[lld] r241213 - COFF: Simplify and rename findMangle. NFC.
Rui Ueyama
ruiu at google.com
Wed Jul 1 17:04:14 PDT 2015
Author: ruiu
Date: Wed Jul 1 19:04:14 2015
New Revision: 241213
URL: http://llvm.org/viewvc/llvm-project?rev=241213&view=rev
Log:
COFF: Simplify and rename findMangle. NFC.
Occasionally we have to resolve an undefined symbol to its
mangled symbol. Previously, we did that on calling side of
findMangle by explicitly updating SymbolBody.
In this patch, mangled symbols are handled as weak aliases
for undefined symbols.
Modified:
lld/trunk/COFF/Config.h
lld/trunk/COFF/DLL.cpp
lld/trunk/COFF/Driver.cpp
lld/trunk/COFF/Driver.h
lld/trunk/COFF/SymbolTable.cpp
lld/trunk/COFF/SymbolTable.h
lld/trunk/COFF/Writer.cpp
Modified: lld/trunk/COFF/Config.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Config.h?rev=241213&r1=241212&r2=241213&view=diff
==============================================================================
--- lld/trunk/COFF/Config.h (original)
+++ lld/trunk/COFF/Config.h Wed Jul 1 19:04:14 2015
@@ -22,13 +22,13 @@ namespace coff {
using llvm::COFF::WindowsSubsystem;
using llvm::StringRef;
-struct Symbol;
+class Undefined;
// Represents an /export option.
struct Export {
StringRef Name;
StringRef ExtName;
- Symbol *Sym = nullptr;
+ Undefined *Sym = nullptr;
uint16_t Ordinal = 0;
bool Noname = false;
bool Data = false;
@@ -42,7 +42,7 @@ struct Configuration {
llvm::COFF::MachineTypes MachineType = llvm::COFF::IMAGE_FILE_MACHINE_AMD64;
bool Verbose = false;
WindowsSubsystem Subsystem = llvm::COFF::IMAGE_SUBSYSTEM_UNKNOWN;
- StringRef EntryName;
+ Undefined *Entry = nullptr;
bool NoEntry = false;
std::string OutputFile;
bool DoGC = true;
Modified: lld/trunk/COFF/DLL.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/DLL.cpp?rev=241213&r1=241212&r2=241213&view=diff
==============================================================================
--- lld/trunk/COFF/DLL.cpp (original)
+++ lld/trunk/COFF/DLL.cpp Wed Jul 1 19:04:14 2015
@@ -420,7 +420,7 @@ public:
void writeTo(uint8_t *Buf) override {
for (Export &E : Config->Exports) {
- auto *D = cast<Defined>(E.Sym->Body);
+ auto *D = cast<Defined>(E.Sym->getReplacement());
write32le(Buf + FileOff + E.Ordinal * 4, D->getRVA());
}
}
Modified: lld/trunk/COFF/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Driver.cpp?rev=241213&r1=241212&r2=241213&view=diff
==============================================================================
--- lld/trunk/COFF/Driver.cpp (original)
+++ lld/trunk/COFF/Driver.cpp Wed Jul 1 19:04:14 2015
@@ -202,9 +202,10 @@ void LinkerDriver::addLibSearchPaths() {
}
}
-void LinkerDriver::addUndefined(StringRef Sym) {
- Symtab.addUndefined(Sym);
- Config->GCRoots.insert(Sym);
+Undefined *LinkerDriver::addUndefined(StringRef Name) {
+ Undefined *U = Symtab.addUndefined(Name);
+ Config->GCRoots.insert(Name);
+ return U;
}
// Windows specific -- find default entry point name.
@@ -286,10 +287,8 @@ bool LinkerDriver::link(llvm::ArrayRef<c
Config->Force = true;
// Handle /entry
- if (auto *Arg = Args.getLastArg(OPT_entry)) {
- Config->EntryName = Arg->getValue();
- addUndefined(Config->EntryName);
- }
+ if (auto *Arg = Args.getLastArg(OPT_entry))
+ Config->Entry = addUndefined(Arg->getValue());
// Handle /noentry
if (Args.hasArg(OPT_noentry)) {
@@ -304,10 +303,8 @@ bool LinkerDriver::link(llvm::ArrayRef<c
if (Args.hasArg(OPT_dll)) {
Config->DLL = true;
Config->ManifestID = 2;
- if (Config->EntryName.empty() && !Config->NoEntry) {
- Config->EntryName = "_DllMainCRTStartup";
- addUndefined("_DllMainCRTStartup");
- }
+ if (Config->Entry == nullptr && !Config->NoEntry)
+ Config->Entry = addUndefined("_DllMainCRTStartup");
}
// Handle /fixed
@@ -544,14 +541,13 @@ bool LinkerDriver::link(llvm::ArrayRef<c
// Windows specific -- If entry point name is not given, we need to
// infer that from user-defined entry name.
