Fix miscompile of MS inline assembly with stack realignment

For stack frames requiring realignment, three pointers may be needed:
- ebp to address incoming arguments
- esi (could be any callee-saved register) to address locals
- esp to address outgoing arguments

We would use esi unconditionally without verifying that it did not
conflict with inline assembly.

This change doesn't do the verification, it simply emits a fatal error
on functions that use stack realignment, dynamic SP adjustments, and
inline assembly.

Because stack realignment is common on Windows, we also no longer assume
that MS inline assembly clobbers esp.  Instead, we analyze the inline
instructions for implicit definitions and check if esp is there.  If so,
we require the use of a base pointer and consider it in the condition
above.

Mostly fixes PR16830, but we could try harder to find a non-conflicting
base pointer.

Reviewers: sunfish

Differential Revision: http://llvm-reviews.chandlerc.com/D1317

llvm-svn: 196876

1 files changed, 6 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 6c335d96c73..506b7380515 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -428,7 +428,9 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
 
   SDB->init(GFI, *AA, LibInfo);
 
-  MF->setHasMSInlineAsm(false);
+  MF->setHasInlineAsm(false);
+  MF->getFrameInfo()->setHasInlineAsmWithSPAdjust(false);
+
   SelectAllBasicBlocks(Fn);
 
   // If the first basic block in the function has live ins that need to be
@@ -512,7 +514,7 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
   for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E;
        ++I) {
 
-    if (MFI->hasCalls() && MF->hasMSInlineAsm())
+    if (MFI->hasCalls() && MF->hasInlineAsm())
       break;
 
     const MachineBasicBlock *MBB = I;
@@ -523,8 +525,8 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
           II->isStackAligningInlineAsm()) {
         MFI->setHasCalls(true);
       }
-      if (II->isMSInlineAsm()) {
-        MF->setHasMSInlineAsm(true);
+      if (II->isInlineAsm()) {
+        MF->setHasInlineAsm(true);
       }
     }
   }