Better error messages for unsupported statements in kernels

lib/Frontend/nvqpp/ConvertExpr.cpp

@@ -1719,6 +1719,12 @@ bool QuakeBridgeVisitor::VisitCallExpr(clang::CallExpr *x) {
     TODO_loc(loc, "unknown function, " + funcName + ", in cudaq namespace");
   }
 
+  if (func->isVariadic()) {
+    reportClangError(x, mangler,
+                     "cannot call variadic function from quantum kernel");
+    return false;
+  }
+
   // If we get here, and the CallExpr takes qubits or qreg and it must be
   // another kernel call.
   auto mlirFuncTy = cast<FunctionType>(calleeOp.getType());

lib/Frontend/nvqpp/ConvertStmt.cpp

@@ -317,6 +317,8 @@ bool QuakeBridgeVisitor::TraverseCompoundStmt(clang::CompoundStmt *stmt,
           }
           llvm::dbgs() << "]]]\n";
         });
+      } else {
+        reportClangError(cs, mangler, "statement not supported in qpu kernel");
       }
     }
     return true;

lib/Frontend/nvqpp/ConvertType.cpp

@@ -104,7 +104,11 @@ bool QuakeBridgeVisitor::TraverseRecordType(clang::RecordType *t) {
   if (!result)
     return false;
   if (typeStack.size() != typeStackDepth + 1) {
-    assert(typeStack.size() == typeStackDepth);
+    if (typeStack.size() != typeStackDepth) {
+      emitWarning(toLocation(recDecl),
+                  "compiler encountered type traversal issue");
+      return false;
+    }
     if (allowUnknownRecordType)
       pushType(noneTy);
     else {

test/AST-error/inaccessible_variable.cpp

@@ -20,8 +20,12 @@ struct Kernel {
 int main() {
   int i;
   auto f = [&]() __qpu__ { // expected-remark{{An inaccessible symbol}}
-    cudaq::qreg q(i); // expected-error{{symbol is not accessible in this kernel}}
-    mz(q); // expected-error{{symbol is not accessible in this kernel}}
+    cudaq::qreg q(i);
+    // expected-error@-1 {{symbol is not accessible in this kernel}}
+    // expected-error@-2 {{statement not supported in qpu kernel}}
+    mz(q);
+    // expected-error@-1 {{symbol is not accessible in this kernel}}
+    // expected-error@-2 {{statement not supported in qpu kernel}}
   };
   Kernel{}(f);
   return 0;

test/AST-error/statements.cpp

@@ -9,13 +9,15 @@
 // RUN: cudaq-quake -verify %s
 
 #include <cudaq.h>
+#include <iostream>
 
 void foo();
 void bar();
 
 struct S2 {
   auto operator()() __qpu__ {
-    try { // expected-error{{try statement is not yet supported}}
+    try { // expected-error   {{try statement is not yet supported}}
+          // expected-error@-1{{statement not supported in qpu kernel}}
       foo();
     } catch (int) {
       bar();
@@ -25,15 +27,17 @@ struct S2 {
 
 struct S4 {
   auto operator()() __qpu__ {
-    goto label; // expected-error{{goto statement}}
+    goto label; // expected-error   {{goto statement}}
+                // expected-error@-1{{statement not supported in qpu kernel}}
   label:
     foo();
   }
 };
 
 struct S5 {
   auto operator()(int sp) __qpu__ {
-    switch (sp) { // expected-error{{switch statement}}
+    switch (sp) { // expected-error   {{switch statement}}
+                  // expected-error@-1{{statement not supported in qpu kernel}}
     case 1:
       foo();
     default:
@@ -42,3 +46,14 @@ struct S5 {
     }
   }
 };
+
+struct S6 {
+  auto operator()() __qpu__ {
+    // expected-error@+1{{statement not supported in qpu kernel}}
+    std::cout << "Hello\n";
+
+    // expected-error@+2{{cannot call variadic function from quantum kernel}}
+    // expected-error@+1{{statement not supported in qpu kernel}}
+    printf("Hello\n");
+  }
+};