[PATCH] D36065: [llvm-dlltool] Write correct weak externals

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo created this revision.
Herald added subscribers: inglorion, mehdi_amini.

Previously, the created object files for the import library were broken. Write the symbol table before the string table. Simplify the code by using a separate variable Prefix instead of duplicating a few lines.

Also update the coff-weak-exports to actually check that the generated weak symbols can be found as intended.


https://reviews.llvm.org/D36065

Files:
  lib/Object/COFFImportFile.cpp
  test/DllTool/coff-weak-exports.def


Index: test/DllTool/coff-weak-exports.def
===================================================================
--- test/DllTool/coff-weak-exports.def
+++ test/DllTool/coff-weak-exports.def
@@ -1,19 +1,11 @@
 ; RUN: llvm-dlltool -m i386:x86-64 --input-def %s --output-lib %t.a
-; RUN: llvm-readobj -coff-exports %t.a | FileCheck %s
+; RUN: llvm-nm %t.a | FileCheck %s
 
 LIBRARY test.dll
 EXPORTS
 TestFunction==AltTestFunction
 
-; CHECK: File: test.dll
-; CHECK: Format: COFF-x86-64
-; CHECK: Arch: x86_64
-; CHECK: AddressSize: 64bit
-; CHECK: File: test.dll
-; CHECK: Format: COFF-x86-64
-; CHECK: Arch: x86_64
-; CHECK: AddressSize: 64bit
-; CHECK: File: test.dll
-; CHECK: Format: COFF-x86-64
-; CHECK: Arch: x86_64
-; CHECK: AddressSize: 64bit
+; CHECK:      U AltTestFunction
+; CHECK-NEXT: w TestFunction
+; CHECK:      U __imp_AltTestFunction
+; CHECK-NEXT: w __imp_TestFunction
Index: lib/Object/COFFImportFile.cpp
===================================================================
--- lib/Object/COFFImportFile.cpp
+++ lib/Object/COFFImportFile.cpp
@@ -545,15 +545,11 @@
   SymbolTable[2].Name.Offset.Offset = sizeof(uint32_t);
 
   //__imp_ String Table
-  if (Imp) {
-    SymbolTable[3].Name.Offset.Offset = sizeof(uint32_t) + Sym.size() + 7;
-    writeStringTable(Buffer, {std::string("__imp_").append(Sym),
-                              std::string("__imp_").append(Weak)});
-  } else {
-    SymbolTable[3].Name.Offset.Offset = sizeof(uint32_t) + Sym.size() + 1;
-    writeStringTable(Buffer, {Sym, Weak});
-  }
+  StringRef Prefix = Imp ? "__imp_" : "";
+  SymbolTable[3].Name.Offset.Offset = sizeof(uint32_t) + Sym.size() + Prefix.size() + 1;
   append(Buffer, SymbolTable);
+  writeStringTable(Buffer, {Prefix.str().append(Sym),
+                            Prefix.str().append(Weak)});
 
   // Copied here so we can still use writeStringTable
   char *Buf = Alloc.Allocate<char>(Buffer.size());


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