[llvm-branch-commits] [lld] [llvm] Backport fixes for ARM64EC import libraries (PR #84590)

Daniel Paoliello via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Wed Mar 13 09:13:49 PDT 2024


https://github.com/dpaoliello updated https://github.com/llvm/llvm-project/pull/84590

>From e96d29f7e80a89204ba541a8af516bf47698d93f Mon Sep 17 00:00:00 2001
From: Jacek Caban <jacek at codeweavers.com>
Date: Tue, 6 Feb 2024 13:47:58 +0100
Subject: [PATCH 1/4] [llvm-readobj][Object][COFF] Print COFF import library
 symbol export name. (#78769)

getExportName implementation is based on lld-link. In its current form,
it's mostly about convenience, but it will be more useful for EXPORTAS
support, for which export name is not possible to deduce from other
printed properties.
---
 lld/test/COFF/def-export-cpp.s                |  1 +
 lld/test/COFF/def-export-stdcall.s            | 13 ++++++++++
 lld/test/COFF/dllexport.s                     |  4 +++
 llvm/include/llvm/Object/COFFImportFile.h     |  1 +
 llvm/lib/Object/COFFImportFile.cpp            | 26 +++++++++++++++++++
 .../tools/llvm-dlltool/coff-decorated.def     |  7 +++++
 llvm/test/tools/llvm-dlltool/coff-exports.def |  3 +++
 llvm/test/tools/llvm-dlltool/coff-noname.def  |  1 +
 .../llvm-dlltool/no-leading-underscore.def    |  2 ++
 llvm/test/tools/llvm-lib/arm64ec-implib.test  |  2 ++
 .../tools/llvm-readobj/COFF/file-headers.test |  1 +
 llvm/tools/llvm-readobj/COFFImportDumper.cpp  |  3 +++
 12 files changed, 64 insertions(+)

diff --git a/lld/test/COFF/def-export-cpp.s b/lld/test/COFF/def-export-cpp.s
index e00b35b1c5b39b..370b8ddba4104b 100644
--- a/lld/test/COFF/def-export-cpp.s
+++ b/lld/test/COFF/def-export-cpp.s
@@ -10,6 +10,7 @@
 
 # IMPLIB: File: foo.dll
 # IMPLIB: Name type: undecorate
+# IMPLIB-NEXT: Export name: GetPathOnDisk
 # IMPLIB-NEXT: Symbol: __imp_?GetPathOnDisk@@YA_NPEA_W at Z
 # IMPLIB-NEXT: Symbol: ?GetPathOnDisk@@YA_NPEA_W at Z
 
diff --git a/lld/test/COFF/def-export-stdcall.s b/lld/test/COFF/def-export-stdcall.s
index f015e205c74a33..7e4e04c77cbe7a 100644
--- a/lld/test/COFF/def-export-stdcall.s
+++ b/lld/test/COFF/def-export-stdcall.s
@@ -6,15 +6,19 @@
 # RUN: llvm-readobj --coff-exports %t.dll | FileCheck -check-prefix UNDECORATED-EXPORTS %s
 
 # UNDECORATED-IMPLIB: Name type: noprefix
+# UNDECORATED-IMPLIB-NEXT: Export name: _underscored
 # UNDECORATED-IMPLIB-NEXT: __imp___underscored
 # UNDECORATED-IMPLIB-NEXT: __underscored
 # UNDECORATED-IMPLIB: Name type: undecorate
+# UNDECORATED-IMPLIB-NEXT: Export name: fastcall
 # UNDECORATED-IMPLIB-NEXT: __imp_ at fastcall@8
 # UNDECORATED-IMPLIB-NEXT: fastcall at 8
 # UNDECORATED-IMPLIB: Name type: undecorate
+# UNDECORATED-IMPLIB-NEXT: Export name: stdcall
 # UNDECORATED-IMPLIB-NEXT: __imp__stdcall at 8
 # UNDECORATED-IMPLIB-NEXT: _stdcall at 8
 # UNDECORATED-IMPLIB: Name type: undecorate
+# UNDECORATED-IMPLIB-NEXT: Export name: vectorcall
 # UNDECORATED-IMPLIB-NEXT: __imp_vectorcall@@8
 # UNDECORATED-IMPLIB-NEXT: vectorcall@@8
 
@@ -30,12 +34,15 @@
 # RUN: llvm-readobj --coff-exports %t.dll | FileCheck -check-prefix DECORATED-EXPORTS %s
 
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: @fastcall at 8
 # DECORATED-IMPLIB-NEXT: __imp_ at fastcall@8
 # DECORATED-IMPLIB-NEXT: @fastcall at 8
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: _stdcall at 8
 # DECORATED-IMPLIB-NEXT: __imp__stdcall at 8
 # DECORATED-IMPLIB-NEXT: _stdcall at 8
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: vectorcall@@8
 # DECORATED-IMPLIB-NEXT: __imp_vectorcall@@8
 # DECORATED-IMPLIB-NEXT: vectorcall@@8
 
@@ -51,14 +58,17 @@
 # RUN: llvm-readobj --coff-exports %t.dll | FileCheck -check-prefix DECORATED-MINGW-EXPORTS %s
 
 # DECORATED-MINGW-IMPLIB: Name type: name
+# DECORATED-MINGW-IMPLIB-NEXT: Export name: @fastcall at 8
 # DECORATED-MINGW-IMPLIB-NEXT: __imp_ at fastcall@8
 # DECORATED-MINGW-IMPLIB-NEXT: fastcall at 8
 # DECORATED-MINGW-IMPLIB: Name type: noprefix
+# DECORATED-MINGW-IMPLIB-NEXT: Export name: stdcall at 8
 # DECORATED-MINGW-IMPLIB-NEXT: __imp__stdcall at 8
 # DECORATED-MINGW-IMPLIB-NEXT: _stdcall at 8
 # GNU tools don't support vectorcall, but this test is just to track that
 # lld's behaviour remains consistent over time.
 # DECORATED-MINGW-IMPLIB: Name type: name
+# DECORATED-MINGW-IMPLIB-NEXT: Export name: vectorcall@@8
 # DECORATED-MINGW-IMPLIB-NEXT: __imp_vectorcall@@8
 # DECORATED-MINGW-IMPLIB-NEXT: vectorcall@@8
 
@@ -75,14 +85,17 @@
 # RUN: llvm-readobj --coff-exports %t.dll | FileCheck -check-prefix MINGW-KILL-AT-EXPORTS %s
 
 # MINGW-KILL-AT-IMPLIB: Name type: noprefix
+# MINGW-KILL-AT-IMPLIB: Export name: fastcall
 # MINGW-KILL-AT-IMPLIB: __imp__fastcall
 # MINGW-KILL-AT-IMPLIB-NEXT: _fastcall
 # MINGW-KILL-AT-IMPLIB: Name type: noprefix
+# MINGW-KILL-AT-IMPLIB-NEXT: Export name: stdcall
 # MINGW-KILL-AT-IMPLIB-NEXT: __imp__stdcall
 # MINGW-KILL-AT-IMPLIB-NEXT: _stdcall
 # GNU tools don't support vectorcall, but this test is just to track that
 # lld's behaviour remains consistent over time.
 # MINGW-KILL-AT-IMPLIB: Name type: noprefix
+# MINGW-KILL-AT-IMPLIB-NEXT: Export name: vectorcall
 # MINGW-KILL-AT-IMPLIB-NEXT: __imp__vectorcall
 # MINGW-KILL-AT-IMPLIB-NEXT: _vectorcall
 
diff --git a/lld/test/COFF/dllexport.s b/lld/test/COFF/dllexport.s
index a238b70ce1b4f6..b04ebc3a33c3e2 100644
--- a/lld/test/COFF/dllexport.s
+++ b/lld/test/COFF/dllexport.s
@@ -6,15 +6,19 @@
 # RUN: llvm-readobj --coff-exports %t.dll | FileCheck -check-prefix DECORATED-EXPORTS %s
 
