[COFF] Improve correctness of def parsing for GNU features
The operator == used for exporting a function with a different
name in the DLL compared to the name in the import library
(which is useful for adding linker level aliases for function
in the import library) is a feature distinct and different from
the operator = used for exporting a function with a different
name (both in import library and DLL) than in the implementation
producing the DLL.
When creating an import library using dlltool, from a def file that
contains forwards (Func = OtherDll.Func), this shouldn't affect the
produced import library, which should still behave just as if it
was a normal exported function.
This clears a lot of confusion and subtle misunderstandings, and
avoids a parameter that was used to avoid creating weak aliases
when invoked from lld. (This parameter was added previously due to
the existing conflation of the two features.)
Differential Revision: https://reviews.llvm.org/D46245
llvm-svn: 331859
diff --git a/llvm/include/llvm/Object/COFFImportFile.h b/llvm/include/llvm/Object/COFFImportFile.h
index 7ca416f..0a4556a 100644
--- a/llvm/include/llvm/Object/COFFImportFile.h
+++ b/llvm/include/llvm/Object/COFFImportFile.h
@@ -74,6 +74,7 @@
std::string Name;
std::string ExtName;
std::string SymbolName;
+ std::string AliasTarget;
uint16_t Ordinal = 0;
bool Noname = false;
@@ -81,10 +82,6 @@
bool Private = false;
bool Constant = false;
- bool isWeak() {
- return ExtName.size() && ExtName != Name;
- }
-
friend bool operator==(const COFFShortExport &L, const COFFShortExport &R) {
return L.Name == R.Name && L.ExtName == R.ExtName &&
L.Ordinal == R.Ordinal && L.Noname == R.Noname &&
@@ -98,8 +95,7 @@
Error writeImportLibrary(StringRef ImportName, StringRef Path,
ArrayRef<COFFShortExport> Exports,
- COFF::MachineTypes Machine, bool MakeWeakAliases,
- bool MinGW);
+ COFF::MachineTypes Machine, bool MinGW);
} // namespace object
} // namespace llvm
diff --git a/llvm/lib/Object/COFFImportFile.cpp b/llvm/lib/Object/COFFImportFile.cpp
index c249a6d..4bde1db 100644
--- a/llvm/lib/Object/COFFImportFile.cpp
+++ b/llvm/lib/Object/COFFImportFile.cpp
@@ -566,8 +566,7 @@
Error writeImportLibrary(StringRef ImportName, StringRef Path,
ArrayRef<COFFShortExport> Exports,
- MachineTypes Machine, bool MakeWeakAliases,
- bool MinGW) {
+ MachineTypes Machine, bool MinGW) {
std::vector<NewArchiveMember> Members;
ObjectFactory OF(llvm::sys::path::filename(ImportName), Machine);
@@ -585,12 +584,6 @@
if (E.Private)
continue;
- if (E.isWeak() && MakeWeakAliases) {
- Members.push_back(OF.createWeakExternal(E.Name, E.ExtName, false));
- Members.push_back(OF.createWeakExternal(E.Name, E.ExtName, true));
- continue;
- }
-
ImportType ImportType = IMPORT_CODE;
if (E.Data)
ImportType = IMPORT_DATA;
@@ -606,6 +599,12 @@
if (!Name)
return Name.takeError();
+ if (!E.AliasTarget.empty() && *Name != E.AliasTarget) {
+ Members.push_back(OF.createWeakExternal(E.AliasTarget, *Name, false));
+ Members.push_back(OF.createWeakExternal(E.AliasTarget, *Name, true));
+ continue;
+ }
+
Members.push_back(
OF.createShortImport(*Name, E.Ordinal, ImportType, NameType));
}
diff --git a/llvm/lib/Object/COFFModuleDefinition.cpp b/llvm/lib/Object/COFFModuleDefinition.cpp
index a571354..c703071 100644
--- a/llvm/lib/Object/COFFModuleDefinition.cpp
+++ b/llvm/lib/Object/COFFModuleDefinition.cpp
@@ -37,6 +37,7 @@
Identifier,
Comma,
Equal,
+ EqualEqual,
KwBase,
KwConstant,
KwData,
@@ -104,9 +105,10 @@
}
case '=':
Buf = Buf.drop_front();
- // GNU dlltool accepts both = and ==.
