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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196876 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 16 insertions, 9 deletions

diff --git a/include/llvm/CodeGen/MachineFrameInfo.h b/include/llvm/CodeGen/MachineFrameInfo.h
index 022634df87..747938f3f9 100644
--- a/include/llvm/CodeGen/MachineFrameInfo.h
+++ b/include/llvm/CodeGen/MachineFrameInfo.h
@@ -223,6 +223,10 @@ class MachineFrameInfo {
   /// Whether the "realign-stack" option is on.
   bool RealignOption;
 
+  /// True if the function includes inline assembly that adjusts the stack
+  /// pointer.
+  bool HasInlineAsmWithSPAdjust;
+
   const TargetFrameLowering *getFrameLowering() const;
 public:
     explicit MachineFrameInfo(const TargetMachine &TM, bool RealignOpt)
@@ -451,6 +455,10 @@ public:
   bool hasCalls() const { return HasCalls; }
   void setHasCalls(bool V) { HasCalls = V; }
 
+  /// Returns true if the function contains any stack-adjusting inline assembly.
+  bool hasInlineAsmWithSPAdjust() const { return HasInlineAsmWithSPAdjust; }
+  void setHasInlineAsmWithSPAdjust(bool B) { HasInlineAsmWithSPAdjust = B; }
+
   /// getMaxCallFrameSize - Return the maximum size of a call frame that must be
   /// allocated for an outgoing function call.  This is only available if
   /// CallFrameSetup/Destroy pseudo instructions are used by the target, and
diff --git a/include/llvm/CodeGen/MachineFunction.h b/include/llvm/CodeGen/MachineFunction.h
index c886e256e0..43b370cccf 100644
--- a/include/llvm/CodeGen/MachineFunction.h
+++ b/include/llvm/CodeGen/MachineFunction.h
@@ -131,8 +131,8 @@ class MachineFunction {
   /// about the control flow of such functions.
   bool ExposesReturnsTwice;
 
-  /// True if the function includes MS-style inline assembly.
-  bool HasMSInlineAsm;
+  /// True if the function includes any inline assembly.
+  bool HasInlineAsm;
 
   MachineFunction(const MachineFunction &) LLVM_DELETED_FUNCTION;
   void operator=(const MachineFunction&) LLVM_DELETED_FUNCTION;
@@ -218,15 +218,14 @@ public:
     ExposesReturnsTwice = B;
   }
 
-  /// Returns true if the function contains any MS-style inline assembly.
-  bool hasMSInlineAsm() const {
-    return HasMSInlineAsm;
+  /// Returns true if the function contains any inline assembly.
+  bool hasInlineAsm() const {
+    return HasInlineAsm;
   }
 
-  /// Set a flag that indicates that the function contains MS-style inline
-  /// assembly.
-  void setHasMSInlineAsm(bool B) {
-    HasMSInlineAsm = B;
+  /// Set a flag that indicates that the function contains inline assembly.
+  void setHasInlineAsm(bool B) {
+    HasInlineAsm = B;
   }
   
   /// getInfo - Keep track of various per-function pieces of information for