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: @fastcall at 8
 # DECORATED-IMPLIB-NEXT: __imp_ at fastcall@8
 # DECORATED-IMPLIB-NEXT: @fastcall at 8
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: _stdcall at 8
 # DECORATED-IMPLIB-NEXT: __imp__stdcall at 8
 # DECORATED-IMPLIB-NEXT: _stdcall at 8
 # DECORATED-IMPLIB: Name type: noprefix
+# DECORATED-IMPLIB-NEXT: Export name: _underscored
 # DECORATED-IMPLIB-NEXT: __imp___underscored
 # DECORATED-IMPLIB-NEXT: __underscored
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: vectorcall@@8
 # DECORATED-IMPLIB-NEXT: __imp_vectorcall@@8
 # DECORATED-IMPLIB-NEXT: vectorcall@@8
 
diff --git a/llvm/include/llvm/Object/COFFImportFile.h b/llvm/include/llvm/Object/COFFImportFile.h
index edc836ff0348cb..45a4a795fd1903 100644
--- a/llvm/include/llvm/Object/COFFImportFile.h
+++ b/llvm/include/llvm/Object/COFFImportFile.h
@@ -66,6 +66,7 @@ class COFFImportFile : public SymbolicFile {
   uint16_t getMachine() const { return getCOFFImportHeader()->Machine; }
 
   StringRef getFileFormatName() const;
+  StringRef getExportName() const;
 
 private:
   bool isData() const {
diff --git a/llvm/lib/Object/COFFImportFile.cpp b/llvm/lib/Object/COFFImportFile.cpp
index 60556c149bf735..d7d26f4f4180c3 100644
--- a/llvm/lib/Object/COFFImportFile.cpp
+++ b/llvm/lib/Object/COFFImportFile.cpp
@@ -52,6 +52,32 @@ StringRef COFFImportFile::getFileFormatName() const {
   }
 }
 
+StringRef COFFImportFile::getExportName() const {
+  const coff_import_header *hdr = getCOFFImportHeader();
+  StringRef name = Data.getBuffer().substr(sizeof(*hdr)).split('\0').first;
+
+  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;
+  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;
+}
+
 static uint16_t getImgRelRelocation(MachineTypes Machine) {
   switch (Machine) {
   default:
diff --git a/llvm/test/tools/llvm-dlltool/coff-decorated.def b/llvm/test/tools/llvm-dlltool/coff-decorated.def
index 856804686168b1..fc81f23d09d6c4 100644
--- a/llvm/test/tools/llvm-dlltool/coff-decorated.def
+++ b/llvm/test/tools/llvm-dlltool/coff-decorated.def
@@ -14,25 +14,32 @@ OtherStdcallExportName at 4=CdeclInternalFunction
 CdeclExportName=StdcallInternalFunction at 4
 
 ; CHECK:      Name type: noprefix
+; CHECK-NEXT: Export name: CdeclFunction
 ; CHECK-NEXT: Symbol: __imp__CdeclFunction
 ; CHECK-NEXT: Symbol: _CdeclFunction
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: StdcallFunction
 ; CHECK-NEXT: Symbol: __imp__StdcallFunction at 4
 ; CHECK-NEXT: Symbol: _StdcallFunction at 4
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: FastcallFunction
 ; CHECK-NEXT: Symbol: __imp_ at FastcallFunction@4
 ; CHECK-NEXT: Symbol: @FastcallFunction at 4
 ; CHECK:      Name type: name
+; CHECK-NEXT: Export name: ??_7exception@@6B@
 ; CHECK-NEXT: Symbol: __imp_??_7exception@@6B@
 ; CHECK-NEXT: Symbol: ??_7exception@@6B@
 ; CHECK-NM: W _StdcallAlias at 4
 ; CHECK-NM: U _StdcallFunction at 4
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: StdcallExportName
 ; CHECK-NEXT: Symbol: __imp__StdcallExportName at 4{{$}}
 ; CHECK-NEXT: Symbol: _StdcallExportName at 4{{$}}
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: OtherStdcallExportName
 ; CHECK-NEXT: Symbol: __imp__OtherStdcallExportName at 4{{$}}
 ; CHECK-NEXT: Symbol: _OtherStdcallExportName at 4{{$}}
 ; CHECK:      Name type: noprefix
+; CHECK-NEXT: Export name: CdeclExportName
 ; CHECK-NEXT: Symbol: __imp__CdeclExportName
 ; CHECK-NEXT: Symbol: _CdeclExportName
diff --git a/llvm/test/tools/llvm-dlltool/coff-exports.def b/llvm/test/tools/llvm-dlltool/coff-exports.def
index 57c55744602156..267424db1b8c1d 100644
--- a/llvm/test/tools/llvm-dlltool/coff-exports.def
+++ b/llvm/test/tools/llvm-dlltool/coff-exports.def
@@ -17,12 +17,15 @@ AnotherFunction
 ; CHECK-ARM64: Format: COFF-import-file-ARM64
 ; CHECK: Type: code
 ; CHECK:      Name type: name
+; CHECK-NEXT: Export name: TestFunction1
 ; CHECK-NEXT: Symbol: __imp_TestFunction1
 ; CHECK-NEXT: Symbol: TestFunction1
 ; CHECK:      Name type: name
+; CHECK-NEXT: Export name: TestFunction2
 ; CHECK-NEXT: Symbol: __imp_TestFunction2{{$}}
 ; CHECK-NEXT: Symbol: TestFunction2{{$}}
 ; CHECK:      Name type: name
+; CHECK-NEXT: Export name: TestFunction3
 ; CHECK-NEXT: Symbol: __imp_TestFunction3{{$}}
 ; CHECK-NEXT: Symbol: TestFunction3{{$}}
 
diff --git a/llvm/test/tools/llvm-dlltool/coff-noname.def b/llvm/test/tools/llvm-dlltool/coff-noname.def
index 27e60efbd2d802..7cb05846ce28a2 100644
--- a/llvm/test/tools/llvm-dlltool/coff-noname.def
+++ b/llvm/test/tools/llvm-dlltool/coff-noname.def
@@ -12,5 +12,6 @@ ByNameFunction
 ; CHECK-NEXT: Symbol: __imp__ByOrdinalFunction
 ; CHECK-NEXT: Symbol: _ByOrdinalFunction
 ; CHECK:      Name type: noprefix
+; CHECK-NEXT: Export name: ByNameFunction
 ; CHECK-NEXT: Symbol: __imp__ByNameFunction
 ; CHECK-NEXT: Symbol: _ByNameFunction
diff --git a/llvm/test/tools/llvm-dlltool/no-leading-underscore.def b/llvm/test/tools/llvm-dlltool/no-leading-underscore.def
index 6b78e15d2b5f69..9c5e77ca29a821 100644
--- a/llvm/test/tools/llvm-dlltool/no-leading-underscore.def
+++ b/llvm/test/tools/llvm-dlltool/no-leading-underscore.def
@@ -9,9 +9,11 @@ alias == func
 DecoratedFunction at 4
 
