[MIRPrinter] Fix incorrect output of unnamed stack names

[ehjogab]

Summary

The MIRParser expects unnamed stack entries to have empty names ('').
In case of unnamed alloca instructions, the MIRPrinter would output
'<unnamed alloca>', which caused the MIRParser to reject the generated
code.

[arsenm]

The test isn't Generic since it uses aarch64, it should go under AArch64

llvm/test/CodeGen/MIR/Generic/unnamed-stack.ll

1

I didn't know && worked in run lines. Should either use a separate run line with the temp file, or just pipe directly to the second llc

5–6

Probably should check the frame object list too

[dfukalov]

It seems patch should include update for alloca-crspill.ll test (failed Unit Tests precheckin).

[ehjogab]

Moved testcase to correct location
Split RUN into multiple lines
Added check of frame object list
Fixed failing testcase

[dfukalov]

llvm/test/CodeGen/MIR/AArch64/unnamed-stack.ll

1–2 ↗

(On Diff #313497)

As I understand, you don't need the second run line, you can just use the output of the first one with "| FileCheck" and without storing a temporary file.

[arsenm]

llvm/test/CodeGen/MIR/AArch64/unnamed-stack.ll

3 ↗

(On Diff #313497)

Add a brief comment explaining that this checks round tripping anonymous allocas

[dfukalov]

llvm/test/CodeGen/MIR/AArch64/unnamed-stack.ll

3 ↗

(On Diff #313497)

Ok, for roundtrip it can be used like llc -O0 -march aarch64 -global-isel -stop-after=irtranslator -o - %s | llc -x mir llc -march aarch64 -run-pass=none -o - | FileCheck %s without creating a temporary file.

[ehjogab]

Removed use of temporary file.

[uabelho]

I submitted this for @ehjogab

llvm/lib/CodeGen/MIRPrinter.cpp

 //===- MIRPrinter.cpp - MIR serialization format printer ------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the class that prints out the LLVM IR and machine
void MIRPrinter::convertStackObjects(yaml::MachineFunction &YMF,
   for (int I = 0; I < EndIdx; ++I, ++ID) {
     StackObjectsIdx.push_back(-1); // Fill index for possible dead.
     if (MFI.isDeadObjectIndex(I))
       continue;
 
     yaml::MachineStackObject YamlObject;
     YamlObject.ID = ID;
     if (const auto *Alloca = MFI.getObjectAllocation(I))
       YamlObject.Name.Value = std::string(
-          Alloca->hasName() ? Alloca->getName() : "<unnamed alloca>");
+          Alloca->hasName() ? Alloca->getName() : "");
     YamlObject.Type = MFI.isSpillSlotObjectIndex(I)
                           ? yaml::MachineStackObject::SpillSlot
                           : MFI.isVariableSizedObjectIndex(I)
                                 ? yaml::MachineStackObject::VariableSized
                                 : yaml::MachineStackObject::DefaultType;
     YamlObject.Offset = MFI.getObjectOffset(I);
     YamlObject.Size = MFI.getObjectSize(I);
     YamlObject.Alignment = MFI.getObjectAlign(I);

llvm/test/CodeGen/MIR/Generic/unnamed-stack.ll

+; RUN: llc -O0 -march aarch64 -global-isel -stop-after=irtranslator -o %t.mir %s && llc -march aarch64 -run-pass=none -o - %t.mir | FileCheck %s
+
+define i16 @unnamed_stack() {
+entry:
+  ; CHECK-NAME: unnamed_stack
+  ; CHECK:      %0:_(p0) = G_FRAME_INDEX %stack.0
+  %0 = alloca i16
+  %1 = load i16, i16* %0
+  ret i16 %1
+}
+
+define i16 @named_stack() {
+entry:
+  ; CHECK-NAME: named_stack
+  ; CHECK:      %0:_(p0) = G_FRAME_INDEX %stack.0.ptr
+  %ptr = alloca i16
+  %0 = load i16, i16* %ptr
+  ret i16 %0
+}