[llvm][codegen] Fix non-determinism in StackFrameLayoutAnalysisPass output

[paulkirth]

Summary

We were iterating over a SmallPtrSet when outputting slot variables.
This is still correct but made the test fail under reverse iteration.
This patch replaces the SmallPtrSet with a SmallVector.

Also remove the "Stack Frame Layout" lines from arm64-opt-remarks-lazy-bfi test,
since those also break under reverse iteration.

[myhsu]

You can use llvm::SetVector if elements need to be unique

[paulkirth]

In D142127#4066030, @myhsu wrote:

You can use llvm::SetVector if elements need to be unique

That's a great suggestion. Thanks @myhsu

[paulkirth]

Switch to SetVector from SmallVector, since we'd like to ensure these are unique.

[paulkirth]

Remove checks added to arm test, since they break under reverse iteration.
The test now just ignores the lines related to Stack Frame Analaysis, which is probably a better choice anyway.

llvm/lib/CodeGen/StackFrameLayoutAnalysisPass.cpp

 // layout of the stack frame, using the remarks interface. On the CLI it prints
 // a textual representation of the stack frame. When possible it prints the
 // values that occupy a stack slot using any available debug information. Since
 // output is remarks based, it is also available in a machine readable file
 // format, such as YAML.
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/SetVector.h"
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/SlotIndexes.h"
 #include "llvm/CodeGen/StackProtector.h"

 #define DEBUG_TYPE "stack-frame-layout"
 
 namespace {
 
 /// StackFrameLayoutAnalysisPass - This is a pass to dump the stack frame of a
 /// MachineFunction.
 ///
 struct StackFrameLayoutAnalysisPass : public MachineFunctionPass {
-  using SlotDbgMap =
-      SmallDenseMap<int, SmallPtrSet<const DILocalVariable *, 4>>;
+  using SlotDbgMap = SmallDenseMap<int, SetVector<const DILocalVariable *>>;
   static char ID;
 
   enum SlotType {
     Spill,          // a Spill slot
     StackProtector, // Stack Protector slot
     Variable,       // a slot used to store a local data (could be a tmp)
     Invalid         // It's an error for a slot to have this type
   };
void emitStackFrameLayoutRemarks(MachineFunction &MF,
     // MFI's ObjectOffset.
     const TargetFrameLowering *FI = MF.getSubtarget().getFrameLowering();
     const int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
 
     LLVM_DEBUG(dbgs() << "getStackProtectorIndex =="
                       << MFI.getStackProtectorIndex() << "\n");
 
     std::vector<SlotData> SlotInfo;
-    SmallDenseMap<int, int> SlotOffsetMap;
 
     const unsigned int NumObj = MFI.getNumObjects();
     SlotInfo.reserve(NumObj);
-    SlotOffsetMap.reserve(NumObj);
     // initialize slot info
     for (int Idx = MFI.getObjectIndexBegin(), EndIdx = MFI.getObjectIndexEnd();
          Idx != EndIdx; ++Idx) {
       if (MFI.isDeadObjectIndex(Idx))
         continue;
-      auto &Inserted = SlotInfo.emplace_back(MFI, ValOffset, Idx);
-      SlotOffsetMap[Inserted.Slot] = Inserted.Offset;
+      SlotInfo.emplace_back(MFI, ValOffset, Idx);
     }
 
     // sort the ordering, to match the actual layout in memory
     llvm::sort(SlotInfo);
 
     SlotDbgMap SlotMap = genSlotDbgMapping(MF);
 