 ; CHECK:      Name type: name
+; CHECK-NEXT: Export name: func
 ; CHECK-NEXT: Symbol: __imp_func
 ; CHECK-NEXT: Symbol: func
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: DecoratedFunction
 ; CHECK-NEXT: Symbol: __imp_DecoratedFunction at 4
 ; CHECK-NEXT: Symbol: DecoratedFunction at 4
 
diff --git a/llvm/test/tools/llvm-lib/arm64ec-implib.test b/llvm/test/tools/llvm-lib/arm64ec-implib.test
index 2672f8d38b7f70..4250c775daa601 100644
--- a/llvm/test/tools/llvm-lib/arm64ec-implib.test
+++ b/llvm/test/tools/llvm-lib/arm64ec-implib.test
@@ -36,6 +36,7 @@ READOBJ-NEXT: File: test.dll
 READOBJ-NEXT: Format: COFF-import-file-ARM64EC
 READOBJ-NEXT: Type: code
 READOBJ-NEXT: Name type: name
+READOBJ-NEXT: Export name: funcexp
 READOBJ-NEXT: Symbol: __imp_funcexp
 READOBJ-NEXT: Symbol: funcexp
 READOBJ-EMPTY:
@@ -43,6 +44,7 @@ READOBJ-NEXT: File: test.dll
 READOBJ-NEXT: Format: COFF-import-file-ARM64EC
 READOBJ-NEXT: Type: data
 READOBJ-NEXT: Name type: name
+READOBJ-NEXT: Export name: dataexp
 READOBJ-NEXT: Symbol: __imp_dataexp
 
 Creating a new lib containing the existing lib:
diff --git a/llvm/test/tools/llvm-readobj/COFF/file-headers.test b/llvm/test/tools/llvm-readobj/COFF/file-headers.test
index b83a6cf5b972b3..32f39e196b0001 100644
--- a/llvm/test/tools/llvm-readobj/COFF/file-headers.test
+++ b/llvm/test/tools/llvm-readobj/COFF/file-headers.test
@@ -323,6 +323,7 @@ symbols:
 #      IMPORTLIB:Format: COFF-import-file-i386
 # IMPORTLIB-NEXT:Type: code
 # IMPORTLIB-NEXT:Name type: noprefix
+# IMPORTLIB-NEXT:Export name: func
 # IMPORTLIB-NEXT:Symbol: __imp__func
 # IMPORTLIB-NEXT:Symbol: _func
 # IMPORTLIB-NOT:{{.}}
diff --git a/llvm/tools/llvm-readobj/COFFImportDumper.cpp b/llvm/tools/llvm-readobj/COFFImportDumper.cpp
index 8aedc310ae3a9f..656ca32f03a77d 100644
--- a/llvm/tools/llvm-readobj/COFFImportDumper.cpp
+++ b/llvm/tools/llvm-readobj/COFFImportDumper.cpp
@@ -47,6 +47,9 @@ void dumpCOFFImportFile(const COFFImportFile *File, ScopedPrinter &Writer) {
     break;
   }
 
+  if (H->getNameType() != COFF::IMPORT_ORDINAL)
+    Writer.printString("Export name", File->getExportName());
+
   for (const object::BasicSymbolRef &Sym : File->symbols()) {
     raw_ostream &OS = Writer.startLine();
     OS << "Symbol: ";

>From 8c18de9e2e15d7dcf76844b907c7d347bc01f0ae Mon Sep 17 00:00:00 2001
From: Jacek Caban <jacek at codeweavers.com>
Date: Sat, 10 Feb 2024 01:00:14 +0100
Subject: [PATCH 2/4] [llvm-lib][llvm-dlltool][Object] Add support for EXPORTAS
 name types. (#78772)

EXPORTAS is a new name type in import libraries. It's used by default on ARM64EC,
but it's allowed on other platforms as well.
---
 llvm/include/llvm/BinaryFormat/COFF.h        |  5 +-
 llvm/include/llvm/Object/COFFImportFile.h    |  4 +
 llvm/lib/Object/COFFImportFile.cpp           | 66 +++++++++-----
 llvm/lib/Object/COFFModuleDefinition.cpp     | 13 ++-
 llvm/test/tools/llvm-lib/exportas.test       | 94 ++++++++++++++++++++
 llvm/tools/llvm-readobj/COFFImportDumper.cpp |  3 +
 6 files changed, 162 insertions(+), 23 deletions(-)
 create mode 100644 llvm/test/tools/llvm-lib/exportas.test

diff --git a/llvm/include/llvm/BinaryFormat/COFF.h b/llvm/include/llvm/BinaryFormat/COFF.h
index 522ee37da6e830..72461d0d9c316a 100644
--- a/llvm/include/llvm/BinaryFormat/COFF.h
+++ b/llvm/include/llvm/BinaryFormat/COFF.h
@@ -716,7 +716,10 @@ enum ImportNameType : unsigned {
   IMPORT_NAME_NOPREFIX = 2,
   /// The import name is the public symbol name, but skipping the leading ?,
   /// @, or optionally _, and truncating at the first @.
-  IMPORT_NAME_UNDECORATE = 3
+  IMPORT_NAME_UNDECORATE = 3,
+  /// The import name is specified as a separate string in the import library
+  /// object file.
+  IMPORT_NAME_EXPORTAS = 4
 };
 
 enum class GuardFlags : uint32_t {
diff --git a/llvm/include/llvm/Object/COFFImportFile.h b/llvm/include/llvm/Object/COFFImportFile.h
index 45a4a795fd1903..7c5846e9c044e3 100644
--- a/llvm/include/llvm/Object/COFFImportFile.h
+++ b/llvm/include/llvm/Object/COFFImportFile.h
@@ -92,6 +92,10 @@ struct COFFShortExport {
   /// file, this is "baz" in "EXPORTS\nfoo = bar == baz".
   std::string AliasTarget;
 
+  /// Specifies EXPORTAS name. In a .def file, this is "bar" in
+  /// "EXPORTS\nfoo EXPORTAS bar".
+  std::string ExportAs;
+
   uint16_t Ordinal = 0;
   bool Noname = false;
   bool Data = false;
diff --git a/llvm/lib/Object/COFFImportFile.cpp b/llvm/lib/Object/COFFImportFile.cpp
index d7d26f4f4180c3..51e6274dcf235c 100644
--- a/llvm/lib/Object/COFFImportFile.cpp
+++ b/llvm/lib/Object/COFFImportFile.cpp
@@ -71,6 +71,12 @@ StringRef COFFImportFile::getExportName() const {
     name = ltrim1(name, "?@_");
     name = name.substr(0, name.find('@'));
     break;
+  case IMPORT_NAME_EXPORTAS: {
+    // Skip DLL name
+    name = Data.getBuffer().substr(sizeof(*hdr) + name.size() + 1);
+    name = name.split('\0').second.split('\0').first;
+    break;
+  }
   default:
     break;
   }
@@ -209,6 +215,7 @@ class ObjectFactory {
   // Library Format.
   NewArchiveMember createShortImport(StringRef Sym, uint16_t Ordinal,
                                      ImportType Type, ImportNameType NameType,
+                                     StringRef ExportName,
                                      MachineTypes Machine);
 
   // Create a weak external file which is described in PE/COFF Aux Format 3.
@@ -500,12 +507,13 @@ NewArchiveMember ObjectFactory::createNullThunk(std::vector<uint8_t> &Buffer) {
   return {MemoryBufferRef{F, ImportName}};
 }
 