- if (Config->EntryName.empty() && !Config->NoEntry) {
+ if (Config->Entry == nullptr && !Config->NoEntry) {
StringRef S = findDefaultEntry();
if (S.empty()) {
llvm::errs() << "entry point must be defined\n";
return false;
}
- Config->EntryName = S;
- addUndefined(S);
+ Config->Entry = addUndefined(S);
}
// Resolve auxiliary symbols until converge.
@@ -561,9 +557,16 @@ bool LinkerDriver::link(llvm::ArrayRef<c
for (;;) {
size_t Ver = Symtab.getVersion();
+ // Windows specific -- if entry point is not found,
+ // search for its mangled names.
+ if (Config->Entry)
+ Symtab.mangleMaybe(Config->Entry);
+
// Windows specific -- Make sure we resolve all dllexported symbols.
- for (Export &E : Config->Exports)
- addUndefined(E.Name);
+ for (Export &E : Config->Exports) {
+ E.Sym = addUndefined(E.Name);
+ Symtab.mangleMaybe(E.Sym);
+ }
// Add weak aliases. Weak aliases is a mechanism to give remaining
// undefined symbols final chance to be resolved successfully.
@@ -585,30 +588,6 @@ bool LinkerDriver::link(llvm::ArrayRef<c
break;
}
- // Windows specific -- if entry point is not found,
- // search for its mangled names.
- if (!Config->EntryName.empty() && !Symtab.find(Config->EntryName)) {
- StringRef Name;
- Symbol *Sym;
- std::tie(Name, Sym) = Symtab.findMangled(Config->EntryName);
- if (Sym)
- Symtab.rename(Config->EntryName, Name);
- }
-
- // Windows specific -- resolve dllexported symbols.
- for (Export &E : Config->Exports) {
- StringRef Name;
- Symbol *Sym;
- std::tie(Name, Sym) = Symtab.findMangled(E.Name);
- if (!Sym) {
- llvm::errs() << "exported symbol is not defined: " << E.Name << "\n";
- return false;
- }
- if (E.Name != Name)
- Symtab.rename(E.Name, Name);
- E.Sym = Sym;
- }
-
// Make sure we have resolved all symbols.
if (Symtab.reportRemainingUndefines())
return false;
Modified: lld/trunk/COFF/Driver.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Driver.h?rev=241213&r1=241212&r2=241213&view=diff
==============================================================================
--- lld/trunk/COFF/Driver.h (original)
+++ lld/trunk/COFF/Driver.h Wed Jul 1 19:04:14 2015
@@ -92,7 +92,7 @@ private:
std::vector<StringRef> SearchPaths;
std::set<std::string> VisitedFiles;
- void addUndefined(StringRef Sym);
+ Undefined *addUndefined(StringRef Sym);
// Windows specific -- "main" is not the only main function in Windows.
// You can choose one from these four -- {w,}{WinMain,main}.
Modified: lld/trunk/COFF/SymbolTable.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/SymbolTable.cpp?rev=241213&r1=241212&r2=241213&view=diff
==============================================================================
--- lld/trunk/COFF/SymbolTable.cpp (original)
+++ lld/trunk/COFF/SymbolTable.cpp Wed Jul 1 19:04:14 2015
@@ -25,8 +25,6 @@ namespace coff {
SymbolTable::SymbolTable() {
addSymbol(new (Alloc) DefinedAbsolute("__ImageBase", Config->ImageBase));
- if (!Config->EntryName.empty())
- addSymbol(new (Alloc) Undefined(Config->EntryName));
}
void SymbolTable::addFile(std::unique_ptr<InputFile> FileP) {
@@ -123,9 +121,11 @@ bool SymbolTable::reportRemainingUndefin
continue;
StringRef Name = Undef->getName();
// The weak alias may have been resovled, so check for that.
