Add option -verify-cfiinstrs to run verifier in CFIInstrInserter

[petarj]

Summary

Instead of enabling it for non NDEBUG builds, use -verify-cfiinstrs to
run verifier in CFIInstrInserter. It defaults to false.

[vlad.tsyrklevich]

Seems like there should also be a test case that triggers the verify failure.

[petarj]

In D46444#1088296, @vlad.tsyrklevich wrote:

Seems like there should also be a test case that triggers the verify failure.

If you are referring to the llvm.trap() issue, that will be part of a separate patch and a test case.
There appears to be an issue with inconsistent incoming offsets for 'noreturn' basic blocks.

But also makes sense to have a test case that uses the option and triggers the failure.
Will do that.

[thegameg]

Instead of adding a new flag, would it be possible to make this part of the machine verifier? (-verify-machineinstrs)

[petarj]

In D46444#1088564, @thegameg wrote:

Instead of adding a new flag, would it be possible to make this part of the machine verifier? (-verify-machineinstrs)

Good idea to try to merge it into Machine Verifier later. Right now, we need to make it optional so it does not break anyone's code.

[petarj]

Adding the test cases for -verify-cfiinstrs.

[violetav]

LGTM

llvm/trunk/lib/CodeGen/CFIInstrInserter.cpp

 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/TargetFrameLowering.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
+static cl::opt<bool> VerifyCFI("verify-cfiinstrs",
+    cl::desc("Verify Call Frame Information instructions"),
+    cl::init(false),
+    cl::Hidden);
+
 namespace {
 class CFIInstrInserter : public MachineFunctionPass {
  public:
   static char ID;
 
   CFIInstrInserter() : MachineFunctionPass(ID) {
     initializeCFIInstrInserterPass(*PassRegistry::getPassRegistry());
   }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesAll();
     MachineFunctionPass::getAnalysisUsage(AU);
   }
 
   bool runOnMachineFunction(MachineFunction &MF) override {
     if (!MF.getMMI().hasDebugInfo() &&
         !MF.getFunction().needsUnwindTableEntry())
       return false;
 
     MBBVector.resize(MF.getNumBlockIDs());
     calculateCFAInfo(MF);
-#ifndef NDEBUG
+
+    if (VerifyCFI) {
       if (unsigned ErrorNum = verify(MF))
         report_fatal_error("Found " + Twine(ErrorNum) +
                            " in/out CFI information errors.");
-#endif
+    }
     bool insertedCFI = insertCFIInstrs(MF);
     MBBVector.clear();
     return insertedCFI;
   }
 
  private:
   struct MBBCFAInfo {
     MachineBasicBlock *MBB;

llvm/trunk/test/CodeGen/X86/cfi-inserter-verify-inconsistent-offset.mir

+# RUN: not llc -o - %s -mtriple=x86_64-- -verify-cfiinstrs \
+# RUN:     -run-pass=cfi-instr-inserter 2>&1 | FileCheck %s
+# Test that CFI verifier finds inconsistent offset between bb.end and one of
+# its precedessors.
+--- |
+  define void @inconsistentOffset() {
+    bb.end:
+      ret void
+  }
+...
+---
+# CHECK: *** Inconsistent CFA register and/or offset between pred and succ ***
+# CHECK: Succ: bb.end
+# CHECK: LLVM ERROR: Found 1 in/out CFI information errors.
+name: inconsistentOffset
+body: |
+  bb.0:
+    CFI_INSTRUCTION def_cfa_offset 24
+    JNE_1 %bb.2, implicit undef $eflags
+
+  bb.1:
+    CFI_INSTRUCTION def_cfa_offset 32
+
+  bb.2.bb.end:
+    RET 0
+...

llvm/trunk/test/CodeGen/X86/cfi-inserter-verify-inconsistent-register.mir

+# RUN: not llc -o - %s -mtriple=x86_64-- -verify-cfiinstrs \
+# RUN:     -run-pass=cfi-instr-inserter 2>&1 | FileCheck %s
+# Test that CFI verifier finds inconsistent register between bb.end and one of
+# its precedessors.
+--- |
+  define void @inconsistentRegister() {
+    bb.end:
+      ret void
+  }
+...
+---
+# CHECK: *** Inconsistent CFA register and/or offset between pred and succ ***
+# CHECK: Succ: bb.end
+# CHECK: LLVM ERROR: Found 1 in/out CFI information errors.
+name: inconsistentRegister
+body: |
+  bb.0:
+    CFI_INSTRUCTION def_cfa_register $rbp
+    JNE_1 %bb.2, implicit undef $eflags
+
+  bb.1:
+    CFI_INSTRUCTION def_cfa $rsp, 8
+
+  bb.2.bb.end:
+    RET 0
+...