-NewArchiveMember ObjectFactory::createShortImport(StringRef Sym,
-                                                  uint16_t Ordinal,
-                                                  ImportType ImportType,
-                                                  ImportNameType NameType,
-                                                  MachineTypes Machine) {
+NewArchiveMember
+ObjectFactory::createShortImport(StringRef Sym, uint16_t Ordinal,
+                                 ImportType ImportType, ImportNameType NameType,
+                                 StringRef ExportName, MachineTypes Machine) {
   size_t ImpSize = ImportName.size() + Sym.size() + 2; // +2 for NULs
+  if (!ExportName.empty())
+    ImpSize += ExportName.size() + 1;
   size_t Size = sizeof(coff_import_header) + ImpSize;
   char *Buf = Alloc.Allocate<char>(Size);
   memset(Buf, 0, Size);
@@ -525,6 +533,10 @@ NewArchiveMember ObjectFactory::createShortImport(StringRef Sym,
   memcpy(P, Sym.data(), Sym.size());
   P += Sym.size() + 1;
   memcpy(P, ImportName.data(), ImportName.size());
+  if (!ExportName.empty()) {
+    P += ImportName.size() + 1;
+    memcpy(P, ExportName.data(), ExportName.size());
+  }
 
   return {MemoryBufferRef(StringRef(Buf, Size), ImportName)};
 }
@@ -641,27 +653,39 @@ Error writeImportLibrary(StringRef ImportName, StringRef Path,
       ImportType = IMPORT_CONST;
 
     StringRef SymbolName = E.SymbolName.empty() ? E.Name : E.SymbolName;
-    ImportNameType NameType = E.Noname
-                                  ? IMPORT_ORDINAL
-                                  : getNameType(SymbolName, E.Name,
-                                                Machine, MinGW);
-    Expected<std::string> Name = E.ExtName.empty()
-                                     ? std::string(SymbolName)
-                                     : replace(SymbolName, E.Name, E.ExtName);
-
-    if (!Name)
-      return Name.takeError();
-
-    if (!E.AliasTarget.empty() && *Name != E.AliasTarget) {
+    std::string Name;
+
+    if (E.ExtName.empty()) {
+      Name = std::string(SymbolName);
+    } else {
+      Expected<std::string> ReplacedName =
+          replace(SymbolName, E.Name, E.ExtName);
+      if (!ReplacedName)
+        return ReplacedName.takeError();
+      Name.swap(*ReplacedName);
+    }
+
+    if (!E.AliasTarget.empty() && Name != E.AliasTarget) {
       Members.push_back(
-          OF.createWeakExternal(E.AliasTarget, *Name, false, Machine));
+          OF.createWeakExternal(E.AliasTarget, Name, false, Machine));
       Members.push_back(
-          OF.createWeakExternal(E.AliasTarget, *Name, true, Machine));
+          OF.createWeakExternal(E.AliasTarget, Name, true, Machine));
       continue;
     }
 
-    Members.push_back(
-        OF.createShortImport(*Name, E.Ordinal, ImportType, NameType, Machine));
+    ImportNameType NameType;
+    std::string ExportName;
+    if (E.Noname) {
+      NameType = IMPORT_ORDINAL;
+    } else if (!E.ExportAs.empty()) {
+      NameType = IMPORT_NAME_EXPORTAS;
+      ExportName = E.ExportAs;
+    } else {
+      NameType = getNameType(SymbolName, E.Name, Machine, MinGW);
+    }
+
+    Members.push_back(OF.createShortImport(Name, E.Ordinal, ImportType,
+                                           NameType, ExportName, Machine));
   }
 
   return writeArchive(Path, Members, SymtabWritingMode::NormalSymtab,
diff --git a/llvm/lib/Object/COFFModuleDefinition.cpp b/llvm/lib/Object/COFFModuleDefinition.cpp
index 648f01f823d007..f60dd49793685f 100644
--- a/llvm/lib/Object/COFFModuleDefinition.cpp
+++ b/llvm/lib/Object/COFFModuleDefinition.cpp
@@ -39,6 +39,7 @@ enum Kind {
   KwConstant,
   KwData,
   KwExports,
+  KwExportAs,
   KwHeapsize,
   KwLibrary,
   KwName,
@@ -118,6 +119,7 @@ class Lexer {
                    .Case("CONSTANT", KwConstant)
                    .Case("DATA", KwData)
                    .Case("EXPORTS", KwExports)
+                   .Case("EXPORTAS", KwExportAs)
                    .Case("HEAPSIZE", KwHeapsize)
                    .Case("LIBRARY", KwLibrary)
                    .Case("NAME", KwName)
@@ -286,7 +288,16 @@ class Parser {
           E.AliasTarget = std::string("_").append(E.AliasTarget);
         continue;
       }
-      unget();
+      // EXPORTAS must be at the end of export definition
+      if (Tok.K == KwExportAs) {
+        read();
+        if (Tok.K == Eof)
+          return createError(
+              "unexpected end of file, EXPORTAS identifier expected");
+        E.ExportAs = std::string(Tok.Value);
+      } else {
+        unget();
+      }
       Info.Exports.push_back(E);
       return Error::success();
     }
diff --git a/llvm/test/tools/llvm-lib/exportas.test b/llvm/test/tools/llvm-lib/exportas.test
new file mode 100644
index 00000000000000..f6e845ca174664
--- /dev/null
+++ b/llvm/test/tools/llvm-lib/exportas.test
@@ -0,0 +1,94 @@
+Test EXPORTAS in importlibs.
+
+RUN: split-file %s %t.dir && cd %t.dir
+RUN: llvm-lib -machine:amd64 -def:test.def -out:test.lib
+
+RUN: llvm-nm --print-armap test.lib | FileCheck --check-prefix=ARMAP %s
+
+ARMAP:      Archive map
+ARMAP-NEXT: __IMPORT_DESCRIPTOR_test in test.dll
+ARMAP-NEXT: __NULL_IMPORT_DESCRIPTOR in test.dll
+ARMAP-NEXT: __imp_func in test.dll
+ARMAP-NEXT: __imp_func2 in test.dll
+ARMAP-NEXT: __imp_func3 in test.dll
+ARMAP-NEXT: __imp_mydata in test.dll
+ARMAP-NEXT: func in test.dll
+ARMAP-NEXT: func2 in test.dll
+ARMAP-NEXT: func3 in test.dll
+ARMAP-NEXT: test_NULL_THUNK_DATA in test.dll
+
+RUN: llvm-readobj test.lib | FileCheck --check-prefix=READOBJ %s
+
+READOBJ:      File: test.lib(test.dll)
+READOBJ-NEXT: Format: COFF-x86-64
+READOBJ-NEXT: Arch: x86_64
+READOBJ-NEXT: AddressSize: 64bit
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.lib(test.dll)
+READOBJ-NEXT: Format: COFF-x86-64
+READOBJ-NEXT: Arch: x86_64
+READOBJ-NEXT: AddressSize: 64bit
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.lib(test.dll)
+READOBJ-NEXT: Format: COFF-x86-64
+READOBJ-NEXT: Arch: x86_64
+READOBJ-NEXT: AddressSize: 64bit
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.dll
+READOBJ-NEXT: Format: COFF-import-file-x86-64
+READOBJ-NEXT: Type: code
+READOBJ-NEXT: Name type: export as
+READOBJ-NEXT: Export name: expfunc
+READOBJ-NEXT: Symbol: __imp_func
+READOBJ-NEXT: Symbol: func
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.dll
+READOBJ-NEXT: Format: COFF-import-file-x86-64
+READOBJ-NEXT: Type: data
+READOBJ-NEXT: Name type: export as
+READOBJ-NEXT: Export name: expdata
+READOBJ-NEXT: Symbol: __imp_mydata
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.dll
+READOBJ-NEXT: Format: COFF-import-file-x86-64
+READOBJ-NEXT: Type: code
+READOBJ-NEXT: Name type: export as
+READOBJ-NEXT: Export name: expfunc2
+READOBJ-NEXT: Symbol: __imp_func2
+READOBJ-NEXT: Symbol: func2
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.dll
+READOBJ-NEXT: Format: COFF-import-file-x86-64
+READOBJ-NEXT: Type: code
+READOBJ-NEXT: Name type: export as
+READOBJ-NEXT: Export name: expfunc3
+READOBJ-NEXT: Symbol: __imp_func3
+READOBJ-NEXT: Symbol: func3
+
+
+EXPORTAS must be at the end of entry declaration.
+RUN: not llvm-lib -machine:amd64 -def:test2.def -out:test2.lib 2>&1 \
+RUN:              | FileCheck --check-prefix=ERROR %s
+RUN: not llvm-lib -machine:amd64 -def:test3.def -out:test3.lib 2>&1 \
+RUN:              | FileCheck --check-prefix=ERROR %s
+ERROR: Invalid data was encountered while parsing the file
+
+
+#--- test.def
+LIBRARY test.dll
+EXPORTS
+        func EXPORTAS expfunc
+        mydata DATA EXPORTAS expdata
+        func2 = myfunc2 EXPORTAS expfunc2
+        func3 = otherdll.otherfunc3 EXPORTAS expfunc3
+
+#--- test2.def
+LIBRARY test.dll
+EXPORTS
+        func EXPORTAS expfunc
+        mydata EXPORTAS expdata DATA
+
+#--- test3.def
+LIBRARY test.dll
+EXPORTS
+        mydata EXPORTAS
diff --git a/llvm/tools/llvm-readobj/COFFImportDumper.cpp b/llvm/tools/llvm-readobj/COFFImportDumper.cpp
index 656ca32f03a77d..0ab2a17655653e 100644
--- a/llvm/tools/llvm-readobj/COFFImportDumper.cpp
+++ b/llvm/tools/llvm-readobj/COFFImportDumper.cpp
@@ -45,6 +45,9 @@ void dumpCOFFImportFile(const COFFImportFile *File, ScopedPrinter &Writer) {
   case COFF::IMPORT_NAME_UNDECORATE:
     Writer.printString("Name type", "undecorate");
     break;
+  case COFF::IMPORT_NAME_EXPORTAS:
+    Writer.printString("Name type", "export as");
+    break;
   }
 
