Add extra operand to CALLSEQ_START to keep frame part set up previously

Using arguments with attribute inalloca creates problems for verification
of machine representation. This attribute instructs the backend that the
argument is prepared in stack prior to  CALLSEQ_START..CALLSEQ_END
sequence (see http://llvm.org/docs/InAlloca.htm for details). Frame size
stored in CALLSEQ_START in this case does not count the size of this
argument. However CALLSEQ_END still keeps total frame size, as caller can
be responsible for cleanup of entire frame. So CALLSEQ_START and
CALLSEQ_END keep different frame size and the difference is treated by
MachineVerifier as stack error. Currently there is no way to distinguish
this case from actual errors.

This patch adds additional argument to CALLSEQ_START and its
target-specific counterparts to keep size of stack that is set up prior to
the call frame sequence. This argument allows MachineVerifier to calculate
actual frame size associated with frame setup instruction and correctly
process the case of inalloca arguments.

The changes made by the patch are:
- Frame setup instructions get the second mandatory argument. It
  affects all targets that use frame pseudo instructions and touched many
  files although the changes are uniform.
- Access to frame properties are implemented using special instructions
  rather than calls getOperand(N).getImm(). For X86 and ARM such
  replacement was made previously.
- Changes that reflect appearance of additional argument of frame setup
  instruction. These involve proper instruction initialization and
  methods that access instruction arguments.
- MachineVerifier retrieves frame size using method, which reports sum of
  frame parts initialized inside frame instruction pair and outside it.

The patch implements approach proposed by Quentin Colombet in
https://bugs.llvm.org/show_bug.cgi?id=27481#c1.
It fixes 9 tests failed with machine verifier enabled and listed
in PR27481.

Differential Revision: https://reviews.llvm.org/D32394

llvm-svn: 302527

4 files changed, 28 insertions, 6 deletions

diff --git a/llvm/include/llvm/CodeGen/ISDOpcodes.h b/llvm/include/llvm/CodeGen/ISDOpcodes.h
index 2bc218f0aec..f2a9a9f73ca 100644
--- a/llvm/include/llvm/CodeGen/ISDOpcodes.h
+++ b/llvm/include/llvm/CodeGen/ISDOpcodes.h
@@ -644,6 +644,13 @@ namespace ISD {
     /// of a call sequence, and carry arbitrary information that target might
     /// want to know.  The first operand is a chain, the rest are specified by
     /// the target and not touched by the DAG optimizers.
+    /// Targets that may use stack to pass call arguments define additional
+    /// operands:
+    /// - size of the call frame part that must be set up within the
+    ///   CALLSEQ_START..CALLSEQ_END pair,
+    /// - part of the call frame prepared prior to CALLSEQ_START.
+    /// Both these parameters must be constants, their sum is the total call
+    /// frame size.
     /// CALLSEQ_START..CALLSEQ_END pairs may not be nested.
     CALLSEQ_START,  // Beginning of a call sequence
     CALLSEQ_END,    // End of a call sequence
diff --git a/llvm/include/llvm/CodeGen/SelectionDAG.h b/llvm/include/llvm/CodeGen/SelectionDAG.h
index 9e1d148c7ce..0fcae262ee3 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAG.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAG.h
@@ -737,11 +737,15 @@ public:
   /// \brief Create a logical NOT operation as (XOR Val, BooleanOne).
   SDValue getLogicalNOT(const SDLoc &DL, SDValue Val, EVT VT);
 
-  /// Return a new CALLSEQ_START node, which always must have a glue result
-  /// (to ensure it's not CSE'd).  CALLSEQ_START does not have a useful SDLoc.
-  SDValue getCALLSEQ_START(SDValue Chain, SDValue Op, const SDLoc &DL) {
+  /// Return a new CALLSEQ_START node, that starts new call frame, in which
+  /// InSize bytes are set up inside CALLSEQ_START..CALLSEQ_END sequence and
+  /// OutSize specifies part of the frame set up prior to the sequence.
+  SDValue getCALLSEQ_START(SDValue Chain, uint64_t InSize, uint64_t OutSize,
+                           const SDLoc &DL) {
     SDVTList VTs = getVTList(MVT::Other, MVT::Glue);
-    SDValue Ops[] = { Chain,  Op };
+    SDValue Ops[] = { Chain,
+                      getIntPtrConstant(InSize, DL, true),
+                      getIntPtrConstant(OutSize, DL, true) };
     return getNode(ISD::CALLSEQ_START, DL, VTs, Ops);
   }
 
diff --git a/llvm/include/llvm/Target/TargetInstrInfo.h b/llvm/include/llvm/Target/TargetInstrInfo.h
index 82a682cf1f7..97a6f0c6e3a 100644
--- a/llvm/include/llvm/Target/TargetInstrInfo.h
+++ b/llvm/include/llvm/Target/TargetInstrInfo.h
@@ -172,11 +172,22 @@ public:
   /// inalloca arguments. This function reports only the size of the frame part
   /// that is set up between the frame setup and destroy pseudo instructions.
   int64_t getFrameSize(const MachineInstr &I) const {
-    assert(isFrameInstr(I));
+    assert(isFrameInstr(I) && "Not a frame instruction");
     assert(I.getOperand(0).getImm() >= 0);
     return I.getOperand(0).getImm();
   }
 
+  /// Returns the total frame size, which is made up of the space set up inside
+  /// the pair of frame start-stop instructions and the space that is set up
+  /// prior to the pair.
+  int64_t getFrameTotalSize(const MachineInstr &I) const {
+    if (isFrameSetup(I)) {
+      assert(I.getOperand(1).getImm() >= 0 && "Frame size must not be negative");
+      return getFrameSize(I) + I.getOperand(1).getImm();
+    }
+    return getFrameSize(I);
+  }
+
   unsigned getCatchReturnOpcode() const { return CatchRetOpcode; }
   unsigned getReturnOpcode() const { return ReturnOpcode; }
 
diff --git a/llvm/include/llvm/Target/TargetSelectionDAG.td b/llvm/include/llvm/Target/TargetSelectionDAG.td
index 45a842f77a2..9ed614ccee1 100644
--- a/llvm/include/llvm/Target/TargetSelectionDAG.td
+++ b/llvm/include/llvm/Target/TargetSelectionDAG.td
@@ -281,7 +281,7 @@ def SDTConvertOp : SDTypeProfile<1, 5, [ //cvtss, su, us, uu, ff, fs, fu, sf, su
 ]>;
 
 class SDCallSeqStart<list<SDTypeConstraint> constraints> :
-        SDTypeProfile<0, 1, constraints>;
+        SDTypeProfile<0, 2, constraints>;
 class SDCallSeqEnd<list<SDTypeConstraint> constraints> :
         SDTypeProfile<0, 2, constraints>;