[gold] Fix linkInModule and extend common.ll test.

[eugenis]

Summary

Fix early exit from linkInModule. IRMover::move returns false on
success and true on error.

Add a few more cases of merged common linkage variables with different sizes and alignments.

[• rafael]

Lgtm

[eugenis]

Thanks.
This actually shows a bug in the plugin. I've added a fix to the same revision.

[eugenis]

r267437

test/tools/gold/X86/Inputs/common.ll

-@a = common global i16 0, align 4
+@a = common global i32 0, align 4

test/tools/gold/X86/Inputs/common2.ll

+@a = common global i8 0, align 16

test/tools/gold/X86/Inputs/common3.ll

+@a = common global i8 0, align 1

test/tools/gold/X86/common.ll

 ; RUN: llvm-as %s -o %t1.o
 ; RUN: llvm-as %p/Inputs/common.ll -o %t2.o
+; RUN: llvm-as %p/Inputs/common2.ll -o %t2b.o
+; RUN: llvm-as %p/Inputs/common3.ll -o %t2c.o
+
+@a = common global i16 0, align 8
 
 ; RUN: %gold -plugin %llvmshlibdir/LLVMgold.so \
 ; RUN:    --plugin-opt=emit-llvm \
 ; RUN:    -shared %t1.o %t2.o -o %t3.o
-; RUN: llvm-dis %t3.o -o - | FileCheck %s
-
-@a = common global i8 0, align 8
+; RUN: llvm-dis %t3.o -o - | FileCheck %s --check-prefix=A
 
 ; Shared library case, we merge @a as common and keep it for the symbol table.
-; CHECK: @a = common global i16 0, align 8
+; A: @a = common global i32 0, align 8
+
+; RUN: %gold -plugin %llvmshlibdir/LLVMgold.so \
+; RUN:    --plugin-opt=emit-llvm \
+; RUN:    -shared %t1.o %t2b.o -o %t3.o
+; RUN: llvm-dis %t3.o -o - | FileCheck %s --check-prefix=B
+
+; (i16 align 8) + (i8 align 16) = i16 align 16
+; B: @a = common global i16 0, align 16
+
+; RUN: %gold -plugin %llvmshlibdir/LLVMgold.so \
+; RUN:    --plugin-opt=emit-llvm \
+; RUN:    -shared %t1.o %t2c.o -o %t3.o
+; RUN: llvm-dis %t3.o -o - | FileCheck %s --check-prefix=C
+
+; (i16 align 8) + (i8 align 1) = i16 align 8.
+; C: @a = common global i16 0, align 8
 
 ; RUN: %gold -plugin %llvmshlibdir/LLVMgold.so \
 ; RUN:    --plugin-opt=emit-llvm \
 ; RUN:    %t1.o %t2.o -o %t3.o
 ; RUN: llvm-dis %t3.o -o - | FileCheck --check-prefix=EXEC %s
 
 ; All IR case, we internalize a after merging.
-; EXEC: @a = internal global i16 0, align 8
+; EXEC: @a = internal global i32 0, align 8
 
-; RUN: llc %p/Inputs/common.ll -o %t2.o -filetype=obj
+; RUN: llc %p/Inputs/common.ll -o %t2native.o -filetype=obj
 ; RUN: %gold -plugin %llvmshlibdir/LLVMgold.so \
 ; RUN:    --plugin-opt=emit-llvm \
-; RUN:    %t1.o %t2.o -o %t3.o
+; RUN:    %t1.o %t2native.o -o %t3.o
 ; RUN: llvm-dis %t3.o -o - | FileCheck --check-prefix=MIXED %s
 
 ; Mixed ELF and IR. We keep ours as common so the linker will finish the merge.
-; MIXED: @a = common global i8 0, align 8
+; MIXED: @a = common global i16 0, align 8

tools/gold/gold-plugin.cpp

static bool linkInModule(LLVMContext &Context, IRMover &L, claimed_file &F,
   if (!M.get())
     return false;
   if (!options::triple.empty())
     M->setTargetTriple(options::triple.c_str());
   else if (M->getTargetTriple().empty()) {
     M->setTargetTriple(DefaultTriple);
   }
 
-  if (!L.move(std::move(M), Keep, [](GlobalValue &, IRMover::ValueAdder) {}))
-    return false;
+  if (L.move(std::move(M), Keep, [](GlobalValue &, IRMover::ValueAdder) {}))
+    return true;
 
   for (const auto &I : Realign) {
     GlobalValue *Dst = L.getModule().getNamedValue(I.first());
     if (!Dst)
       continue;
     cast<GlobalVariable>(Dst)->setAlignment(I.second);
   }
 
-  return true;
+  return false;
 }
 
 /// Perform the ThinLTO backend on a single module, invoking the LTO and codegen
 /// pipelines.
 static void thinLTOBackendTask(claimed_file &F, const void *View,
                                ld_plugin_input_file &File,
                                raw_fd_ostream *ApiFile,
                                const ModuleSummaryIndex &CombinedIndex,