   if (H->getNameType() != COFF::IMPORT_ORDINAL)

>From 4f971c506912e747e5d4c5d9b7295a253c0a77e6 Mon Sep 17 00:00:00 2001
From: Jacek Caban <jacek at codeweavers.com>
Date: Sat, 10 Feb 2024 12:46:42 +0100
Subject: [PATCH 3/4] [llvm-lib][Object] Add support for EC importlib symbols.
 (#81059)

ARM64EC import libraries expose two additional symbols: mangled thunk
symbol (like `#func`) and auxiliary import symbol (like`__imp_aux_func`).
The main functional change with this patch is that those symbols are
properly added to static library ECSYMBOLS.
---
 llvm/include/llvm/Object/COFF.h               |  41 +++++
 llvm/include/llvm/Object/COFFImportFile.h     |  28 +++-
 llvm/lib/Object/COFFImportFile.cpp            |  15 ++
 .../AArch64/AArch64Arm64ECCallLowering.cpp    |   2 +
 .../lib/Target/AArch64/AArch64MCInstLower.cpp |   2 +
 .../Target/AArch64/Utils/AArch64BaseInfo.h    |  28 ----
 llvm/test/tools/llvm-lib/arm64ec-implib.test  | 141 +++++++++++++++++-
 7 files changed, 225 insertions(+), 32 deletions(-)

diff --git a/llvm/include/llvm/Object/COFF.h b/llvm/include/llvm/Object/COFF.h
index a548b2c15c5fdc..2a5c3d8913b15c 100644
--- a/llvm/include/llvm/Object/COFF.h
+++ b/llvm/include/llvm/Object/COFF.h
@@ -1362,6 +1362,47 @@ class SectionStrippedError
   SectionStrippedError() { setErrorCode(object_error::section_stripped); }
 };
 
+inline std::optional<std::string>
+getArm64ECMangledFunctionName(StringRef Name) {
+  bool IsCppFn = Name[0] == '?';
+  if (IsCppFn && Name.find("$$h") != std::string::npos)
+    return std::nullopt;
+  if (!IsCppFn && Name[0] == '#')
+    return std::nullopt;
+
+  StringRef Prefix = "$$h";
+  size_t InsertIdx = 0;
+  if (IsCppFn) {
+    InsertIdx = Name.find("@@");
+    size_t ThreeAtSignsIdx = Name.find("@@@");
+    if (InsertIdx != std::string::npos && InsertIdx != ThreeAtSignsIdx) {
+      InsertIdx += 2;
+    } else {
+      InsertIdx = Name.find("@");
+      if (InsertIdx != std::string::npos)
+        InsertIdx++;
+    }
+  } else {
+    Prefix = "#";
+  }
+
+  return std::optional<std::string>(
+      (Name.substr(0, InsertIdx) + Prefix + Name.substr(InsertIdx)).str());
+}
+
+inline std::optional<std::string>
+getArm64ECDemangledFunctionName(StringRef Name) {
+  if (Name[0] == '#')
+    return std::string(Name.substr(1));
+  if (Name[0] != '?')
+    return std::nullopt;
+
+  std::pair<StringRef, StringRef> Pair = Name.split("$$h");
+  if (Pair.second.empty())
+    return std::nullopt;
+  return (Pair.first + Pair.second).str();
+}
+
 } // end namespace object
 
 } // end namespace llvm
diff --git a/llvm/include/llvm/Object/COFFImportFile.h b/llvm/include/llvm/Object/COFFImportFile.h
index 7c5846e9c044e3..46a982ddb7eee6 100644
--- a/llvm/include/llvm/Object/COFFImportFile.h
+++ b/llvm/include/llvm/Object/COFFImportFile.h
@@ -27,6 +27,9 @@ namespace llvm {
 namespace object {
 
 class COFFImportFile : public SymbolicFile {
+private:
+  enum SymbolIndex { ImpSymbol, ThunkSymbol, ECAuxSymbol, ECThunkSymbol };
+
 public:
   COFFImportFile(MemoryBufferRef Source)
       : SymbolicFile(ID_COFFImportFile, Source) {}
@@ -36,9 +39,23 @@ class COFFImportFile : public SymbolicFile {
   void moveSymbolNext(DataRefImpl &Symb) const override { ++Symb.p; }
 
   Error printSymbolName(raw_ostream &OS, DataRefImpl Symb) const override {
-    if (Symb.p == 0)
+    switch (Symb.p) {
+    case ImpSymbol:
       OS << "__imp_";
-    OS << StringRef(Data.getBufferStart() + sizeof(coff_import_header));
+      break;
+    case ECAuxSymbol:
+      OS << "__imp_aux_";
+      break;
+    }
+    const char *Name = Data.getBufferStart() + sizeof(coff_import_header);
+    if (Symb.p != ECThunkSymbol && COFF::isArm64EC(getMachine())) {
+      if (std::optional<std::string> DemangledName =
+              getArm64ECDemangledFunctionName(Name)) {
+        OS << StringRef(*DemangledName);
+        return Error::success();
+      }
+    }
+    OS << StringRef(Name);
     return Error::success();
   }
 
