[PATCH] D111151: [CodeGen][Outliner] Fix CFICount calculations

[Alexander Shaposhnikov via Phabricator via llvm-commits]

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getFrameInstructions returns a vector cfi instructions in the function's prologue, not in the entire function, see e.g.
https://llvm.org/doxygen/MachineFunction_8h_source.html#l01006
This diff introduces a helper method getCFIInstructionCount and adjusts the calculations in X86InstrInfo / AArch64InstrInfo accordingly.

Test plan: make check-all


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D111151

Files:
  llvm/include/llvm/CodeGen/MachineFunction.h
  llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
  llvm/lib/Target/X86/X86InstrInfo.cpp


Index: llvm/lib/Target/X86/X86InstrInfo.cpp
===================================================================
--- llvm/lib/Target/X86/X86InstrInfo.cpp
+++ llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -9127,13 +9127,8 @@
   MachineBasicBlock::iterator MBBI = RepeatedSequenceLocs[0].front();
   for (unsigned Loc = RepeatedSequenceLocs[0].getStartIdx();
        Loc < RepeatedSequenceLocs[0].getEndIdx() + 1; Loc++) {
-    const std::vector<MCCFIInstruction> &CFIInstructions =
-        RepeatedSequenceLocs[0].getMF()->getFrameInstructions();
-    if (MBBI->isCFIInstruction()) {
-      unsigned CFIIndex = MBBI->getOperand(0).getCFIIndex();
-      MCCFIInstruction CFI = CFIInstructions[CFIIndex];
+    if (MBBI->isCFIInstruction())
       CFICount++;
-    }
     MBBI++;
   }
 
@@ -9142,13 +9137,11 @@
   // since if we outline one of the CFI instructions in a function, we have to
   // outline them all for correctness. If we do not, the address offsets will be
   // incorrect between the two sections of the program.
-  for (outliner::Candidate &C : RepeatedSequenceLocs) {
-    std::vector<MCCFIInstruction> CFIInstructions =
-        C.getMF()->getFrameInstructions();
-
-    if (CFICount > 0 && CFICount != CFIInstructions.size())
-      return outliner::OutlinedFunction();
-  }
+  if (CFICount > 0 &&
+      any_of(RepeatedSequenceLocs, [CFICount](const outliner::Candidate &C) {
+        return C.getMF()->getCFIInstructionCount() != CFICount;
+      }))
+    return outliner::OutlinedFunction();
 
   // FIXME: Use real size in bytes for call and ret instructions.
   if (RepeatedSequenceLocs[0].back()->isTerminator()) {
Index: llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -6573,13 +6573,8 @@
   MachineBasicBlock::iterator MBBI = RepeatedSequenceLocs[0].front();
   for (unsigned Loc = RepeatedSequenceLocs[0].getStartIdx();
        Loc < RepeatedSequenceLocs[0].getEndIdx() + 1; Loc++) {
-    const std::vector<MCCFIInstruction> &CFIInstructions =
-        RepeatedSequenceLocs[0].getMF()->getFrameInstructions();
-    if (MBBI->isCFIInstruction()) {
-      unsigned CFIIndex = MBBI->getOperand(0).getCFIIndex();
-      MCCFIInstruction CFI = CFIInstructions[CFIIndex];
+    if (MBBI->isCFIInstruction())
       CFICount++;
-    }
     MBBI++;
   }
 
@@ -6588,13 +6583,11 @@
   // since if we outline one of the CFI instructions in a function, we have to
   // outline them all for correctness. If we do not, the address offsets will be
   // incorrect between the two sections of the program.
-  for (outliner::Candidate &C : RepeatedSequenceLocs) {
-    std::vector<MCCFIInstruction> CFIInstructions =
-        C.getMF()->getFrameInstructions();
-
-    if (CFICount > 0 && CFICount != CFIInstructions.size())
-      return outliner::OutlinedFunction();
-  }
+  if (CFICount > 0 &&
+      any_of(RepeatedSequenceLocs, [CFICount](const outliner::Candidate &C) {
+        return C.getMF()->getCFIInstructionCount() != CFICount;
+      }))
+    return outliner::OutlinedFunction();
 
   // Returns true if an instructions is safe to fix up, false otherwise.
   auto IsSafeToFixup = [this, &TRI](MachineInstr &MI) {
Index: llvm/include/llvm/CodeGen/MachineFunction.h
===================================================================
--- llvm/include/llvm/CodeGen/MachineFunction.h
+++ llvm/include/llvm/CodeGen/MachineFunction.h
@@ -855,6 +855,16 @@
     return InstrCount;
   }
 
+  /// Return the number of CFI \p MachineInstrs in this \p MachineFunction.
+  unsigned getCFIInstructionCount() const {
+    unsigned CFIInstrCount = 0;
+    for (const MachineBasicBlock &MBB : BasicBlocks)
+      CFIInstrCount += count_if(MBB, [](const MachineInstr &MI) {
+        return MI.isCFIInstruction();
+      });
+    return CFIInstrCount;
+  }
+
   //===--------------------------------------------------------------------===//
   // Internal functions used to automatically number MachineBasicBlocks
 


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