot compile non-resource file as resource");
if (auto EC = Parser.parse(RF))
fatal("failed to parse .res file: " + toString(std::move(EC)));
}
Expected<std::unique_ptr<MemoryBuffer>> E =
llvm::object::writeWindowsResourceCOFF(Config->Machine, Parser);
if (!E)
fatal("failed to write .res to COFF: " + toString(E.takeError()));
MemoryBufferRef MBRef = **E;
make<std::unique_ptr<MemoryBuffer>>(std::move(*E)); // take ownership
return MBRef;
}
// Run MSVC link.exe for given in-memory object files.
// Command line options are copied from those given to LLD.
// This is for the /msvclto option.
void runMSVCLinker(std::string Rsp, ArrayRef<StringRef> Objects) {
// Write the in-memory object files to disk.
std::vector<TemporaryFile> Temps;
for (StringRef S : Objects) {
Temps.emplace_back("lto", "obj", S);
Rsp += quote(Temps.back().Path) + "\n";
}
log("link.exe " + Rsp);
// Run MSVC link.exe.
Temps.emplace_back("lto", "rsp", Rsp);
Executor E("link.exe");
E.add(Twine("@" + Temps.back().Path));
E.run();
}
// Create OptTable
// Create prefix string literals used in Options.td
#define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
#include "Options.inc"
#undef PREFIX
// Create table mapping all options defined in Options.td
static const llvm::opt::OptTable::Info InfoTable[] = {
#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12) \
{X1, X2, X10, X11, OPT_##ID, llvm::opt::Option::KIND##Class, \
X9, X8, OPT_##GROUP, OPT_##ALIAS, X7, X12},
#include "Options.inc"
#undef OPTION
};
COFFOptTable::COFFOptTable() : OptTable(InfoTable, true) {}
static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
StringRef S = Arg->getValue();
if (S != "windows" && S != "posix")
error("invalid response file quoting: " + S);
if (S == "windows")
return cl::TokenizeWindowsCommandLine;
return cl::TokenizeGNUCommandLine;
}
// The COFF linker always defaults to Windows quoting.
return cl::TokenizeWindowsCommandLine;
}
// Parses a given list of options.
opt::InputArgList ArgParser::parse(ArrayRef<const char *> Argv) {
// Make InputArgList from string vectors.
unsigned MissingIndex;
unsigned MissingCount;
SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
// We need to get the quoting style for response files before parsing all
// options so we parse here before and ignore all the options but
// --rsp-quoting.
opt::InputArgList Args = Table.ParseArgs(Vec, MissingIndex, MissingCount);
// Expand response files (arguments in the form of @<filename>)
// and then parse the argument again.
cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
Args = Table.ParseArgs(Vec, MissingIndex, MissingCount);
// Print the real command line if response files are expanded.
if (Args.hasArg(OPT_verbose) && Argv.size() != Vec.size()) {
std::string Msg = "Command line:";
for (const char *S : Vec)
Msg += " " + std::string(S);
message(Msg);
}
// Handle /WX early since it converts missing argument warnings to errors.
errorHandler().FatalWarnings = Args.hasFlag(OPT_WX, OPT_WX_no, false);
if (MissingCount)
fatal(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
for (auto *Arg : Args.filtered(OPT_UNKNOWN))
warn("ignoring unknown argument: " + Arg->getSpelling());
return Args;
}
// Tokenizes and parses a given string as command line in .drective section.
// /EXPORT options are processed in fastpath.
std::pair<opt::InputArgList, std::vector<StringRef>>
ArgParser::parseDirectives(StringRef S) {
std::vector<StringRef> Exports;
SmallVector<const char *, 16> Rest;
for (StringRef Tok : tokenize(S)) {
if (Tok.startswith_lower("/export:") || Tok.startswith_lower("-export:"))
Exports.push_back(Tok.substr(strlen("/export:")));
else
Rest.push_back(Tok.data());
}
// Make InputArgList from unparsed string vectors.
unsigned MissingIndex;
unsigned MissingCount;
opt::InputArgList Args = Table.ParseArgs(Rest, MissingIndex, MissingCount);
if (MissingCount)
fatal(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
for (auto *Arg : Args.filtered(OPT_UNKNOWN))
warn("ignoring unknown argument: " + Arg->getSpelling());
return {std::move(Args), std::move(Exports)};
}
// link.exe has an interesting feature. If LINK or _LINK_ environment
// variables exist, their contents are handled as command line strings.
// So you can pass extra arguments using them.
opt::InputArgList ArgParser::parseLINK(std::vector<const char *> Argv) {
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// Concatenate LINK env and command line arguments, and then parse them.
if (Optional<std::string> S = Process::GetEnv("LINK")) {
std::vector<const char *> V = tokenize(*S);
Argv.insert(Argv.begin(), V.begin(), V.end());
}
if (Optional<std::string> S = Process::GetEnv("_LINK_")) {
std::vector<const char *> V = tokenize(*S);
Argv.insert(Argv.begin(), V.begin(), V.end());
}
return parse(Argv);
}
std::vector<const char *> ArgParser::tokenize(StringRef S) {
SmallVector<const char *, 16> Tokens;
cl::TokenizeWindowsCommandLine(S, Saver, Tokens);
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return std::vector<const char *>(Tokens.begin(), Tokens.end());
}
void printHelp(const char *Argv0) {
COFFOptTable().PrintHelp(outs(), Argv0, "LLVM Linker", false);
}
} // namespace coff
} // namespace lld