@@ -52,7 +69,12 @@ class COFFImportFile : public SymbolicFile {
 
   basic_symbol_iterator symbol_end() const override {
     DataRefImpl Symb;
-    Symb.p = isData() ? 1 : 2;
+    if (isData())
+      Symb.p = ImpSymbol + 1;
+    else if (COFF::isArm64EC(getMachine()))
+      Symb.p = ECThunkSymbol + 1;
+    else
+      Symb.p = ThunkSymbol + 1;
     return BasicSymbolRef(Symb, this);
   }
 
diff --git a/llvm/lib/Object/COFFImportFile.cpp b/llvm/lib/Object/COFFImportFile.cpp
index 51e6274dcf235c..a3e5e78952c16a 100644
--- a/llvm/lib/Object/COFFImportFile.cpp
+++ b/llvm/lib/Object/COFFImportFile.cpp
@@ -684,6 +684,21 @@ Error writeImportLibrary(StringRef ImportName, StringRef Path,
       NameType = getNameType(SymbolName, E.Name, Machine, MinGW);
     }
 
+    // On ARM64EC, use EXPORTAS to import demangled name for mangled symbols.
+    if (ImportType == IMPORT_CODE && isArm64EC(Machine)) {
+      if (std::optional<std::string> MangledName =
+              getArm64ECMangledFunctionName(Name)) {
+        if (ExportName.empty()) {
+          NameType = IMPORT_NAME_EXPORTAS;
+          ExportName.swap(Name);
+        }
+        Name = std::move(*MangledName);
+      } else if (ExportName.empty()) {
+        NameType = IMPORT_NAME_EXPORTAS;
+        ExportName = std::move(*getArm64ECDemangledFunctionName(Name));
+      }
+    }
+
     Members.push_back(OF.createShortImport(Name, E.Ordinal, ImportType,
                                            NameType, ExportName, Machine));
   }
diff --git a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
index 03d641d04413ef..55c5bbc66a3f4f 100644
--- a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
@@ -24,11 +24,13 @@
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/InitializePasses.h"
+#include "llvm/Object/COFF.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/TargetParser/Triple.h"
 
 using namespace llvm;
+using namespace llvm::object;
 
 using OperandBundleDef = OperandBundleDefT<Value *>;
 
diff --git a/llvm/lib/Target/AArch64/AArch64MCInstLower.cpp b/llvm/lib/Target/AArch64/AArch64MCInstLower.cpp
index 1e12cf545fa777..37d621cd2f6580 100644
--- a/llvm/lib/Target/AArch64/AArch64MCInstLower.cpp
+++ b/llvm/lib/Target/AArch64/AArch64MCInstLower.cpp
@@ -23,11 +23,13 @@
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCStreamer.h"
+#include "llvm/Object/COFF.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
 #include "llvm/Target/TargetMachine.h"
 using namespace llvm;
+using namespace llvm::object;
 
 extern cl::opt<bool> EnableAArch64ELFLocalDynamicTLSGeneration;
 
diff --git a/llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h b/llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h
index 10e69655f77e10..8b32d593d2a812 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h
+++ b/llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h
@@ -248,34 +248,6 @@ static inline bool atomicBarrierDroppedOnZero(unsigned Opcode) {
   return false;
 }
 
-static inline std::optional<std::string>
-getArm64ECMangledFunctionName(std::string Name) {
-  bool IsCppFn = Name[0] == '?';
-  if (IsCppFn && Name.find("$$h") != std::string::npos)
-    return std::nullopt;
-  if (!IsCppFn && Name[0] == '#')
-    return std::nullopt;
-
-  StringRef Prefix = "$$h";
-  size_t InsertIdx = 0;
-  if (IsCppFn) {
-    InsertIdx = Name.find("@@");
-    size_t ThreeAtSignsIdx = Name.find("@@@");
-    if (InsertIdx != std::string::npos && InsertIdx != ThreeAtSignsIdx) {
-      InsertIdx += 2;
-    } else {
-      InsertIdx = Name.find("@");
-      if (InsertIdx != std::string::npos)
-        InsertIdx++;
-    }
-  } else {
-    Prefix = "#";
-  }
-
-  Name.insert(Name.begin() + InsertIdx, Prefix.begin(), Prefix.end());
-  return std::optional<std::string>(Name);
-}
-
 namespace AArch64CC {
 
 // The CondCodes constants map directly to the 4-bit encoding of the condition
diff --git a/llvm/test/tools/llvm-lib/arm64ec-implib.test b/llvm/test/tools/llvm-lib/arm64ec-implib.test
index 4250c775daa601..c583ef75b2b0aa 100644
--- a/llvm/test/tools/llvm-lib/arm64ec-implib.test
+++ b/llvm/test/tools/llvm-lib/arm64ec-implib.test
@@ -11,9 +11,23 @@ ARMAP-NEXT: __NULL_IMPORT_DESCRIPTOR in test.dll
 ARMAP-NEXT: test_NULL_THUNK_DATA in test.dll
 ARMAP-EMPTY:
 ARMAP-NEXT: Archive EC map
+ARMAP-NEXT: #expname in test.dll
+ARMAP-NEXT: #funcexp in test.dll
+ARMAP-NEXT: #mangledfunc in test.dll
+ARMAP-NEXT: ?test_cpp_func@@$$hYAHPEAX at Z in test.dll
+ARMAP-NEXT: ?test_cpp_func@@YAHPEAX at Z in test.dll
+ARMAP-NEXT: __imp_?test_cpp_func@@YAHPEAX at Z in test.dll
+ARMAP-NEXT: __imp_aux_?test_cpp_func@@YAHPEAX at Z in test.dll
+ARMAP-NEXT: __imp_aux_expname in test.dll
+ARMAP-NEXT: __imp_aux_funcexp in test.dll
+ARMAP-NEXT: __imp_aux_mangledfunc in test.dll
 ARMAP-NEXT: __imp_dataexp in test.dll
+ARMAP-NEXT: __imp_expname in test.dll
 ARMAP-NEXT: __imp_funcexp in test.dll
+ARMAP-NEXT: __imp_mangledfunc in test.dll
+ARMAP-NEXT: expname in test.dll
 ARMAP-NEXT: funcexp in test.dll
+ARMAP-NEXT: mangledfunc in test.dll
 
 RUN: llvm-readobj test.lib | FileCheck -check-prefix=READOBJ %s
 
@@ -35,10 +49,42 @@ READOBJ-EMPTY:
 READOBJ-NEXT: File: test.dll
 READOBJ-NEXT: Format: COFF-import-file-ARM64EC
 READOBJ-NEXT: Type: code
-READOBJ-NEXT: Name type: name
+READOBJ-NEXT: Name type: export as
 READOBJ-NEXT: Export name: funcexp
 READOBJ-NEXT: Symbol: __imp_funcexp
 READOBJ-NEXT: Symbol: funcexp
+READOBJ-NEXT: Symbol: __imp_aux_funcexp
+READOBJ-NEXT: Symbol: #funcexp
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.dll
+READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+READOBJ-NEXT: Type: code
+READOBJ-NEXT: Name type: export as
+READOBJ-NEXT: Export name: mangledfunc
+READOBJ-NEXT: Symbol: __imp_mangledfunc
+READOBJ-NEXT: Symbol: mangledfunc
+READOBJ-NEXT: Symbol: __imp_aux_mangledfunc
+READOBJ-NEXT: Symbol: #mangledfunc
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.dll
+READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+READOBJ-NEXT: Type: code
+READOBJ-NEXT: Name type: export as
+READOBJ-NEXT: Export name: ?test_cpp_func@@YAHPEAX at Z
+READOBJ-NEXT: Symbol: __imp_?test_cpp_func@@YAHPEAX at Z
+READOBJ-NEXT: Symbol: ?test_cpp_func@@YAHPEAX at Z
+READOBJ-NEXT: Symbol: __imp_aux_?test_cpp_func@@YAHPEAX at Z
+READOBJ-NEXT: Symbol: ?test_cpp_func@@$$hYAHPEAX at Z
+READOBJ-EMPTY:
+READOBJ-NEXT: File: test.dll
+READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+READOBJ-NEXT: Type: code
+READOBJ-NEXT: Name type: export as
+READOBJ-NEXT: Export name: expname
+READOBJ-NEXT: Symbol: __imp_expname
+READOBJ-NEXT: Symbol: expname
+READOBJ-NEXT: Symbol: __imp_aux_expname
+READOBJ-NEXT: Symbol: #expname
 READOBJ-EMPTY:
 READOBJ-NEXT: File: test.dll
 READOBJ-NEXT: Format: COFF-import-file-ARM64EC
@@ -51,8 +97,101 @@ Creating a new lib containing the existing lib:
 RUN: llvm-lib -machine:arm64ec test.lib -out:test2.lib
 RUN: llvm-nm --print-armap test2.lib | FileCheck -check-prefix=ARMAP %s
 