- if (auto *D = dyn_cast_or_null<Defined>(Undef->WeakAlias)) {
- Sym->Body = D;
- continue;
+ if (SymbolBody *Alias = Undef->WeakAlias) {
+ if (auto *D = dyn_cast<Defined>(Alias->getReplacement())) {
+ Sym->Body = D;
+ continue;
+ }
}
// If we can resolve a symbol by removing __imp_ prefix, do that.
// This odd rule is for compatibility with MSVC linker.
@@ -245,34 +245,30 @@ Symbol *SymbolTable::findSymbol(StringRe
return It->second;
}
-// Find a given symbol or its mangled symbol.
-std::pair<StringRef, Symbol *> SymbolTable::findMangled(StringRef S) {
- auto It = Symtab.find(S);
- if (It != Symtab.end()) {
- Symbol *Sym = It->second;
- if (isa<Defined>(Sym->Body))
- return std::make_pair(S, Sym);
- }
+void SymbolTable::mangleMaybe(Undefined *U) {
+ if (U->WeakAlias)
+ return;
+ if (!isa<Undefined>(U->getReplacement()))
+ return;
// In Microsoft ABI, a non-member function name is mangled this way.
- std::string Prefix = ("?" + S + "@@Y").str();
+ std::string Prefix = ("?" + U->getName() + "@@Y").str();
for (auto I : Symtab) {
StringRef Name = I.first;
- Symbol *Sym = I.second;
+ Symbol *New = I.second;
if (!Name.startswith(Prefix))
continue;
- if (auto *B = dyn_cast<Lazy>(Sym->Body)) {
- addMemberFile(B);
- run();
- }
- if (isa<Defined>(Sym->Body))
- return std::make_pair(Name, Sym);
+ U->WeakAlias = New->Body;
+ if (auto *L = dyn_cast<Lazy>(New->Body))
+ addMemberFile(L);
+ return;
}
- return std::make_pair(S, nullptr);
}
-std::error_code SymbolTable::addUndefined(StringRef Name) {
- return addSymbol(new (Alloc) Undefined(Name));
+Undefined *SymbolTable::addUndefined(StringRef Name) {
+ auto *U = new (Alloc) Undefined(Name);
+ addSymbol(U);
+ return U;
}
// Resolve To, and make From an alias to To.
Modified: lld/trunk/COFF/SymbolTable.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/SymbolTable.h?rev=241213&r1=241212&r2=241213&view=diff
==============================================================================
--- lld/trunk/COFF/SymbolTable.h (original)
+++ lld/trunk/COFF/SymbolTable.h Wed Jul 1 19:04:14 2015
@@ -61,10 +61,11 @@ public:
Defined *find(StringRef Name);
Symbol *findSymbol(StringRef Name);
- // Find a symbol assuming that Name is a function name.
- // Not only a given string but its mangled names (in MSVC C++ manner)
- // will be searched.
- std::pair<StringRef, Symbol *> findMangled(StringRef Name);
+ // Occasionally we have to resolve an undefined symbol to its
+ // mangled symbol. This function tries to find a mangled name
+ // for U from the symbol table, and if found, set the symbol as
+ // a weak alias for U.
+ void mangleMaybe(Undefined *U);
// Print a layout map to OS.
void printMap(llvm::raw_ostream &OS);
@@ -82,7 +83,7 @@ public:
std::vector<ObjectFile *> ObjectFiles;
// Creates an Undefined symbol for a given name.
- std::error_code addUndefined(StringRef Name);
+ Undefined *addUndefined(StringRef Name);
// Rename From -> To in the symbol table.
std::error_code rename(StringRef From, StringRef To);
Modified: lld/trunk/COFF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Writer.cpp?rev=241213&r1=241212&r2=241213&view=diff
==============================================================================
--- lld/trunk/COFF/Writer.cpp (original)
+++ lld/trunk/COFF/Writer.cpp Wed Jul 1 19:04:14 2015
@@ -348,7 +348,7 @@ void Writer::writeHeader() {
PE->SizeOfImage = SizeOfImage;
PE->SizeOfHeaders = SizeOfHeaders;
if (!Config->NoEntry) {
- Defined *Entry = cast<Defined>(Symtab->find(Config->EntryName));
+ Defined *Entry = cast<Defined>(Config->Entry->getReplacement());
PE->AddressOfEntryPoint = Entry->getRVA();
}
PE->SizeOfStackReserve = Config->StackReserve;
More information about the llvm-commits
mailing list