From eb11fae6d08f479c0799db45860a98af528fa6e7 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Sat, 28 Jul 2018 10:51:19 +0000
Subject: Vendor import of llvm trunk r338150:
 https://llvm.org/svn/llvm-project/llvm/trunk@338150

---
 lib/Object/COFFImportFile.cpp | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

(limited to 'lib/Object/COFFImportFile.cpp')

diff --git a/lib/Object/COFFImportFile.cpp b/lib/Object/COFFImportFile.cpp
index 93631f1ad811..dc11cc4bcffe 100644
--- a/lib/Object/COFFImportFile.cpp
+++ b/lib/Object/COFFImportFile.cpp
@@ -91,7 +91,15 @@ static void writeStringTable(std::vector<uint8_t> &B,
 }
 
 static ImportNameType getNameType(StringRef Sym, StringRef ExtName,
-                                  MachineTypes Machine) {
+                                  MachineTypes Machine, bool MinGW) {
+  // A decorated stdcall function in MSVC is exported with the
+  // type IMPORT_NAME, and the exported function name includes the
+  // the leading underscore. In MinGW on the other hand, a decorated
+  // stdcall function still omits the underscore (IMPORT_NAME_NOPREFIX).
+  // See the comment in isDecorated in COFFModuleDefinition.cpp for more
+  // details.
+  if (ExtName.startswith("_") && ExtName.contains('@') && !MinGW)
+    return IMPORT_NAME;
   if (Sym != ExtName)
     return IMPORT_NAME_UNDECORATE;
   if (Machine == IMAGE_FILE_MACHINE_I386 && Sym.startswith("_"))
@@ -538,7 +546,12 @@ NewArchiveMember ObjectFactory::createWeakExternal(StringRef Sym,
        u16(0),
        IMAGE_SYM_CLASS_WEAK_EXTERNAL,
        1},
-      {{{2, 0, 0, 0, 3, 0, 0, 0}}, u32(0), u16(0), u16(0), uint8_t(0), 0},
+      {{{2, 0, 0, 0, IMAGE_WEAK_EXTERN_SEARCH_ALIAS, 0, 0, 0}},
+       u32(0),
+       u16(0),
+       u16(0),
+       IMAGE_SYM_CLASS_NULL,
+       0},
   };
   SymbolTable[2].Name.Offset.Offset = sizeof(uint32_t);
 
@@ -558,7 +571,7 @@ NewArchiveMember ObjectFactory::createWeakExternal(StringRef Sym,
 
 Error writeImportLibrary(StringRef ImportName, StringRef Path,
                          ArrayRef<COFFShortExport> Exports,
-                         MachineTypes Machine, bool MakeWeakAliases) {
+                         MachineTypes Machine, bool MinGW) {
 
   std::vector<NewArchiveMember> Members;
   ObjectFactory OF(llvm::sys::path::filename(ImportName), Machine);
@@ -576,12 +589,6 @@ Error writeImportLibrary(StringRef ImportName, StringRef Path,
     if (E.Private)
       continue;
 
-    if (E.isWeak() && MakeWeakAliases) {
-      Members.push_back(OF.createWeakExternal(E.Name, E.ExtName, false));
-      Members.push_back(OF.createWeakExternal(E.Name, E.ExtName, true));
-      continue;
-    }
-
     ImportType ImportType = IMPORT_CODE;
     if (E.Data)
       ImportType = IMPORT_DATA;
@@ -589,7 +596,7 @@ Error writeImportLibrary(StringRef ImportName, StringRef Path,
       ImportType = IMPORT_CONST;
 
     StringRef SymbolName = E.SymbolName.empty() ? E.Name : E.SymbolName;
-    ImportNameType NameType = getNameType(SymbolName, E.Name, Machine);
+    ImportNameType NameType = getNameType(SymbolName, E.Name, Machine, MinGW);
     Expected<std::string> Name = E.ExtName.empty()
                                      ? SymbolName
                                      : replace(SymbolName, E.Name, E.ExtName);
@@ -597,6 +604,12 @@ Error writeImportLibrary(StringRef ImportName, StringRef Path,
     if (!Name)
       return Name.takeError();
 
+    if (!E.AliasTarget.empty() && *Name != E.AliasTarget) {
+      Members.push_back(OF.createWeakExternal(E.AliasTarget, *Name, false));
+      Members.push_back(OF.createWeakExternal(E.AliasTarget, *Name, true));
+      continue;
+    }
+
     Members.push_back(
         OF.createShortImport(*Name, E.Ordinal, ImportType, NameType));
   }
-- 
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