From 0e363b75a4dbfe1f48fb0c0f9866a0a0027d1374 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@google.com>
Date: Fri, 2 May 2014 03:43:51 +0000
Subject: [PATCH] [PECOFF] Support =internalName syntax in .def file.

Export definitions in a module definition file is as follows:

  exportedname[=internalname] [@ordinal [NONAME]] [PRIVATE] [DATA]

Previously we did not support =internalname, so users couldn't export
symbols from a DLL with a different name.

llvm-svn: 207827
---
 lld/include/lld/ReaderWriter/PECOFFLinkingContext.h |  2 +-
 lld/lib/Driver/WinLinkModuleDef.cpp                 | 11 +++++++++++
 lld/lib/ReaderWriter/PECOFF/EdataPass.cpp           |  3 ++-
 lld/lib/ReaderWriter/PECOFF/WriterImportLibrary.cpp |  2 +-
 lld/test/pecoff/Inputs/export.obj.yaml              |  6 ++++++
 lld/test/pecoff/Inputs/exports.def                  |  1 +
 lld/test/pecoff/export.test                         |  3 ++-
 7 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/lld/include/lld/ReaderWriter/PECOFFLinkingContext.h b/lld/include/lld/ReaderWriter/PECOFFLinkingContext.h
index 7283161a35ac..30bd0414e4be 100644
--- a/lld/include/lld/ReaderWriter/PECOFFLinkingContext.h
+++ b/lld/include/lld/ReaderWriter/PECOFFLinkingContext.h
@@ -67,7 +67,7 @@ public:
     }
 
     std::string name;
-    std::string internalName;
+    std::string externalName;
     int ordinal;
     bool noname;
     bool isData;
diff --git a/lld/lib/Driver/WinLinkModuleDef.cpp b/lld/lib/Driver/WinLinkModuleDef.cpp
index 61d3e967ba13..9992f92068f6 100644
--- a/lld/lib/Driver/WinLinkModuleDef.cpp
+++ b/lld/lib/Driver/WinLinkModuleDef.cpp
@@ -195,6 +195,17 @@ bool Parser::parseExport(PECOFFLinkingContext::ExportDesc &result) {
   }
   result.name = _tok._range;
 
+  consumeToken();
+  if (_tok._kind == Kind::equal) {
+    consumeToken();
+    if (_tok._kind != Kind::identifier)
+      return false;
+    result.externalName = result.name;
+    result.name = _tok._range;
+  } else {
+    ungetToken();
+  }
+
   for (;;) {
     consumeToken();
     if (_tok._kind == Kind::identifier && _tok._range[0] == '@') {
diff --git a/lld/lib/ReaderWriter/PECOFF/EdataPass.cpp b/lld/lib/ReaderWriter/PECOFF/EdataPass.cpp
index 8d6424138e72..cc5a003a4844 100644
--- a/lld/lib/ReaderWriter/PECOFF/EdataPass.cpp
+++ b/lld/lib/ReaderWriter/PECOFF/EdataPass.cpp
@@ -77,7 +77,8 @@ static bool getExportedAtoms(PECOFFLinkingContext &ctx, MutableFile *file,
     }
     const DefinedAtom *atom = it->second;
     ret.push_back(TableEntry(desc.name, desc.ordinal, atom, desc.noname));
-    desc.internalName = removeLeadingUnderscore(atom->name());
+    if (desc.externalName.empty())
+      desc.externalName = removeLeadingUnderscore(atom->name());
     exports.insert(desc);
   }
   ctx.getDllExports().swap(exports);
diff --git a/lld/lib/ReaderWriter/PECOFF/WriterImportLibrary.cpp b/lld/lib/ReaderWriter/PECOFF/WriterImportLibrary.cpp
index dec60dc1403e..77e2af43e031 100644
--- a/lld/lib/ReaderWriter/PECOFF/WriterImportLibrary.cpp
+++ b/lld/lib/ReaderWriter/PECOFF/WriterImportLibrary.cpp
@@ -30,7 +30,7 @@ createModuleDefinitionFile(const PECOFFLinkingContext &ctx) {
      << "EXPORTS\n";
 
   for (const PECOFFLinkingContext::ExportDesc &desc : ctx.getDllExports()) {
-    os << "  " << desc.internalName << " @" << desc.ordinal;
+    os << "  " << desc.externalName << " @" << desc.ordinal;
     if (desc.noname)
       os << " NONAME";
     if (desc.isData)
diff --git a/lld/test/pecoff/Inputs/export.obj.yaml b/lld/test/pecoff/Inputs/export.obj.yaml
index cd961862e411..f1c043f81966 100644
--- a/lld/test/pecoff/Inputs/export.obj.yaml
+++ b/lld/test/pecoff/Inputs/export.obj.yaml
@@ -48,4 +48,10 @@ symbols:
     SimpleType:      IMAGE_SYM_TYPE_NULL
     ComplexType:     IMAGE_SYM_DTYPE_NULL
     StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            _exportfn6
+    Value:           16
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
 ...
diff --git a/lld/test/pecoff/Inputs/exports.def b/lld/test/pecoff/Inputs/exports.def
index 54031a6f258a..360a58e64cb1 100644
--- a/lld/test/pecoff/Inputs/exports.def
+++ b/lld/test/pecoff/Inputs/exports.def
@@ -3,3 +3,4 @@
 EXPORTS
   exportfn1 @5   ; foo
   exportfn2
+  exportfn5=exportfn6
diff --git a/lld/test/pecoff/export.test b/lld/test/pecoff/export.test
index ed3a88a855ae..ebe5b1447aac 100644
--- a/lld/test/pecoff/export.test
+++ b/lld/test/pecoff/export.test
@@ -39,4 +39,5 @@ CHECK4:      DLL name: export.test.tmp4.dll
 CHECK4:       Ordinal      RVA  Name
 CHECK4-NEXT:        5   0x2008  exportfn1
 CHECK4-NEXT:        6   0x2010  exportfn2
-CHECK4-NEXT:        7   0x2010  exportfn3@256
+CHECK4-NEXT:        7   0x2010  exportfn6
+CHECK4-NEXT:        8   0x2010  exportfn3@256