The address of an indirect call must be in R12 on Darwin.

Make it so.  (This patch is in LowerCall_Darwin, which seems
to be used by SVR4 code as well; since that doesn't belong here,
I haven't worried about this case.)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98077 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCISelLowering.cpp

@@ -3258,6 +3258,16 @@ PPCTargetLowering::LowerCall_Darwin(SDValue Chain, SDValue Callee,
                          false, false, 0);
   }
 
+  // On Darwin, R12 must contain the address of an indirect callee.  This does
+  // not mean the MTCTR instruction must use R12; it's easier to model this as
+  // an extra parameter, so do that.
+  if (!isTailCall && 
+      !dyn_cast<GlobalAddressSDNode>(Callee) &&
+      !dyn_cast<ExternalSymbolSDNode>(Callee) &&
+      !isBLACompatibleAddress(Callee, DAG))
+    RegsToPass.push_back(std::make_pair((unsigned)(isPPC64 ? PPC::X12 :
+                                                   PPC::R12), Callee));
+
   // Build a sequence of copy-to-reg nodes chained together with token chain
   // and flag operands which copy the outgoing args into the appropriate regs.
   SDValue InFlag;

test/CodeGen/PowerPC/2010-03-09-indirect-call.ll

@@ -0,0 +1,19 @@
+; RUN: llc < %s -march=ppc32 -mcpu=g5 -mtriple=powerpc-apple-darwin10.0 | FileCheck %s
+; ModuleID = 'nn.c'
+target datalayout = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f128:64:128"
+target triple = "powerpc-apple-darwin11.0"
+; Indirect calls must use R12 on Darwin (i.e., R12 must contain the address of
+; the function being called; the mtctr is not required to use it).
+
+@p = external global void (...)*                  ; <void (...)**> [#uses=1]
+
+define void @foo() nounwind ssp {
+entry:
+; CHECK: mtctr r12
+  %0 = load void (...)** @p, align 4              ; <void (...)*> [#uses=1]
+  call void (...)* %0() nounwind
+  br label %return
+
+return:                                           ; preds = %entry
+  ret void
+}