[LLD][COFF] Use EC symbol table for exports defined in module definition files (#123849)

Author: cjacek

lld/COFF/Driver.cpp

@@ -30,7 +30,6 @@
 #include "llvm/LTO/LTO.h"
 #include "llvm/Object/ArchiveWriter.h"
 #include "llvm/Object/COFFImportFile.h"
-#include "llvm/Object/COFFModuleDefinition.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/Option.h"
@@ -1012,67 +1011,6 @@ void LinkerDriver::createImportLibrary(bool asLib) {
   }
 }
 
-void LinkerDriver::parseModuleDefs(StringRef path) {
-  llvm::TimeTraceScope timeScope("Parse def file");
-  std::unique_ptr<MemoryBuffer> mb =
-      CHECK(MemoryBuffer::getFile(path, /*IsText=*/false,
-                                  /*RequiresNullTerminator=*/false,
-                                  /*IsVolatile=*/true),
-            "could not open " + path);
-  COFFModuleDefinition m = check(parseCOFFModuleDefinition(
-      mb->getMemBufferRef(), ctx.config.machine, ctx.config.mingw));
-
-  // Include in /reproduce: output if applicable.
-  ctx.driver.takeBuffer(std::move(mb));
-
-  if (ctx.config.outputFile.empty())
-    ctx.config.outputFile = std::string(saver().save(m.OutputFile));
-  ctx.config.importName = std::string(saver().save(m.ImportName));
-  if (m.ImageBase)
-    ctx.config.imageBase = m.ImageBase;
-  if (m.StackReserve)
-    ctx.config.stackReserve = m.StackReserve;
-  if (m.StackCommit)
-    ctx.config.stackCommit = m.StackCommit;
-  if (m.HeapReserve)
-    ctx.config.heapReserve = m.HeapReserve;
-  if (m.HeapCommit)
-    ctx.config.heapCommit = m.HeapCommit;
-  if (m.MajorImageVersion)
-    ctx.config.majorImageVersion = m.MajorImageVersion;
-  if (m.MinorImageVersion)
-    ctx.config.minorImageVersion = m.MinorImageVersion;
-  if (m.MajorOSVersion)
-    ctx.config.majorOSVersion = m.MajorOSVersion;
-  if (m.MinorOSVersion)
-    ctx.config.minorOSVersion = m.MinorOSVersion;
-
-  for (COFFShortExport e1 : m.Exports) {
-    Export e2;
-    // Renamed exports are parsed and set as "ExtName = Name". If Name has
-    // the form "OtherDll.Func", it shouldn't be a normal exported
-    // function but a forward to another DLL instead. This is supported
-    // by both MS and GNU linkers.
-    if (!e1.ExtName.empty() && e1.ExtName != e1.Name &&
-        StringRef(e1.Name).contains('.')) {
-      e2.name = saver().save(e1.ExtName);
-      e2.forwardTo = saver().save(e1.Name);
-    } else {
-      e2.name = saver().save(e1.Name);
-      e2.extName = saver().save(e1.ExtName);
-    }
-    e2.exportAs = saver().save(e1.ExportAs);
-    e2.importName = saver().save(e1.ImportName);
-    e2.ordinal = e1.Ordinal;
-    e2.noname = e1.Noname;
-    e2.data = e1.Data;
-    e2.isPrivate = e1.Private;
-    e2.constant = e1.Constant;
-    e2.source = ExportSource::ModuleDefinition;
-    ctx.symtab.exports.push_back(e2);
-  }
-}
-
 void LinkerDriver::enqueueTask(std::function<void()> task) {
   taskQueue.push_back(std::move(task));
 }
@@ -2352,7 +2290,7 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
   // Handle /def
   if (auto *arg = args.getLastArg(OPT_deffile)) {
     // parseModuleDefs mutates Config object.
-    parseModuleDefs(arg->getValue());
+    mainSymtab.parseModuleDefs(arg->getValue());
   }
 
   // Handle generation of import library from a def file.

lld/COFF/Driver.h

@@ -143,8 +143,6 @@ class LinkerDriver {
   // Used by the resolver to parse .drectve section contents.
   void parseDirectives(InputFile *file);
 
-  void parseModuleDefs(StringRef path);
-
   // Parse an /order file. If an option is given, the linker places COMDAT
   // sections int he same order as their names appear in the given file.
   void parseOrderFile(StringRef arg);

lld/COFF/SymbolTable.cpp

@@ -20,6 +20,7 @@
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/LTO/LTO.h"
+#include "llvm/Object/COFFModuleDefinition.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/GlobPattern.h"
 #include "llvm/Support/Parallel.h"
@@ -29,6 +30,7 @@
 
 using namespace llvm;
 using namespace llvm::COFF;
+using namespace llvm::object;
 using namespace llvm::support;
 
 namespace lld::coff {
@@ -1253,6 +1255,67 @@ void SymbolTable::assignExportOrdinals() {
                << Twine(std::numeric_limits<uint16_t>::max()) << ")";
 }
 