+
+RUN: llvm-lib -machine:arm64ec -def:exportas.def -out:exportas.lib
+RUN: llvm-nm --print-armap exportas.lib | FileCheck -check-prefix=EXPAS-ARMAP %s
+RUN: llvm-readobj exportas.lib | FileCheck -check-prefix=EXPAS-READOBJ %s
+
+EXPAS-ARMAP:      Archive EC map
+EXPAS-ARMAP-NEXT: #func1 in test.dll
+EXPAS-ARMAP-NEXT: #func2 in test.dll
+EXPAS-ARMAP-NEXT: #func3 in test.dll
+EXPAS-ARMAP-NEXT: #func4 in test.dll
+EXPAS-ARMAP-NEXT: __imp_aux_func1 in test.dll
+EXPAS-ARMAP-NEXT: __imp_aux_func2 in test.dll
+EXPAS-ARMAP-NEXT: __imp_aux_func3 in test.dll
+EXPAS-ARMAP-NEXT: __imp_aux_func4 in test.dll
+EXPAS-ARMAP-NEXT: __imp_data1 in test.dll
+EXPAS-ARMAP-NEXT: __imp_data2 in test.dll
+EXPAS-ARMAP-NEXT: __imp_func1 in test.dll
+EXPAS-ARMAP-NEXT: __imp_func2 in test.dll
+EXPAS-ARMAP-NEXT: __imp_func3 in test.dll
+EXPAS-ARMAP-NEXT: __imp_func4 in test.dll
+EXPAS-ARMAP-NEXT: func1 in test.dll
+EXPAS-ARMAP-NEXT: func2 in test.dll
+EXPAS-ARMAP-NEXT: func3 in test.dll
+EXPAS-ARMAP-NEXT: func4 in test.dll
+
+EXPAS-READOBJ:      File: test.dll
+EXPAS-READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+EXPAS-READOBJ-NEXT: Type: code
+EXPAS-READOBJ-NEXT: Name type: export as
+EXPAS-READOBJ-NEXT: Export name: func1
+EXPAS-READOBJ-NEXT: Symbol: __imp_func1
+EXPAS-READOBJ-NEXT: Symbol: func1
+EXPAS-READOBJ-NEXT: Symbol: __imp_aux_func1
+EXPAS-READOBJ-NEXT: Symbol: #func1
+EXPAS-READOBJ-EMPTY:
+EXPAS-READOBJ-NEXT: File: test.dll
+EXPAS-READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+EXPAS-READOBJ-NEXT: Type: code
+EXPAS-READOBJ-NEXT: Name type: export as
+EXPAS-READOBJ-NEXT: Export name: func2
+EXPAS-READOBJ-NEXT: Symbol: __imp_func2
+EXPAS-READOBJ-NEXT: Symbol: func2
+EXPAS-READOBJ-NEXT: Symbol: __imp_aux_func2
+EXPAS-READOBJ-NEXT: Symbol: #func2
+EXPAS-READOBJ-EMPTY:
+EXPAS-READOBJ-NEXT: File: test.dll
+EXPAS-READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+EXPAS-READOBJ-NEXT: Type: code
+EXPAS-READOBJ-NEXT: Name type: export as
+EXPAS-READOBJ-NEXT: Export name: #func3
+EXPAS-READOBJ-NEXT: Symbol: __imp_func3
+EXPAS-READOBJ-NEXT: Symbol: func3
+EXPAS-READOBJ-NEXT: Symbol: __imp_aux_func3
+EXPAS-READOBJ-NEXT: Symbol: #func3
+EXPAS-READOBJ-EMPTY:
+EXPAS-READOBJ-NEXT: File: test.dll
+EXPAS-READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+EXPAS-READOBJ-NEXT: Type: code
+EXPAS-READOBJ-NEXT: Name type: export as
+EXPAS-READOBJ-NEXT: Export name: #func4
+EXPAS-READOBJ-NEXT: Symbol: __imp_func4
+EXPAS-READOBJ-NEXT: Symbol: func4
+EXPAS-READOBJ-NEXT: Symbol: __imp_aux_func4
+EXPAS-READOBJ-NEXT: Symbol: #func4
+EXPAS-READOBJ-EMPTY:
+EXPAS-READOBJ-NEXT: File: test.dll
+EXPAS-READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+EXPAS-READOBJ-NEXT: Type: data
+EXPAS-READOBJ-NEXT: Name type: export as
+EXPAS-READOBJ-NEXT: Export name: #data1
+EXPAS-READOBJ-NEXT: Symbol: __imp_data1
+EXPAS-READOBJ-EMPTY:
+EXPAS-READOBJ-NEXT: File: test.dll
+EXPAS-READOBJ-NEXT: Format: COFF-import-file-ARM64EC
+EXPAS-READOBJ-NEXT: Type: data
+EXPAS-READOBJ-NEXT: Name type: export as
+EXPAS-READOBJ-NEXT: Export name: data2
+EXPAS-READOBJ-NEXT: Symbol: __imp_data2
+
+
 #--- test.def
 LIBRARY test.dll
 EXPORTS
     funcexp
+    #mangledfunc
+    ?test_cpp_func@@YAHPEAX at Z
+    expname=impname
     dataexp DATA
+
+#--- exportas.def
+LIBRARY test.dll
+EXPORTS
+    #func1 EXPORTAS func1
+    func2 EXPORTAS func2
+    func3 EXPORTAS #func3
+    #func4 EXPORTAS #func4
+    data1 DATA EXPORTAS #data1
+    #data2 DATA EXPORTAS data2

>From b630142a49755cfdb4519730180591e042d26946 Mon Sep 17 00:00:00 2001
From: Daniel Paoliello <danpao at microsoft.com>
Date: Tue, 12 Mar 2024 14:10:49 -0700
Subject: [PATCH 4/4] [Arm64EC] Copy import descriptors to the EC Map (#84834)

As noted in <https://github.com/llvm/llvm-project/pull/78537>, MSVC
places import descriptors in both the EC and regular map - that PR moved
the descriptors to ONLY the regular map, however this causes linking
errors when linking as Arm64EC:

```
bcryptprimitives.lib(bcryptprimitives.dll) : error LNK2001: unresolved external symbol __IMPORT_DESCRIPTOR_bcryptprimitives (EC Symbol)
```

