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[llvm-dlltool] Handle import renaming using other name types, when possible #98228

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Merged
merged 1 commit into from
Jul 16, 2024
Merged

[llvm-dlltool] Handle import renaming using other name types, when possible #98228

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66 changes: 45 additions & 21 deletions llvm/lib/Object/COFFImportFile.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -52,25 +52,37 @@ StringRef COFFImportFile::getFileFormatName() const {
}
}

StringRef COFFImportFile::getExportName() const {
const coff_import_header *hdr = getCOFFImportHeader();
StringRef name = Data.getBuffer().substr(sizeof(*hdr)).split('\0').first;

static StringRef applyNameType(ImportNameType Type, StringRef name) {
auto ltrim1 = [](StringRef s, StringRef chars) {
return !s.empty() && chars.contains(s[0]) ? s.substr(1) : s;
};

switch (hdr->getNameType()) {
case IMPORT_ORDINAL:
name = "";
break;
switch (Type) {
case IMPORT_NAME_NOPREFIX:
name = ltrim1(name, "?@_");
break;
case IMPORT_NAME_UNDECORATE:
name = ltrim1(name, "?@_");
name = name.substr(0, name.find('@'));
break;
default:
break;
}
return name;
}

StringRef COFFImportFile::getExportName() const {
const coff_import_header *hdr = getCOFFImportHeader();
StringRef name = Data.getBuffer().substr(sizeof(*hdr)).split('\0').first;

switch (hdr->getNameType()) {
case IMPORT_ORDINAL:
name = "";
break;
case IMPORT_NAME_NOPREFIX:
case IMPORT_NAME_UNDECORATE:
name = applyNameType(static_cast<ImportNameType>(hdr->getNameType()), name);
break;
case IMPORT_NAME_EXPORTAS: {
// Skip DLL name
name = Data.getBuffer().substr(sizeof(*hdr) + name.size() + 1);
Expand Down Expand Up @@ -691,26 +703,38 @@ Error writeImportLibrary(StringRef ImportName, StringRef Path,
Name.swap(*ReplacedName);
}

if (!E.ImportName.empty() && Name != E.ImportName) {
StringRef Prefix = "";
if (Machine == IMAGE_FILE_MACHINE_I386 && AddUnderscores)
Prefix = "_";

if (ImportType == IMPORT_CODE)
Members.push_back(OF.createWeakExternal((Prefix + E.ImportName).str(),
Name, false, M));
Members.push_back(OF.createWeakExternal((Prefix + E.ImportName).str(),
Name, true, M));
continue;
}

ImportNameType NameType;
std::string ExportName;
if (E.Noname) {
NameType = IMPORT_ORDINAL;
} else if (!E.ExportAs.empty()) {
NameType = IMPORT_NAME_EXPORTAS;
ExportName = E.ExportAs;
} else if (!E.ImportName.empty()) {
// If we need to import from a specific ImportName, we may need to use
// a weak alias (which needs another import to point at). But if we can
// express ImportName based on the symbol name and a specific NameType,
// prefer that over an alias.
if (Machine == IMAGE_FILE_MACHINE_I386 &&
applyNameType(IMPORT_NAME_UNDECORATE, Name) == E.ImportName)
NameType = IMPORT_NAME_UNDECORATE;
else if (Machine == IMAGE_FILE_MACHINE_I386 &&
applyNameType(IMPORT_NAME_NOPREFIX, Name) == E.ImportName)
NameType = IMPORT_NAME_NOPREFIX;
else if (Name == E.ImportName)
NameType = IMPORT_NAME;
else {
StringRef Prefix = "";
if (Machine == IMAGE_FILE_MACHINE_I386 && AddUnderscores)
Prefix = "_";

if (ImportType == IMPORT_CODE)
Members.push_back(OF.createWeakExternal(
(Prefix + E.ImportName).str(), Name, false, M));
Members.push_back(OF.createWeakExternal((Prefix + E.ImportName).str(),
Name, true, M));
continue;
}
} else {
NameType = getNameType(SymbolName, E.Name, M, MinGW);
}
Expand Down
16 changes: 16 additions & 0 deletions llvm/test/tools/llvm-dlltool/coff-decorated.def
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,10 @@ StdcallExportName@4=StdcallInternalFunction@4
OtherStdcallExportName@4=CdeclInternalFunction
CdeclExportName=StdcallInternalFunction@4

NoprefixStdcall@4 == NoprefixStdcall@4
DecoratedStdcall@4 == _DecoratedStdcall@4
UndecoratedStdcall@4 == UndecoratedStdcall

; CHECK: Name type: noprefix
; CHECK-NEXT: Export name: CdeclFunction
; CHECK-NEXT: Symbol: __imp__CdeclFunction
Expand Down Expand Up @@ -43,3 +47,15 @@ CdeclExportName=StdcallInternalFunction@4
; CHECK-NEXT: Export name: CdeclExportName
; CHECK-NEXT: Symbol: __imp__CdeclExportName
; CHECK-NEXT: Symbol: _CdeclExportName
; CHECK: Name type: noprefix
; CHECK-NEXT: Export name: NoprefixStdcall@4
; CHECK-NEXT: Symbol: __imp__NoprefixStdcall@4
; CHECK-NEXT: Symbol: _NoprefixStdcall@4
; CHECK: Name type: name
; CHECK-NEXT: Export name: _DecoratedStdcall@4
; CHECK-NEXT: Symbol: __imp__DecoratedStdcall@4
; CHECK-NEXT: Symbol: _DecoratedStdcall@4
; CHECK: Name type: undecorate
; CHECK-NEXT: Export name: UndecoratedStdcall
; CHECK-NEXT: Symbol: __imp__UndecoratedStdcall@4
; CHECK-NEXT: Symbol: _UndecoratedStdcall@4
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