Backport fixes for ARM64EC import libraries #84590

dpaoliello · 2024-03-09T00:51:27Z

Backports fixes to be able to generate import libraries for ARM64EC:

There is one modification to these commits: we removed support for EXPORTAS in def files to maintain ABI compatibility for the COFFShortExport struct.

llvmbot · 2024-03-09T00:51:58Z

@llvm/pr-subscribers-lld-coff
@llvm/pr-subscribers-lld

@llvm/pr-subscribers-backend-aarch64

Author: Daniel Paoliello (dpaoliello)

Changes

Backports fixes to be able to generate import libraries for ARM64EC:

Patch is 32.86 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/84590.diff

19 Files Affected:

(modified) lld/test/COFF/def-export-cpp.s (+1)
(modified) lld/test/COFF/def-export-stdcall.s (+13)
(modified) lld/test/COFF/dllexport.s (+4)
(modified) llvm/include/llvm/BinaryFormat/COFF.h (+4-1)
(modified) llvm/include/llvm/Object/COFF.h (+41)
(modified) llvm/include/llvm/Object/COFFImportFile.h (+30-3)
(modified) llvm/lib/Object/COFFImportFile.cpp (+86-21)
(modified) llvm/lib/Object/COFFModuleDefinition.cpp (+12-1)
(modified) llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp (+2)
(modified) llvm/lib/Target/AArch64/AArch64MCInstLower.cpp (+2)
(modified) llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h (-28)
(modified) llvm/test/tools/llvm-dlltool/coff-decorated.def (+7)
(modified) llvm/test/tools/llvm-dlltool/coff-exports.def (+3)
(modified) llvm/test/tools/llvm-dlltool/coff-noname.def (+1)
(modified) llvm/test/tools/llvm-dlltool/no-leading-underscore.def (+2)
(modified) llvm/test/tools/llvm-lib/arm64ec-implib.test (+142-1)
(added) llvm/test/tools/llvm-lib/exportas.test (+94)
(modified) llvm/test/tools/llvm-readobj/COFF/file-headers.test (+1)
(modified) llvm/tools/llvm-readobj/COFFImportDumper.cpp (+6)

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@Z
 # IMPLIB-NEXT: Symbol: ?GetPathOnDisk@@YA_NPEA_W@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_@fastcall@8
 # UNDECORATED-IMPLIB-NEXT: fastcall@8
 # UNDECORATED-IMPLIB: Name type: undecorate
+# UNDECORATED-IMPLIB-NEXT: Export name: stdcall
 # UNDECORATED-IMPLIB-NEXT: __imp__stdcall@8
 # UNDECORATED-IMPLIB-NEXT: _stdcall@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@8
 # DECORATED-IMPLIB-NEXT: __imp_@fastcall@8
 # DECORATED-IMPLIB-NEXT: @fastcall@8
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: _stdcall@8
 # DECORATED-IMPLIB-NEXT: __imp__stdcall@8
 # DECORATED-IMPLIB-NEXT: _stdcall@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@8
 # DECORATED-MINGW-IMPLIB-NEXT: __imp_@fastcall@8
 # DECORATED-MINGW-IMPLIB-NEXT: fastcall@8
 # DECORATED-MINGW-IMPLIB: Name type: noprefix
+# DECORATED-MINGW-IMPLIB-NEXT: Export name: stdcall@8
 # DECORATED-MINGW-IMPLIB-NEXT: __imp__stdcall@8
 # DECORATED-MINGW-IMPLIB-NEXT: _stdcall@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@8
 # DECORATED-IMPLIB-NEXT: __imp_@fastcall@8
 # DECORATED-IMPLIB-NEXT: @fastcall@8
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: _stdcall@8
 # DECORATED-IMPLIB-NEXT: __imp__stdcall@8
 # DECORATED-IMPLIB-NEXT: _stdcall@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/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/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 edc836ff0348cb..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);
   }
 
@@ -66,6 +88,7 @@ class COFFImportFile : public SymbolicFile {
   uint16_t getMachine() const { return getCOFFImportHeader()->Machine; }
 