+void SymbolTable::parseModuleDefs(StringRef path) {
+  llvm::TimeTraceScope timeScope("Parse def file");
+  std::unique_ptr<MemoryBuffer> mb =
+      CHECK(MemoryBuffer::getFile(path, /*IsText=*/false,
+                                  /*RequiresNullTerminator=*/false,
+                                  /*IsVolatile=*/true),
+            "could not open " + path);
+  COFFModuleDefinition m = check(parseCOFFModuleDefinition(
+      mb->getMemBufferRef(), machine, ctx.config.mingw));
+
+  // Include in /reproduce: output if applicable.
+  ctx.driver.takeBuffer(std::move(mb));
+
+  if (ctx.config.outputFile.empty())
+    ctx.config.outputFile = std::string(saver().save(m.OutputFile));
+  ctx.config.importName = std::string(saver().save(m.ImportName));
+  if (m.ImageBase)
+    ctx.config.imageBase = m.ImageBase;
+  if (m.StackReserve)
+    ctx.config.stackReserve = m.StackReserve;
+  if (m.StackCommit)
+    ctx.config.stackCommit = m.StackCommit;
+  if (m.HeapReserve)
+    ctx.config.heapReserve = m.HeapReserve;
+  if (m.HeapCommit)
+    ctx.config.heapCommit = m.HeapCommit;
+  if (m.MajorImageVersion)
+    ctx.config.majorImageVersion = m.MajorImageVersion;
+  if (m.MinorImageVersion)
+    ctx.config.minorImageVersion = m.MinorImageVersion;
+  if (m.MajorOSVersion)
+    ctx.config.majorOSVersion = m.MajorOSVersion;
+  if (m.MinorOSVersion)
+    ctx.config.minorOSVersion = m.MinorOSVersion;
+
+  for (COFFShortExport e1 : m.Exports) {
+    Export e2;
+    // Renamed exports are parsed and set as "ExtName = Name". If Name has
+    // the form "OtherDll.Func", it shouldn't be a normal exported
+    // function but a forward to another DLL instead. This is supported
+    // by both MS and GNU linkers.
+    if (!e1.ExtName.empty() && e1.ExtName != e1.Name &&
+        StringRef(e1.Name).contains('.')) {
+      e2.name = saver().save(e1.ExtName);
+      e2.forwardTo = saver().save(e1.Name);
+    } else {
+      e2.name = saver().save(e1.Name);
+      e2.extName = saver().save(e1.ExtName);
+    }
+    e2.exportAs = saver().save(e1.ExportAs);
+    e2.importName = saver().save(e1.ImportName);
+    e2.ordinal = e1.Ordinal;
+    e2.noname = e1.Noname;
+    e2.data = e1.Data;
+    e2.isPrivate = e1.Private;
+    e2.constant = e1.Constant;
+    e2.source = ExportSource::ModuleDefinition;
+    exports.push_back(e2);
+  }
+}
+
 Symbol *SymbolTable::addUndefined(StringRef name) {
   return addUndefined(name, nullptr, false);
 }

lld/COFF/SymbolTable.h

@@ -160,6 +160,7 @@ class SymbolTable {
 
   void fixupExports();
   void assignExportOrdinals();
+  void parseModuleDefs(StringRef path);
 
   // Iterates symbols in non-determinstic hash table order.
   template <typename T> void forEachSymbol(T callback) {

lld/test/COFF/arm64x-export.test

@@ -55,6 +55,13 @@ RUN:          loadconfig-arm64.obj loadconfig-arm64ec.obj arm64ec-drectve.obj -n
 RUN: llvm-objdump -d out-drectve-ec.dll | FileCheck --check-prefix=DISASM-EC %s
 RUN: llvm-readobj --headers --coff-exports out-drectve-ec.dll | FileCheck --check-prefix=EXPORTS-EC %s
 
+# A command-line def file applies only to EC exports.
+
+RUN: lld-link -machine:arm64x -dll -out:out-def-ec.dll arm64ec-func.obj arm64-func.obj \
+RUN:          loadconfig-arm64.obj loadconfig-arm64ec.obj -def:func.def -noentry
+RUN: llvm-objdump -d out-def-ec.dll | FileCheck --check-prefix=DISASM-EC %s
+RUN: llvm-readobj --headers --coff-exports out-def-ec.dll | FileCheck --check-prefix=EXPORTS-EC %s
+
 # Export using the EC .edata section.
 
 RUN: lld-link -machine:arm64x -dll -out:out-edata-ec.dll arm64ec-func.obj arm64-func.obj \
@@ -227,3 +234,8 @@ funcname_func:
 
 name:
     .asciz "out-edata.dll"
+
+#--- func.def
+LIBRARY out.dll
+EXPORTS
+        func