COFF: Fix /export.

Mangled dllexported symbols may be defined in a library.
If that's the case, we have to read a member file from the library.

llvm-svn: 240947

lld/COFF/SymbolTable.cpp

@@ -209,6 +209,10 @@ std::pair<StringRef, Symbol *> SymbolTable::findMangled(StringRef S) {
     Symbol *Sym = I.second;
     if (!Name.startswith(Prefix))
       continue;
+    if (auto *B = dyn_cast<Lazy>(Sym->Body)) {
+      addMemberFile(B);
+      run();
+    }
     if (isa<Defined>(Sym->Body))
       return std::make_pair(Name, Sym);
   }

lld/test/COFF/Inputs/export2.yaml

@@ -0,0 +1,29 @@
+---
+header:
+  Machine:         IMAGE_FILE_MACHINE_AMD64
+  Characteristics: []
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     B800000000506800000000680000000050E80000000050E800000000
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          28
+      NumberOfRelocations: 4
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          0
+  - Name:            '?mangled2@@YAHXZ'
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+...

lld/test/COFF/dll.test

@@ -14,6 +14,19 @@ EXPORT-NEXT:       2   0x1010  exportfn2
 EXPORT-NEXT:       3   0x1010  exportfn3
 EXPORT-NEXT:       4   0x1010  mangled
 
+# RUN: yaml2obj < %p/Inputs/export2.yaml > %t5.obj
+# RUN: rm -f %t5.lib
+# RUN: llvm-ar cru %t5.lib %t5.obj
+# RUN: lld -flavor link2 /out:%t5.dll /dll %t.obj %t5.lib /export:mangled2
+# RUN: llvm-objdump -p %t5.dll | FileCheck -check-prefix=EXPORT2 %s
+
+EXPORT2:      Export Table:
+EXPORT2:      DLL name: dll.test.tmp5.dll
+EXPORT2:      Ordinal      RVA  Name
+EXPORT2-NEXT:       0        0
+EXPORT2-NEXT:       1   0x1010  exportfn3
+EXPORT2-NEXT:       2   0x101c  mangled2
+
 # RUN: llvm-as -o %t.lto.obj %p/Inputs/export.ll
 # RUN: lld -flavor link2 /out:%t.lto.dll /dll %t.lto.obj /export:exportfn1 /export:exportfn2
 # RUN: llvm-objdump -p %t.lto.dll | FileCheck -check-prefix=EXPORT-LTO %s