Verifier: fix bug treating debug info issue as non-debug info issue

[yaxunl]

Summary

Normally when llvm-as sees only debug info errors in LLVM assembly, it simply drops the debug info and outputs a valid LLVM bitcode and returns 0.

There is a bug in LLVM verifier which incorrectly treats a debug info error as non-debug info error, which causes llvm-as returns 1 even though llvm-as can drop the invalid debug info and outputs a valid LLVM bitcode.

This patch fixes that.

[aprantl]

Since this can be recovered from by stripping debug info, this change is correct.

Thanks!

lib/IR/Verifier.cpp

       return;
 
   BasicBlock *BB = DII.getParent();
   Function *F = BB ? BB->getParent() : nullptr;
 
   // The scopes for variables and !dbg attachments must agree.
   DILocalVariable *Var = DII.getVariable();
   DILocation *Loc = DII.getDebugLoc();
-  Assert(Loc, "llvm.dbg." + Kind + " intrinsic requires a !dbg attachment",
+  AssertDI(Loc, "llvm.dbg." + Kind + " intrinsic requires a !dbg attachment",
            &DII, BB, F);
 
   DISubprogram *VarSP = getSubprogram(Var->getRawScope());
   DISubprogram *LocSP = getSubprogram(Loc->getRawScope());
   if (!VarSP || !LocSP)
     return; // Broken scope chains are checked elsewhere.
 
   AssertDI(VarSP == LocSP, "mismatched subprogram between llvm.dbg." + Kind +
                                " variable and !dbg attachment",

test/Verifier/llvm.dbg.intrinsic-dbg-attachment.ll

-; RUN: not llvm-as -disable-output <%s 2>&1 | FileCheck %s
+; RUN: llvm-as -disable-output <%s 2>&1 | FileCheck %s
 define void @foo() {
 entry:
   call void @llvm.dbg.value(
       metadata i8* undef,
       metadata !DILocalVariable(scope: !1),
       metadata !DIExpression())
 ; CHECK-LABEL: llvm.dbg.value intrinsic requires a !dbg attachment
 ; CHECK-NEXT: call void @llvm.dbg.value({{.*}})