   StringRef getFileFormatName() const;
+  StringRef getExportName() const;
 
 private:
   bool isData() const {
@@ -91,6 +114,10 @@ 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 60556c149bf735..a3e5e78952c16a 100644
--- a/llvm/lib/Object/COFFImportFile.cpp
+++ b/llvm/lib/Object/COFFImportFile.cpp
@@ -52,6 +52,38 @@ 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;
+  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;
+  }
+
+  return name;
+}
+
 static uint16_t getImgRelRelocation(MachineTypes Machine) {
   switch (Machine) {
   default:
@@ -183,6 +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.
@@ -474,12 +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);
@@ -499,6 +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)};
 }
@@ -615,27 +653,54 @@ 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);
+    }
+
+    // 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));
   }
 
   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/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
index 11248bb7aef31f..e4449ff9a6aaf9 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-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@4=CdeclInternalFunction
 CdeclExportName=StdcallInternalFunction@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@4
 ; CHECK-NEXT: Symbol: _StdcallFunction@4
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: FastcallFunction
 ; CHECK-NEXT: Symbol: __imp_@FastcallFunction@4
 ; CHECK-NEXT: Symbol: @FastcallFunction@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@4
 ; CHECK-NM: U _StdcallFunction@4
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: StdcallExportName
 ; CHECK-NEXT: Symbol: __imp__StdcallExportName@4{{$}}
 ; CHECK-NEXT: Symbol: _StdcallExportName@4{{$}}
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: OtherStdcallExportName
 ; CHECK-NEXT: Symbol: __imp__OtherStdcallExportName@4{{$}}
 ; CHECK-NEXT: Symbol: _OtherStdcallExportName@4{{$}}
 ; CHECK...
[truncated]

llvmbot · 2024-03-09T00:51:58Z

@llvm/pr-subscribers-llvm-binary-utilities

Author: Daniel Paoliello (dpaoliello)

Changes

Backports fixes to be able to generate import libraries for ARM64EC:

Patch is 32.86 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/84590.diff

19 Files Affected:

(modified) lld/test/COFF/def-export-cpp.s (+1)
(modified) lld/test/COFF/def-export-stdcall.s (+13)
(modified) lld/test/COFF/dllexport.s (+4)
(modified) llvm/include/llvm/BinaryFormat/COFF.h (+4-1)
(modified) llvm/include/llvm/Object/COFF.h (+41)
(modified) llvm/include/llvm/Object/COFFImportFile.h (+30-3)
(modified) llvm/lib/Object/COFFImportFile.cpp (+86-21)
(modified) llvm/lib/Object/COFFModuleDefinition.cpp (+12-1)
(modified) llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp (+2)
(modified) llvm/lib/Target/AArch64/AArch64MCInstLower.cpp (+2)
(modified) llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h (-28)
(modified) llvm/test/tools/llvm-dlltool/coff-decorated.def (+7)
(modified) llvm/test/tools/llvm-dlltool/coff-exports.def (+3)
(modified) llvm/test/tools/llvm-dlltool/coff-noname.def (+1)
(modified) llvm/test/tools/llvm-dlltool/no-leading-underscore.def (+2)
(modified) llvm/test/tools/llvm-lib/arm64ec-implib.test (+142-1)
(added) llvm/test/tools/llvm-lib/exportas.test (+94)
(modified) llvm/test/tools/llvm-readobj/COFF/file-headers.test (+1)
(modified) llvm/tools/llvm-readobj/COFFImportDumper.cpp (+6)