This change copies import descriptors from the regular map to the EC
map, which fixes this linking error.
---
 llvm/include/llvm/Object/COFFImportFile.h    |  6 ++++++
 llvm/lib/Object/ArchiveWriter.cpp            | 11 +++++++++++
 llvm/lib/Object/COFFImportFile.cpp           | 10 ++++------
 llvm/test/tools/llvm-lib/arm64ec-implib.test |  6 ++++++
 4 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/Object/COFFImportFile.h b/llvm/include/llvm/Object/COFFImportFile.h
index 46a982ddb7eee6..c79ff18d3616ed 100644
--- a/llvm/include/llvm/Object/COFFImportFile.h
+++ b/llvm/include/llvm/Object/COFFImportFile.h
@@ -26,6 +26,12 @@
 namespace llvm {
 namespace object {
 
+constexpr std::string_view ImportDescriptorPrefix = "__IMPORT_DESCRIPTOR_";
+constexpr std::string_view NullImportDescriptorSymbolName =
+    "__NULL_IMPORT_DESCRIPTOR";
+constexpr std::string_view NullThunkDataPrefix = "\x7f";
+constexpr std::string_view NullThunkDataSuffix = "_NULL_THUNK_DATA";
+
 class COFFImportFile : public SymbolicFile {
 private:
   enum SymbolIndex { ImpSymbol, ThunkSymbol, ECAuxSymbol, ECThunkSymbol };
diff --git a/llvm/lib/Object/ArchiveWriter.cpp b/llvm/lib/Object/ArchiveWriter.cpp
index 155926a8c5949d..1a7ed2db543964 100644
--- a/llvm/lib/Object/ArchiveWriter.cpp
+++ b/llvm/lib/Object/ArchiveWriter.cpp
@@ -677,6 +677,13 @@ static bool isECObject(object::SymbolicFile &Obj) {
   return false;
 }
 
+bool isImportDescriptor(StringRef Name) {
+  return Name.starts_with(ImportDescriptorPrefix) ||
+         Name == StringRef{NullImportDescriptorSymbolName} ||
+         (Name.starts_with(NullThunkDataPrefix) &&
+          Name.ends_with(NullThunkDataSuffix));
+}
+
 static Expected<std::vector<unsigned>> getSymbols(SymbolicFile *Obj,
                                                   uint16_t Index,
                                                   raw_ostream &SymNames,
@@ -704,6 +711,10 @@ static Expected<std::vector<unsigned>> getSymbols(SymbolicFile *Obj,
       if (Map == &SymMap->Map) {
         Ret.push_back(SymNames.tell());
         SymNames << Name << '\0';
+        // If EC is enabled, then the import descriptors are NOT put into EC
+        // objects so we need to copy them to the EC map manually.
+        if (SymMap->UseECMap && isImportDescriptor(Name))
+          SymMap->ECMap[Name] = Index;
       }
     } else {
       Ret.push_back(SymNames.tell());
diff --git a/llvm/lib/Object/COFFImportFile.cpp b/llvm/lib/Object/COFFImportFile.cpp
index a3e5e78952c16a..99a42d8c4e06a5 100644
--- a/llvm/lib/Object/COFFImportFile.cpp
+++ b/llvm/lib/Object/COFFImportFile.cpp
@@ -108,7 +108,7 @@ template <class T> static void append(std::vector<uint8_t> &B, const T &Data) {
 }
 
 static void writeStringTable(std::vector<uint8_t> &B,
-                             ArrayRef<const std::string> Strings) {
+                             ArrayRef<const std::string_view> Strings) {
   // The COFF string table consists of a 4-byte value which is the size of the
   // table, including the length field itself.  This value is followed by the
   // string content itself, which is an array of null-terminated C-style
@@ -171,9 +171,6 @@ static Expected<std::string> replace(StringRef S, StringRef From,
   return (Twine(S.substr(0, Pos)) + To + S.substr(Pos + From.size())).str();
 }
 
-static const std::string NullImportDescriptorSymbolName =
-    "__NULL_IMPORT_DESCRIPTOR";
-
 namespace {
 // This class constructs various small object files necessary to support linking
 // symbols imported from a DLL.  The contents are pretty strictly defined and
@@ -192,8 +189,9 @@ class ObjectFactory {
 public:
   ObjectFactory(StringRef S, MachineTypes M)
       : NativeMachine(M), ImportName(S), Library(llvm::sys::path::stem(S)),
-        ImportDescriptorSymbolName(("__IMPORT_DESCRIPTOR_" + Library).str()),
-        NullThunkSymbolName(("\x7f" + Library + "_NULL_THUNK_DATA").str()) {}
+        ImportDescriptorSymbolName((ImportDescriptorPrefix + Library).str()),
+        NullThunkSymbolName(
+            (NullThunkDataPrefix + Library + NullThunkDataSuffix).str()) {}
 
   // Creates an Import Descriptor.  This is a small object file which contains a
   // reference to the terminators and contains the library name (entry) for the
diff --git a/llvm/test/tools/llvm-lib/arm64ec-implib.test b/llvm/test/tools/llvm-lib/arm64ec-implib.test
index c583ef75b2b0aa..52ac486da9e292 100644
--- a/llvm/test/tools/llvm-lib/arm64ec-implib.test
+++ b/llvm/test/tools/llvm-lib/arm64ec-implib.test
@@ -16,6 +16,8 @@ ARMAP-NEXT: #funcexp in test.dll
 ARMAP-NEXT: #mangledfunc in test.dll
 ARMAP-NEXT: ?test_cpp_func@@$$hYAHPEAX at Z in test.dll
 ARMAP-NEXT: ?test_cpp_func@@YAHPEAX at Z in test.dll
+ARMAP-NEXT: __IMPORT_DESCRIPTOR_test in test.dll
+ARMAP-NEXT: __NULL_IMPORT_DESCRIPTOR in test.dll
 ARMAP-NEXT: __imp_?test_cpp_func@@YAHPEAX at Z in test.dll
 ARMAP-NEXT: __imp_aux_?test_cpp_func@@YAHPEAX at Z in test.dll
 ARMAP-NEXT: __imp_aux_expname in test.dll
@@ -28,6 +30,7 @@ ARMAP-NEXT: __imp_mangledfunc in test.dll
 ARMAP-NEXT: expname in test.dll
 ARMAP-NEXT: funcexp in test.dll
 ARMAP-NEXT: mangledfunc in test.dll
+ARMAP-NEXT: test_NULL_THUNK_DATA in test.dll
 
 RUN: llvm-readobj test.lib | FileCheck -check-prefix=READOBJ %s
 
@@ -107,6 +110,8 @@ EXPAS-ARMAP-NEXT: #func1 in test.dll
 EXPAS-ARMAP-NEXT: #func2 in test.dll
 EXPAS-ARMAP-NEXT: #func3 in test.dll
 EXPAS-ARMAP-NEXT: #func4 in test.dll
+EXPAS-ARMAP-NEXT: __IMPORT_DESCRIPTOR_test in test.dll
+EXPAS-ARMAP-NEXT: __NULL_IMPORT_DESCRIPTOR in test.dll
 EXPAS-ARMAP-NEXT: __imp_aux_func1 in test.dll
 EXPAS-ARMAP-NEXT: __imp_aux_func2 in test.dll
 EXPAS-ARMAP-NEXT: __imp_aux_func3 in test.dll
@@ -121,6 +126,7 @@ EXPAS-ARMAP-NEXT: func1 in test.dll
 EXPAS-ARMAP-NEXT: func2 in test.dll
 EXPAS-ARMAP-NEXT: func3 in test.dll
 EXPAS-ARMAP-NEXT: func4 in test.dll
+EXPAS-ARMAP-NEXT: test_NULL_THUNK_DATA in test.dll
 
 EXPAS-READOBJ:      File: test.dll
 EXPAS-READOBJ-NEXT: Format: COFF-import-file-ARM64EC



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