[llvm-commits] [llvm] r141859 - in /llvm/trunk: lib/Target/X86/X86FrameLowering.cpp test/CodeGen/X86/segmented-stacks.ll

[Bill Wendling]

Author: void
Date: Thu Oct 13 03:24:19 2011
New Revision: 141859

URL: http://llvm.org/viewvc/llvm-project?rev=141859&view=rev
Log:
More closely follow libgcc, which has code after the `ret' instruction to
release the stack segment and reset the stack pointer. Place the code in its own
MBB to make the verifier happy.

Modified:
    llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
    llvm/trunk/test/CodeGen/X86/segmented-stacks.ll

Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.cpp?rev=141859&r1=141858&r2=141859&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86FrameLowering.cpp Thu Oct 13 03:24:19 2011
@@ -1336,15 +1336,28 @@
   if (Is64Bit)
     IsNested = HasNestArgument(&MF);
 
+  // The MOV R10, RAX needs to be in a different block, since the RET we emit in
+  // allocMBB needs to be last (terminating) instruction.
+  MachineBasicBlock *restoreR10MBB = NULL;
+  if (IsNested)
+    restoreR10MBB = MF.CreateMachineBasicBlock();
+
   for (MachineBasicBlock::livein_iterator i = prologueMBB.livein_begin(),
          e = prologueMBB.livein_end(); i != e; i++) {
     allocMBB->addLiveIn(*i);
     checkMBB->addLiveIn(*i);
+
+    if (IsNested)
+      restoreR10MBB->addLiveIn(*i);
   }
 
-  if (IsNested)
+  if (IsNested) {
     allocMBB->addLiveIn(X86::R10);
+    restoreR10MBB->addLiveIn(X86::RAX);
+  }
 
+  if (IsNested)
+    MF.push_front(restoreR10MBB);
   MF.push_front(allocMBB);
   MF.push_front(checkMBB);
 
@@ -1414,13 +1427,19 @@
   if (!Is64Bit)
     BuildMI(allocMBB, DL, TII.get(X86::ADD32ri), X86::ESP).addReg(X86::ESP)
       .addImm(8);
+  BuildMI(allocMBB, DL, TII.get(X86::RET));
 
-  if (Is64Bit && IsNested)
-    BuildMI(allocMBB, DL, TII.get(X86::MOV64rr), X86::R10).addReg(X86::RAX);
+  if (IsNested)
+    BuildMI(restoreR10MBB, DL, TII.get(X86::MOV64rr), X86::R10)
+      .addReg(X86::RAX);
 
-  BuildMI(allocMBB, DL, TII.get(X86::RET));
+  if (IsNested) {
+    allocMBB->addSuccessor(restoreR10MBB);
+    restoreR10MBB->addSuccessor(&prologueMBB);
+  } else {
+    allocMBB->addSuccessor(&prologueMBB);
+  }
 
-  allocMBB->addSuccessor(&prologueMBB);
   checkMBB->addSuccessor(allocMBB);
   checkMBB->addSuccessor(&prologueMBB);
 

Modified: llvm/trunk/test/CodeGen/X86/segmented-stacks.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/segmented-stacks.ll?rev=141859&r1=141858&r2=141859&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/segmented-stacks.ll (original)
+++ llvm/trunk/test/CodeGen/X86/segmented-stacks.ll Thu Oct 13 03:24:19 2011
@@ -81,7 +81,7 @@
 ; X64-NEXT: movabsq $0, %r10
 ; X64-NEXT: movabsq $0, %r11
 ; X64-NEXT: callq __morestack
-; X64-NEXT: movq %rax, %r10
 ; X64-NEXT: ret
+; X64:      movq %rax, %r10
 
 }