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@Z
 # IMPLIB-NEXT: Symbol: ?GetPathOnDisk@@YA_NPEA_W@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_@fastcall@8
 # UNDECORATED-IMPLIB-NEXT: fastcall@8
 # UNDECORATED-IMPLIB: Name type: undecorate
+# UNDECORATED-IMPLIB-NEXT: Export name: stdcall
 # UNDECORATED-IMPLIB-NEXT: __imp__stdcall@8
 # UNDECORATED-IMPLIB-NEXT: _stdcall@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@8
 # DECORATED-IMPLIB-NEXT: __imp_@fastcall@8
 # DECORATED-IMPLIB-NEXT: @fastcall@8
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: _stdcall@8
 # DECORATED-IMPLIB-NEXT: __imp__stdcall@8
 # DECORATED-IMPLIB-NEXT: _stdcall@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@8
 # DECORATED-MINGW-IMPLIB-NEXT: __imp_@fastcall@8
 # DECORATED-MINGW-IMPLIB-NEXT: fastcall@8
 # DECORATED-MINGW-IMPLIB: Name type: noprefix
+# DECORATED-MINGW-IMPLIB-NEXT: Export name: stdcall@8
 # DECORATED-MINGW-IMPLIB-NEXT: __imp__stdcall@8
 # DECORATED-MINGW-IMPLIB-NEXT: _stdcall@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@8
 # DECORATED-IMPLIB-NEXT: __imp_@fastcall@8
 # DECORATED-IMPLIB-NEXT: @fastcall@8
 # DECORATED-IMPLIB: Name type: name
+# DECORATED-IMPLIB-NEXT: Export name: _stdcall@8
 # DECORATED-IMPLIB-NEXT: __imp__stdcall@8
 # DECORATED-IMPLIB-NEXT: _stdcall@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/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/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 edc836ff0348cb..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);
   }
 
@@ -66,6 +88,7 @@ class COFFImportFile : public SymbolicFile {
   uint16_t getMachine() const { return getCOFFImportHeader()->Machine; }
 
   StringRef getFileFormatName() const;
+  StringRef getExportName() const;
 
 private:
   bool isData() const {
@@ -91,6 +114,10 @@ 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 60556c149bf735..a3e5e78952c16a 100644
--- a/llvm/lib/Object/COFFImportFile.cpp
+++ b/llvm/lib/Object/COFFImportFile.cpp
@@ -52,6 +52,38 @@ 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;
+  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;
+  }
+
+  return name;
+}
+
 static uint16_t getImgRelRelocation(MachineTypes Machine) {
   switch (Machine) {
   default:
@@ -183,6 +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.
@@ -474,12 +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);
@@ -499,6 +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)};
 }
@@ -615,27 +653,54 @@ 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);
+    }
+
+    // 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));
   }
 
   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/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
index 11248bb7aef31f..e4449ff9a6aaf9 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-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@4=CdeclInternalFunction
 CdeclExportName=StdcallInternalFunction@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@4
 ; CHECK-NEXT: Symbol: _StdcallFunction@4
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: FastcallFunction
 ; CHECK-NEXT: Symbol: __imp_@FastcallFunction@4
 ; CHECK-NEXT: Symbol: @FastcallFunction@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@4
 ; CHECK-NM: U _StdcallFunction@4
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: StdcallExportName
 ; CHECK-NEXT: Symbol: __imp__StdcallExportName@4{{$}}
 ; CHECK-NEXT: Symbol: _StdcallExportName@4{{$}}
 ; CHECK:      Name type: undecorate
+; CHECK-NEXT: Export name: OtherStdcallExportName
 ; CHECK-NEXT: Symbol: __imp__OtherStdcallExportName@4{{$}}
 ; CHECK-NEXT: Symbol: _OtherStdcallExportName@4{{$}}
 ; CHECK...
[truncated]

efriedma-quic · 2024-03-11T20:48:07Z

This seems like a pretty big change to backport... how useful is it in practice? I was under the impression that arm64ec lld support is still immature... and if you're using the MSVC linker, you might as well use the MSVC lib/dlltool.

dpaoliello · 2024-03-11T21:14:05Z

Blocking to wait for #84834

cjacek · 2024-03-11T21:17:19Z

I have similar feeling to @efriedma-quic . There is probably not much use of those fixes on their own. They are a step towards stand-alone toolchain and are required for the linker, both for its libs part and to generate test cases, but they alone are not enough. They will be more useful when paired with linker support, which I hope will be in a useful shape for LLVM 19. Until then MSVC is required anyway.

dpaoliello · 2024-03-11T21:28:44Z

Sorry, I've got to disagree with this: this is blocking Rust's use of Arm64EC since it can generate import libraries on-the-fly using this functionality (rather than requiring that users install the Windows SDK).

