[lld] r367673 - [COFF] Avoid loading objects for mingw autoimport, when a defined alias exists

[Martin Storsjo via llvm-commits]

Author: mstorsjo
Date: Fri Aug  2 04:02:34 2019
New Revision: 367673

URL: http://llvm.org/viewvc/llvm-project?rev=367673&view=rev
Log:
[COFF] Avoid loading objects for mingw autoimport, when a defined alias exists

This avoids a spurious and confusing log message in cases where
both e.g. "alias" and "__imp_alias" exist.

Differential Revision: https://reviews.llvm.org/D65598

Added:
    lld/trunk/test/COFF/Inputs/alias-implib.lib
    lld/trunk/test/COFF/alias-implib.s
Modified:
    lld/trunk/COFF/SymbolTable.cpp

Modified: lld/trunk/COFF/SymbolTable.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/SymbolTable.cpp?rev=367673&r1=367672&r2=367673&view=diff
==============================================================================
--- lld/trunk/COFF/SymbolTable.cpp (original)
+++ lld/trunk/COFF/SymbolTable.cpp Fri Aug  2 04:02:34 2019
@@ -185,6 +185,8 @@ void SymbolTable::loadMinGWAutomaticImpo
       continue;
     if (!sym->isUsedInRegularObj)
       continue;
+    if (undef->getWeakAlias())
+      continue;
 
     StringRef name = undef->getName();
 

Added: lld/trunk/test/COFF/Inputs/alias-implib.lib
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/Inputs/alias-implib.lib?rev=367673&view=auto
==============================================================================
Binary files lld/trunk/test/COFF/Inputs/alias-implib.lib (added) and lld/trunk/test/COFF/Inputs/alias-implib.lib Fri Aug  2 04:02:34 2019 differ

Added: lld/trunk/test/COFF/alias-implib.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/alias-implib.s?rev=367673&view=auto
==============================================================================
--- lld/trunk/test/COFF/alias-implib.s (added)
+++ lld/trunk/test/COFF/alias-implib.s Fri Aug  2 04:02:34 2019
@@ -0,0 +1,23 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-mingw32 -o %t.o %s
+# RUN: lld-link -lldmingw -entry:main -out:%t.exe %t.o %S/Inputs/alias-implib.lib -verbose 2>&1 | FileCheck %s
+
+# Check that the undefined (weak) alias symbol (with an existing lazy
+# __imp_alias) doesn't trigger trying to load __imp_alias for autoimport,
+# when the weak alias target actually does exist.
+
+# CHECK-NOT: Loading lazy{{.*}}for automatic import
+
+    .text
+    .globl main
+main:
+    call alias
+    ret
+
+# alias-implib.lib was created with "llvm-dlltool -m i386:x86-64
+# -l alias-implib.lib -d alias-implib.def" with this def snippet:
+# LIBRARY lib.dll
+# EXPORTS
+# realfunc
+# alias == realfunc