[lld] [COFF] Don't produce weak aliases in import libraries

[mstorsjo]

Summary

When creating an import library from lld, the cases with Name != ExtName shouldn't end up as a weak alias, but as a real export of the new name, which is what actually is exported from the DLL.

This restores the behaviour of renamed exports to what it was in 4.0 - this is a regression since the introduction of llvm-dlltool.

[rnk]

lgtm

[mstorsjo]

Just FWIW, I was about to commit this, but noticed that this test actually depends on D36545, which depends on D36544 (which is yet unapproved). So I'll need to hold off of this one until those patches are merged first.

lld/trunk/COFF/Driver.cpp

for (Export &E1 : Config->Exports) {
     E2.Noname = E1.Noname;
     E2.Data = E1.Data;
     E2.Private = E1.Private;
     E2.Constant = E1.Constant;
     Exports.push_back(E2);
   }
 
   writeImportLibrary(getImportName(AsLib), getImplibPath(), Exports,
-                     Config->Machine);
+                     Config->Machine, false);
 }
 
 static void parseModuleDefs(StringRef Path) {
   std::unique_ptr<MemoryBuffer> MB = check(
     MemoryBuffer::getFile(Path, -1, false, true), "could not open " + Path);
   COFFModuleDefinition M =
       check(parseCOFFModuleDefinition(MB->getMemBufferRef(), Config->Machine));
 

lld/trunk/test/COFF/export.test

 CHECK3-NEXT:       0        0
 CHECK3-NEXT:       1        0
 CHECK3-NEXT:       2        0
 CHECK3-NEXT:       3        0
 CHECK3-NEXT:       4        0
 CHECK3-NEXT:       5   0x1008
 CHECK3-NEXT:       6   0x1010  exportfn2
 
-# RUN: lld-link /out:%t.dll /dll %t.obj /export:f1=exportfn1 /export:f2=exportfn2
+# RUN: lld-link /out:%t.dll /dll %t.obj /export:f1=exportfn1 /export:f2=exportfn2 /implib:%t.lib
 # RUN: llvm-objdump -p %t.dll | FileCheck -check-prefix=CHECK4 %s
+# RUN: llvm-nm %t.lib | FileCheck -check-prefix=CHECK4-NM %s
 
 CHECK4:      Export Table:
 CHECK4:      DLL name: export.test.tmp.dll
 CHECK4:      Ordinal      RVA  Name
 CHECK4-NEXT:       0        0
 CHECK4-NEXT:       1   0x1010  exportfn3
 CHECK4-NEXT:       2   0x1008  f1
 CHECK4-NEXT:       3   0x1010  f2
+CHECK4-NM: 00000000 T f1
+CHECK4-NM: 00000000 T f2
 
 # RUN: echo "EXPORTS exportfn1 @3" > %t.def
 # RUN: echo "fn2=exportfn2 @2" >> %t.def
 # RUN: lld-link /out:%t.dll /dll %t.obj /def:%t.def
 # RUN: llvm-objdump -p %t.dll | FileCheck -check-prefix=CHECK5 %s
 
 CHECK5:      Export Table:
 CHECK5:      DLL name: export.test.tmp.dll