I've tested Arm64EC with Rust, and this is the only blocking issue that I've found.

efriedma-quic · 2024-03-11T23:01:27Z

So your use-case is basically equivalent to using llvm-dlltool, except not using the text parser?

If this is actually enough to make Rust targets usable, then I guess we could consider it, but the fixes aren't structured in a way to make it obvious this won't impact non-ARM64EC targets.

dpaoliello · 2024-03-12T00:08:14Z

So your use-case is basically equivalent to using llvm-dlltool, except not using the text parser?

Yep.

If this is actually enough to make Rust targets usable, then I guess we could consider it, but the fixes aren't structured in a way to make it obvious this won't impact non-ARM64EC targets.

That's fair enough.

@cjacek you have more experience in this area than I do - what's your confidence level with backporting these changes?

cjacek · 2024-03-12T10:51:29Z

It's great to hear that it's enough got Rust. I re-reviewed those commits for impact on non-ARM64EC target and I think it's safe enough.

One thing we could consider is to skip .def file parser part of it. The main downside of it would be that it would require skipping some tests too. Other than than that, it's unlikely to matter and I think that Rust calls writeImportLibrary directly anyway.

dpaoliello · 2024-03-12T21:31:45Z

#84834 has been merged into master and cherry-picked here, so this is ready to land.

One thing we could consider is to skip .def file parser part of it.

I'd rather not modify commits since they've already been tested in master and it makes subsequent cherry-picks more difficult.

dpaoliello · 2024-03-13T16:14:58Z

@cjacek if you really want me to revert the def parser portion, then I can do that. Otherwise, can you please sign off?

cjacek

I think it's fine to keep it, thanks.

llvm/include/llvm/Object/COFFImportFile.h

dpaoliello · 2024-03-13T23:01:05Z

@tstellar I'd like to get this merged into the v18 release branch, but there's some discussion of whether we should trim the changes down to just what is needed or leave them as they were merged into master. Can you please let me know what your preference is?

dpaoliello · 2024-03-14T14:45:31Z

@tstellar change made as requested, this is now ready to merge

…name. (llvm#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.

…llvm#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.

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.

As noted in <llvm#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.

…y for COFFShortExport

dpaoliello requested review from cjacek and efriedma-quic March 9, 2024 00:51

llvmbot added lld backend:AArch64 lld:COFF llvm:binary-utilities labels Mar 9, 2024

dpaoliello force-pushed the arm64ecimplib branch from 8b6bc35 to 27e74d5 Compare March 12, 2024 21:29

dpaoliello force-pushed the arm64ecimplib branch from 27e74d5 to b630142 Compare March 13, 2024 16:13

cjacek approved these changes Mar 13, 2024

View reviewed changes

nikic added this to the LLVM 18.X Release milestone Mar 13, 2024

nikic reviewed Mar 13, 2024

View reviewed changes

llvm/include/llvm/Object/COFFImportFile.h Outdated Show resolved Hide resolved

dpaoliello force-pushed the arm64ecimplib branch from b630142 to f9d2b88 Compare March 13, 2024 23:19

dpaoliello force-pushed the arm64ecimplib branch from f9d2b88 to db5e157 Compare March 15, 2024 18:18

cjacek and others added 4 commits March 16, 2024 15:55

[llvm-lib][llvm-dlltool][Object] Add support for EXPORTAS name types. (…

76e1800

…llvm#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.

Remove support for EXPORTAS in def files to maintain ABI compatibilit…

2f640ad

…y for COFFShortExport

tstellar force-pushed the arm64ecimplib branch from db5e157 to 2f640ad Compare March 16, 2024 22:55

tstellar merged commit 2f640ad into llvm:release/18.x Mar 16, 2024
10 of 11 checks passed

dpaoliello deleted the arm64ecimplib branch March 18, 2024 17:29

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Backport fixes for ARM64EC import libraries #84590

Backport fixes for ARM64EC import libraries #84590

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Backport fixes for ARM64EC import libraries #84590

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