- if (Buf.startswith("="))
+ if (Buf.startswith("=")) {
Buf = Buf.drop_front();
+ return Token(EqualEqual, "==");
+ }
return Token(Equal, "=");
case ',':
Buf = Buf.drop_front();
@@ -282,6 +284,13 @@
E.Private = true;
continue;
}
+ if (Tok.K == EqualEqual) {
+ read();
+ E.AliasTarget = Tok.Value;
+ if (Machine == IMAGE_FILE_MACHINE_I386 && !isDecorated(E.AliasTarget, MingwDef))
+ E.AliasTarget = std::string("_").append(E.AliasTarget);
+ continue;
+ }
unget();
Info.Exports.push_back(E);
return Error::success();
diff --git a/llvm/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp b/llvm/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp
index 684617e..f8de7ca 100644
--- a/llvm/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp
+++ b/llvm/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp
@@ -158,7 +158,7 @@
if (Machine == IMAGE_FILE_MACHINE_I386 && Args.getLastArg(OPT_k)) {
for (COFFShortExport& E : Def->Exports) {
- if (E.isWeak() || (!E.Name.empty() && E.Name[0] == '?'))
+ if (!E.AliasTarget.empty() || (!E.Name.empty() && E.Name[0] == '?'))
continue;
E.SymbolName = E.Name;
// Trim off the trailing decoration. Symbols will always have a
@@ -173,7 +173,7 @@
}
}
- if (writeImportLibrary(Def->OutputFile, Path, Def->Exports, Machine, true, true))
+ if (writeImportLibrary(Def->OutputFile, Path, Def->Exports, Machine, true))
return 1;
return 0;
}
diff --git a/llvm/test/tools/llvm-dlltool/coff-decorated.def b/llvm/test/tools/llvm-dlltool/coff-decorated.def
index 5a908f3..d6496b0 100644
--- a/llvm/test/tools/llvm-dlltool/coff-decorated.def
+++ b/llvm/test/tools/llvm-dlltool/coff-decorated.def
@@ -7,7 +7,7 @@
CdeclFunction
StdcallFunction@4
@FastcallFunction@4
-StdcallAlias@4=StdcallFunction@4
+StdcallAlias@4==StdcallFunction@4
??_7exception@@6B@
; CHECK: Name type: noprefix
diff --git a/llvm/test/tools/llvm-dlltool/coff-weak-exports.def b/llvm/test/tools/llvm-dlltool/coff-weak-exports.def
index b4709e9..693a03a 100644
--- a/llvm/test/tools/llvm-dlltool/coff-weak-exports.def
+++ b/llvm/test/tools/llvm-dlltool/coff-weak-exports.def
@@ -4,8 +4,25 @@
LIBRARY test.dll
EXPORTS
TestFunction==AltTestFunction
+; When creating an import library, the DLL internal function name of
+; the implementation of a function isn't visible at all.
+ImpLibName = Implementation
+; A different import library name and implementation name can be mixed
+; with exposing it via a different name in the DLL than in code.
+ImpLibName2 = Implementation2 == AltTestFunction2
+; The fact that a DLL export entry is a forward to a different DLL doesn't
+; matter for the import library
+ImpLibName3 = kernel32.Sleep
; CHECK: U AltTestFunction
; CHECK-NEXT: w TestFunction
; CHECK: U __imp_AltTestFunction
; CHECK-NEXT: w __imp_TestFunction
+; CHECK: T ImpLibName
+; CHECK-NEXT: T __imp_ImpLibName
+; CHECK: U AltTestFunction2
+; CHECK-NEXT: w ImpLibName2
+; CHECK: U __imp_AltTestFunction2
+; CHECK-NEXT: w __imp_ImpLibName2
+; CHECK: T ImpLibName3
+; CHECK-NEXT: T __imp_ImpLibName3