     for (const SlotData &Info : SlotInfo) {

llvm/test/CodeGen/AArch64/arm64-opt-remarks-lazy-bfi.ll

 ; HOTNESS:      Freeing Pass 'Machine Outliner'
 ; HOTNESS-NEXT:  Executing Pass 'Function Pass Manager'
 ; HOTNESS-NEXT: Executing Pass 'Verify generated machine code'
 ; HOTNESS-NEXT: Freeing Pass 'Verify generated machine code'
 ; HOTNESS-NEXT: Executing Pass 'Insert CFI remember/restore state instructions' on Function 'empty_func'
 ; HOTNESS-NEXT: Freeing Pass 'Insert CFI remember/restore state instructions' on Function 'empty_func'
 ; HOTNESS-NEXT: Executing Pass 'Verify generated machine code'
 ; HOTNESS-NEXT: Freeing Pass 'Verify generated machine code'
-; HOTNESS-NEXT: Executing Pass 'Lazy Machine Block Frequency Analysis'
-; HOTNESS-NEXT: Executing Pass 'Machine Optimization Remark Emitter'
-; HOTNESS:      Executing Pass 'Stack Frame Layout Analysis'
-; HOTNESS-NEXT: Freeing Pass 'Machine Optimization Remark Emitter'
-; HOTNESS-NEXT: Freeing Pass 'Lazy Machine Block Frequency Analysis'
-; HOTNESS-NEXT: Freeing Pass 'Stack Frame Layout Analysis'
-; HOTNESS-NEXT: Executing Pass 'Unpack machine instruction bundles'
+; HOTNESS:      Executing Pass 'Unpack machine instruction bundles'
 ; HOTNESS-NEXT: Freeing Pass 'Unpack machine instruction bundles'
 ; HOTNESS-NEXT: Executing Pass 'Verify generated machine code'
 ; HOTNESS-NEXT: Freeing Pass 'Verify generated machine code'
 ; HOTNESS-NEXT: Executing Pass 'Lazy Machine Block Frequency Analysis'
 ; HOTNESS-NEXT: Executing Pass 'Machine Optimization Remark Emitter'
 ; HOTNESS-NEXT: Building MachineBlockFrequencyInfo on the fly
 ; HOTNESS-NEXT: Building LoopInfo on the fly
 ; HOTNESS-NEXT: Building DominatorTree on the fly
 ; HOTNESS-NOT: Executing Pass
 ; HOTNESS: block-frequency: empty_func
 ; HOTNESS-NOT: Executing Pass
 ; HOTNESS: Executing Pass 'AArch64 Assembly Printer'
 
 ; HOTNESS: arm64-summary-remarks.ll:5:0: 1 instructions in function (hotness: 33)
 
 
 ; NO_HOTNESS:      Freeing Pass 'Machine Outliner'
 ; NO_HOTNESS-NEXT:  Executing Pass 'Function Pass Manager'
 ; NO_HOTNESS-NEXT: Executing Pass 'Verify generated machine code'
 ; NO_HOTNESS-NEXT: Freeing Pass 'Verify generated machine code'
 ; NO_HOTNESS-NEXT: Executing Pass 'Insert CFI remember/restore state instructions' on Function 'empty_func'
 ; NO_HOTNESS-NEXT: Freeing Pass 'Insert CFI remember/restore state instructions' on Function 'empty_func'
 ; NO_HOTNESS-NEXT: Executing Pass 'Verify generated machine code'
 ; NO_HOTNESS-NEXT: Freeing Pass 'Verify generated machine code'
-; NO_HOTNESS-NEXT: Executing Pass 'Lazy Machine Block Frequency Analysis'
-; NO_HOTNESS-NEXT: Executing Pass 'Machine Optimization Remark Emitter'
-; NO_HOTNESS:      Executing Pass 'Stack Frame Layout Analysis'
-; NO_HOTNESS-NEXT: Freeing Pass 'Machine Optimization Remark Emitter'
-; NO_HOTNESS-NEXT: Freeing Pass 'Lazy Machine Block Frequency Analysis'
-; NO_HOTNESS-NEXT: Freeing Pass 'Stack Frame Layout Analysis'
-; NO_HOTNESS-NEXT: Executing Pass 'Unpack machine instruction bundles'
+; NO_HOTNESS:      Executing Pass 'Unpack machine instruction bundles'
 ; NO_HOTNESS-NEXT: Freeing Pass 'Unpack machine instruction bundles'
 ; NO_HOTNESS-NEXT: Executing Pass 'Verify generated machine code'
 ; NO_HOTNESS-NEXT: Freeing Pass 'Verify generated machine code'
 ; NO_HOTNESS-NEXT: Executing Pass 'Lazy Machine Block Frequency Analysis'
 ; NO_HOTNESS-NEXT: Executing Pass 'Machine Optimization Remark Emitter'
 ; NO_HOTNESS-NEXT: Executing Pass 'AArch64 Assembly Printer'
 
 ; NO_HOTNESS: arm64-summary-remarks.ll:5:0: 1 instructions in function{{$}}