Make trailing '{' illegal

Author: mgehre-amd

mlir/lib/Dialect/EmitC/IR/EmitC.cpp

@@ -200,9 +200,8 @@ parseFormatString(StringRef toParse, ArgType fmtArgs,
       continue;
     }
     if (toParse.size() < 2) {
-      // '{' is last character
-      items.push_back(toParse);
-      break;
+      return (*emitError)()
+             << "expected '}' after unescaped '{' at end of string";
     }
     // toParse contains at least two characters and starts with `{`.
     char nextChar = toParse[1];

mlir/test/Dialect/EmitC/invalid_ops.mlir

@@ -577,6 +577,14 @@ func.func @test_verbatim(%arg0 : !emitc.ptr<i32>, %arg1 : i32) {
 
 // -----
 
+func.func @test_verbatim(%arg0 : !emitc.ptr<i32>, %arg1 : i32) {
+  // expected-error @+1 {{'emitc.verbatim' op expected '}' after unescaped '{' at end of string}}
+  emitc.verbatim "{} + {} {" args %arg0, %arg1 : !emitc.ptr<i32>, i32
+  return
+}
+
+// -----
+
 func.func @test_verbatim(%arg0 : !emitc.ptr<i32>, %arg1 : i32) {
   // expected-error @+1 {{'emitc.verbatim' op requires operands for each placeholder in the format string}}
   emitc.verbatim "abc" args %arg0, %arg1 : !emitc.ptr<i32>, i32

mlir/test/Dialect/EmitC/ops.mlir

@@ -244,9 +244,6 @@ emitc.verbatim "{} {  }"
 func.func @test_verbatim(%arg0 : !emitc.ptr<i32>, %arg1 : i32) {
   emitc.verbatim "{} + {};" args %arg0, %arg1 : !emitc.ptr<i32>, i32
 
-  // Trailing '{' are ok and don't start a placeholder.
-  emitc.verbatim "{} + {} {" args %arg0, %arg1 : !emitc.ptr<i32>, i32
-
   // Check there is no ambiguity whether %a is the argument to the emitc.verbatim op.
   emitc.verbatim "a"
   %a = "emitc.constant"(){value = 42 : i32} : () -> i32

mlir/test/Target/Cpp/verbatim.mlir

@@ -34,10 +34,6 @@ emitc.func @func(%arg: f32) {
   emitc.verbatim "#pragma my var={} property" args %arg : f32
   // CHECK-NEXT: #pragma my var=[[V0]] property
 
-  // Trailing '{' are printed as-is.
-  emitc.verbatim "#pragma my var={} {" args %arg : f32
-  // CHECK-NEXT: #pragma my var=[[V0]] {
-
   emitc.verbatim "#pragma my2 var={} property" args %a : !emitc.array<3x7xi32>
   // CHECK-NEXT: #pragma my2 var=[[A]] property