[llvm] r210215 - Don't emit structors for available_externally globals (PR19933)

Hans Wennborg hans at hanshq.net
Wed Jun 4 14:04:54 PDT 2014


Author: hans
Date: Wed Jun  4 16:04:54 2014
New Revision: 210215

URL: http://llvm.org/viewvc/llvm-project?rev=210215&view=rev
Log:
Don't emit structors for available_externally globals (PR19933)

We would previously assert here when trying to figure out the section
for the global.

This makes us handle the situation more gracefully since the IR isn't
malformed.

Differential Revision: http://reviews.llvm.org/D4022

Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
    llvm/trunk/test/MC/COFF/global_ctors_dtors.ll

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp?rev=210215&r1=210214&r2=210215&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp Wed Jun  4 16:04:54 2014
@@ -1349,9 +1349,14 @@ void AsmPrinter::EmitXXStructorList(cons
     const TargetLoweringObjectFile &Obj = getObjFileLowering();
     const MCSymbol *KeySym = nullptr;
     const MCSection *KeySec = nullptr;
-    if (S.ComdatKey) {
-      KeySym = getSymbol(S.ComdatKey);
-      KeySec = getObjFileLowering().SectionForGlobal(S.ComdatKey, *Mang, TM);
+    if (GlobalValue *GV = S.ComdatKey) {
+      if (GV->hasAvailableExternallyLinkage())
+        // If the associated variable is available_externally, some other TU
+        // will provide its dynamic initializer.
+        continue;
+
+      KeySym = getSymbol(GV);
+      KeySec = getObjFileLowering().SectionForGlobal(GV, *Mang, TM);
     }
     const MCSection *OutputSection =
         (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym, KeySec)

Modified: llvm/trunk/test/MC/COFF/global_ctors_dtors.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/COFF/global_ctors_dtors.ll?rev=210215&r1=210214&r2=210215&view=diff
==============================================================================
--- llvm/trunk/test/MC/COFF/global_ctors_dtors.ll (original)
+++ llvm/trunk/test/MC/COFF/global_ctors_dtors.ll Wed Jun  4 16:04:54 2014
@@ -11,9 +11,10 @@
 
 %ini = type { i32, void()*, i8* }
 
- at llvm.global_ctors = appending global [2 x %ini ] [
+ at llvm.global_ctors = appending global [3 x %ini ] [
   %ini { i32 65535, void ()* @a_global_ctor, i8* null },
-  %ini { i32 65535, void ()* @b_global_ctor, i8* bitcast (i32* @b to i8*) }
+  %ini { i32 65535, void ()* @b_global_ctor, i8* bitcast (i32* @b to i8*) },
+  %ini { i32 65535, void ()* @c_global_ctor, i8* bitcast (i32* @c to i8*) }
 ]
 @llvm.global_dtors = appending global [1 x %ini ] [%ini { i32 65535, void ()* @a_global_dtor, i8* null }]
 
@@ -26,11 +27,18 @@ define void @a_global_ctor() nounwind {
 
 @b = global i32 zeroinitializer
 
+ at c = available_externally dllimport global i32 zeroinitializer
+
 define void @b_global_ctor() nounwind {
   store i32 42, i32* @b
   ret void
 }
 
+define void @c_global_ctor() nounwind {
+  store i32 42, i32* @c
+  ret void
+}
+
 define void @a_global_dtor() nounwind {
   %1 = call i32 @puts(i8* getelementptr inbounds ([12 x i8]* @.str2, i32 0, i32 0))
   ret void
@@ -45,11 +53,13 @@ define i32 @main() nounwind {
 ; WIN32: a_global_ctor
 ; WIN32: .section .CRT$XCU,"rd",associative .bss,{{_?}}b
 ; WIN32: b_global_ctor
+; WIN32-NOT: c_global_ctor
 ; WIN32: .section .CRT$XTX,"rd"
 ; WIN32: a_global_dtor
 ; MINGW32: .section .ctors,"wd"
 ; MINGW32: a_global_ctor
 ; MINGW32: .section .ctors,"wd",associative .bss,{{_?}}b
 ; MINGW32: b_global_ctor
+; MINGW32-NOT: c_global_ctor
 ; MINGW32: .section .dtors,"wd"
 ; MINGW32: a_global_dtor





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