[llvm-exegesis][AArch64] Add return statement at the end of the snippet correctly

[kpdev42]

Summary

Currently llvm-exegesis fails to do this which causes every snippet to crash

~~

Huawei RRI, OS Lab

[tstellar]

Hi, this test is failing on s390x, with this error:

FAIL: LLVM :: tools/llvm-exegesis/AArch64/add-return.s (43034 of 46221)
******************** TEST 'LLVM :: tools/llvm-exegesis/AArch64/add-return.s' FAILED ********************
Script:
--
: 'RUN: at line 1';   /builddir/build/BUILD/llvm-17.0.0.src/redhat-linux-build/bin/llvm-exegesis --opcode-name=ADDv16i8 --mcpu=cortex-a78 --mtriple=aarch64-linux-gnu                --mode=latency --benchmark-phase=assemble-measured-code 2>&1 | /builddir/build/BUILD/llvm-17.0.0.src/redhat-linux-build/bin/FileCheck /builddir/build/BUILD/llvm-17.0.0.src/test/tools/llvm-exegesis/AArch64/add-return.s
--
Exit Code: 1

Command Output (stderr):
--
/builddir/build/BUILD/llvm-17.0.0.src/test/tools/llvm-exegesis/AArch64/add-return.s:5:10: error: CHECK: expected string not found in input
# CHECK: assembled_snippet: {{.*}}C0035FD6
         ^
<stdin>:1:1: note: scanning from here
setRegTo is not implemented, results will be unreliable
^
<stdin>:5:200: note: possible intended match here
0. Program arguments: /builddir/build/BUILD/llvm-17.0.0.src/redhat-linux-build/bin/llvm-exegesis --opcode-name=ADDv16i8 --mcpu=cortex-a78 --mtriple=aarch64-linux-gnu --mode=latency --benchmark-phase=assemble-measured-code
                                                                                                                                                                                                       ^

Input file: <stdin>
Check file: /builddir/build/BUILD/llvm-17.0.0.src/test/tools/llvm-exegesis/AArch64/add-return.s

-dump-input=help explains the following input dump.

Input was:
<<<<<<
           1: setRegTo is not implemented, results will be unreliable 
check:5'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
           2: setRegTo is not implemented, results will be unreliable 
check:5'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           3: PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace. 
check:5'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           4: Stack dump: 
check:5'0     ~~~~~~~~~~~~
           5: 0. Program arguments: /builddir/build/BUILD/llvm-17.0.0.src/redhat-linux-build/bin/llvm-exegesis --opcode-name=ADDv16i8 --mcpu=cortex-a78 --mtriple=aarch64-linux-gnu --mode=latency --benchmark-phase=assemble-measured-code 
check:5'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:5'1                                                                                                                                                                                                            ?                       possible intended match
           6:  #0 0x0000000002c0f012 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /builddir/build/BUILD/llvm-17.0.0.src/lib/Support/Unix/Signals.inc:602:13 
check:5'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           7:  #1 0x0000000002c0faf0 llvm::sys::RunSignalHandlers() /builddir/build/BUILD/llvm-17.0.0.src/lib/Support/Signals.cpp:105:18 
check:5'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           8:  #2 0x0000000002c0faf0 SignalHandler(int) /builddir/build/BUILD/llvm-17.0.0.src/lib/Support/Unix/Signals.inc:403:3 
check:5'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           9:  #3 0x000003fff30fe488 (linux-vdso64.so.1+0x488) 
check:5'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          10:  #4 0x000003ffbcb0dbc0 (/lib64/libgcc_s.so.1+0xdbc0) 
check:5'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           .
           .
           .
>>>>>>

--

[tstellar]

Ping on this, can we revert or fix this? I don't think running the aarch64 tests on a big-endian system is really supported. This is the same kind of crash that prompted by to write D145763.

[kpdev42]

In D147699#4274228, @tstellar wrote:

Ping on this, can we revert or fix this? I don't think running the aarch64 tests on a big-endian system is really supported. This is the same kind of crash that prompted by to write D145763.

Sure, will try to fix it

[kpdev42]

In D147699#4276622, @kpdev42 wrote:

In D147699#4274228, @tstellar wrote:

Ping on this, can we revert or fix this? I don't think running the aarch64 tests on a big-endian system is really supported. This is the same kind of crash that prompted by to write D145763.

Sure, will try to fix it

Add a patch https://reviews.llvm.org/D148807

llvm/test/tools/llvm-exegesis/AArch64/add-return.s

+# RUN: llvm-exegesis --opcode-name=ADDv16i8 --mcpu=cortex-a78 --mtriple=aarch64-linux-gnu \
+# RUN:               --mode=latency --benchmark-phase=assemble-measured-code 2>&1 | FileCheck %s
+
+# Check that we add ret (bx lr) instr to snippet
+# CHECK: assembled_snippet: {{.*}}C0035FD6

llvm/tools/llvm-exegesis/lib/Assembler.cpp

void BasicBlockFiller::addReturn(const DebugLoc &DL) {
   if (TII->getReturnOpcode() < TII->getNumOpcodes()) {
     BuildMI(MBB, DL, TII->get(TII->getReturnOpcode()));
   } else {
     MachineIRBuilder MIB(MF);
     MIB.setMBB(*MBB);
 
     FunctionLoweringInfo FuncInfo;
     FuncInfo.CanLowerReturn = true;
-    MF.getSubtarget().getCallLowering()->lowerReturn(MIB, nullptr, {},
-                                                     FuncInfo);
+    MF.getSubtarget().getCallLowering()->lowerReturn(MIB, nullptr, {}, FuncInfo,
+                                                     0);
   }
 }
 
 FunctionFiller::FunctionFiller(MachineFunction &MF,
                                std::vector<unsigned> RegistersSetUp)
     : MF(MF), MCII(MF.getTarget().getMCInstrInfo()), Entry(addBasicBlock()),
       RegistersSetUp(std::move(RegistersSetUp)) {}