Index: flang/include/flang/Tools/CLOptions.inc
===================================================================
--- flang/include/flang/Tools/CLOptions.inc
+++ flang/include/flang/Tools/CLOptions.inc
@@ -164,6 +164,7 @@
   pm.addNestedPass<mlir::FuncOp>(fir::createAbstractResultOptPass());
   fir::addCodeGenRewritePass(pm);
   fir::addTargetRewritePass(pm);
+  pm.addPass(fir::createExternalNameConversionPass());
   fir::addFIRToLLVMPass(pm);
 }
 
Index: flang/test/Lower/common-block.f90
===================================================================
--- flang/test/Lower/common-block.f90
+++ flang/test/Lower/common-block.f90
@@ -1,40 +1,40 @@
 ! RUN: bbc %s -o - | tco | FileCheck %s
 
-! CHECK: @_QB = common global [8 x i8] zeroinitializer
-! CHECK: @_QBx = global { float, float } { float 1.0{{.*}}, float 2.0{{.*}} }
-! CHECK: @_QBy = common global [12 x i8] zeroinitializer
-! CHECK: @_QBz = global { i32, [4 x i8], float } { i32 42, [4 x i8] undef, float 3.000000e+00 }
-! CHECK: @_QBrien = common global [1 x i8] zeroinitializer
-! CHECK: @_QBwith_empty_equiv = common global [8 x i8] zeroinitializer
+! CHECK: @__BLNK__ = common global [8 x i8] zeroinitializer
+! CHECK: @x_ = global { float, float } { float 1.0{{.*}}, float 2.0{{.*}} }
+! CHECK: @y_ = common global [12 x i8] zeroinitializer
+! CHECK: @z_ = global { i32, [4 x i8], float } { i32 42, [4 x i8] undef, float 3.000000e+00 }
+! CHECK: @rien_ = common global [1 x i8] zeroinitializer
+! CHECK: @with_empty_equiv_ = common global [8 x i8] zeroinitializer
 
-! CHECK-LABEL: _QPs0
+! CHECK-LABEL: s0_
 subroutine s0
     common // a0, b0
   
-    ! CHECK: call void @_QPs(float* bitcast ([8 x i8]* @_QB to float*), float* bitcast (i8* getelementptr inbounds ([8 x i8], [8 x i8]* @_QB, i32 0, i64 4) to float*))
+    ! CHECK: call void @s_(float* bitcast ([8 x i8]* @__BLNK__ to float*), float* bitcast (i8* getelementptr inbounds ([8 x i8], [8 x i8]* @__BLNK__, i32 0, i64 4) to float*))
     call s(a0, b0)
   end subroutine s0
   
-  ! CHECK-LABEL: _QPs1
+  ! CHECK-LABEL: s1_
   subroutine s1
     common /x/ a1, b1
     data a1 /1.0/, b1 /2.0/
   
-    ! CHECK: call void @_QPs(float* getelementptr inbounds ({ float, float }, { float, float }* @_QBx, i32 0, i32 0), float* bitcast (i8* getelementptr (i8, i8* bitcast ({ float, float }* @_QBx to i8*), i64 4) to float*))
+    ! CHECK: call void @s_(float* getelementptr inbounds ({ float, float }, { float, float }* @x_, i32 0, i32 0), float* bitcast (i8* getelementptr (i8, i8* bitcast ({ float, float }* @x_ to i8*), i64 4) to float*))
     call s(a1, b1)
   end subroutine s1
   
-  ! CHECK-LABEL: _QPs2
+  ! CHECK-LABEL: s2_
   subroutine s2
     common /y/ a2, b2, c2
   
-    ! CHECK: call void @_QPs(float* bitcast ([12 x i8]* @_QBy to float*), float* bitcast (i8* getelementptr inbounds ([12 x i8], [12 x i8]* @_QBy, i32 0, i64 4) to float*))
+    ! CHECK: call void @s_(float* bitcast ([12 x i8]* @y_ to float*), float* bitcast (i8* getelementptr inbounds ([12 x i8], [12 x i8]* @y_, i32 0, i64 4) to float*))
     call s(a2, b2)
   end subroutine s2
   
   ! Test that common initialized through aliases of common members are getting
   ! the correct initializer.
-  ! CHECK-LABEL: _QPs3
+  ! CHECK-LABEL: s3_
   subroutine s3
    integer :: i = 42
    real :: x
@@ -50,22 +50,22 @@
     integer :: i, j
     common /c_in_mod/ i, j
   end module
-  ! CHECK-LABEL: _QPs4
+  ! CHECK-LABEL: s4_
   subroutine s4
     use mod_with_common
-    ! CHECK: load i32, i32* bitcast ([8 x i8]* @_QBc_in_mod to i32*)
+    ! CHECK: load i32, i32* bitcast ([8 x i8]* @c_in_mod_ to i32*)
     print *, i
-    ! CHECK: load i32, i32* bitcast (i8* getelementptr inbounds ([8 x i8], [8 x i8]* @_QBc_in_mod, i32 0, i64 4) to i32*)
+    ! CHECK: load i32, i32* bitcast (i8* getelementptr inbounds ([8 x i8], [8 x i8]* @c_in_mod_, i32 0, i64 4) to i32*)
     print *, j
   end subroutine s4
   
-  ! CHECK-LABEL: _QPs5
+  ! CHECK-LABEL: s5_
   subroutine s5
     real r(1:0)
     common /rien/ r
   end subroutine s5
   
-  ! CHECK-LABEL: _QPs6
+  ! CHECK-LABEL: s6_
   subroutine s6
     real r1(1:0), r2(1:0), x, y
     common /with_empty_equiv/ x, r1, y