[Lanai] fix MC / objdump

[q3k]

Summary

D78776 removed is{Call,Branch,UnconditionalBranch} guards in objdump
before calling MCInstrAnalysis::evaluateBranch. This is fine for other
architectures as they gracefully handle evaluateBranch being called on
non-branches. However, the Lanai MCInstrAnalysis implementation didn't
and that change caused it to crash.

This inserts the same guards back into Lanai's evaluateBranch
implementation and adds a smoke test that exercises llc | objdump so
this kind of regression is hopefully caught next time.

[jpienaar]

Thanks!

llvm/test/tools/llvm-objdump/ELF/Lanai/smoketest.ll

4 ↗

(On Diff #364579)

s/in to/to/ ?

[MaskRay]

llvm/test/tools/llvm-objdump/ELF/Lanai/smoketest.ll

1 ↗

(On Diff #364579)

; RUN

5 ↗

(On Diff #364579)

Tests in binary utility directories typically use ;; for non-CHECK-non-RUN comments.

[q3k]

Address review comments.

[q3k]

Sorry for the delay, @MaskRay, please take a look now.

[MaskRay]

You may remove test from the filename. The leading test path component says these are tests.

llvm/test/tools/llvm-objdump/ELF/Lanai/smoketest.ll

1 ↗

(On Diff #371637)

delete excess spaces between llc and -o

I usually prefer %t.bc for bitcode output

2 ↗

(On Diff #371637)

[q3k]

Another review comment round.

llvm/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.cpp

 public:
   explicit LanaiMCInstrAnalysis(const MCInstrInfo *Info)
       : MCInstrAnalysis(Info) {}
 
   bool evaluateBranch(const MCInst &Inst, uint64_t Addr, uint64_t Size,
                       uint64_t &Target) const override {
     if (Inst.getNumOperands() == 0)
       return false;
+    if (!isConditionalBranch(Inst) && !isUnconditionalBranch(Inst) &&
+        !isCall(Inst))
+      return false;
 
     if (Info->get(Inst.getOpcode()).OpInfo[0].OperandType ==
         MCOI::OPERAND_PCREL) {
       int64_t Imm = Inst.getOperand(0).getImm();
       Target = Addr + Size + Imm;
       return true;
     } else {
       int64_t Imm = Inst.getOperand(0).getImm();

llvm/test/tools/llvm-objdump/ELF/Lanai/lit.local.cfg

+import platform
+
+if not 'Lanai' in config.root.targets:
+    config.unsupported = True

llvm/test/tools/llvm-objdump/ELF/Lanai/smoke.ll

+; RUN: llc -o %t.bc -filetype=obj -mtriple=lanai %s
+; RUN: llvm-objdump -d -S %t.bc | FileCheck %s
+
+;; Ensure that Lanai can be compiled using llc and then objdumped to
+;; assembly. This is a smoke test to exercise the basics of the MC
+;; implementation in Lanai.
+
+; CHECK-LABEL: smoketest
+; CHECK: st %fp, [--%sp]
+define i32 @smoketest(i32 %x, i32 %y)  {
+  %z = add i32 %x, %y
+  ret i32 %z
+}