[KeyInstr] Fix verifier check (#149043)

The verifier check was in the wrong place, meaning it wasn't actually
checking many instructions.

Fixing that causes a test failure (coro-dwarf-key-instrs.cpp) because
coros turn off the feature but still annotate instructions with the
metadata (which is a supported situation, but the verifier doesn't like
it, and it's hard to teach the verifier to like it).

Fix that by avoiding emitting any key instruction metadata if the
DISubprogram has opted out of key instructions.

Author: OCHyams

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -170,6 +170,10 @@ void CGDebugInfo::addInstToSpecificSourceAtom(llvm::Instruction *KeyInstruction,
   if (!Group || !CGM.getCodeGenOpts().DebugKeyInstructions)
     return;
 
+  llvm::DISubprogram *SP = KeyInstruction->getFunction()->getSubprogram();
+  if (!SP || !SP->getKeyInstructionsEnabled())
+    return;
+
   addInstSourceAtomMetadata(KeyInstruction, Group, /*Rank=*/1);
 
   llvm::Instruction *BackupI =

llvm/lib/IR/Verifier.cpp

@@ -3185,12 +3185,6 @@ void Verifier::visitFunction(const Function &F) {
     CheckDI(SP->describes(&F),
             "!dbg attachment points at wrong subprogram for function", N, &F,
             &I, DL, Scope, SP);
-
-    if (DL->getAtomGroup())
-      CheckDI(DL->getScope()->getSubprogram()->getKeyInstructionsEnabled(),
-              "DbgLoc uses atomGroup but DISubprogram doesn't have Key "
-              "Instructions enabled",
-              DL, DL->getScope()->getSubprogram());
   };
   for (auto &BB : F)
     for (auto &I : BB) {
@@ -5492,6 +5486,15 @@ void Verifier::visitInstruction(Instruction &I) {
   if (MDNode *N = I.getDebugLoc().getAsMDNode()) {
     CheckDI(isa<DILocation>(N), "invalid !dbg metadata attachment", &I, N);
     visitMDNode(*N, AreDebugLocsAllowed::Yes);
+
+    if (auto *DL = dyn_cast<DILocation>(N)) {
+      if (DL->getAtomGroup()) {
+        CheckDI(DL->getScope()->getSubprogram()->getKeyInstructionsEnabled(),
+                "DbgLoc uses atomGroup but DISubprogram doesn't have Key "
+                "Instructions enabled",
+                DL, DL->getScope()->getSubprogram());
+      }
+    }
   }
 
   if (auto *DII = dyn_cast<DbgVariableIntrinsic>(&I)) {

llvm/test/DebugInfo/KeyInstructions/Generic/verify.ll

@@ -7,6 +7,8 @@
 
 define dso_local void @f() !dbg !10 {
 entry:
+; Include non-key location to check verifier is checking the whole function.
+  %0 = add i32 0, 0, !dbg !14
   ret void, !dbg !13
 }
 
@@ -20,3 +22,4 @@ entry:
 !11 = !DISubroutineType(types: !12)
 !12 = !{null}
 !13 = !DILocation(line: 1, column: 11, scope: !10, atomGroup: 1, atomRank: 1)
+!14 = !DILocation(line: 1, column: 11, scope: !10)