[code-reflection] RFR: 8324789: Add line number information to code models

[Maurizio Cimadamore]

On Wed, 17 Apr 2024 20:24:49 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

> Enable operations to have originating source location information, specifically source reference, line and column information.
> 
> The location information may be set (one or more times) on an operation while it is unbound. Once it is bound, when it is a member of a block and that block is bound, it can no longer be set. Copying an operation will also copy the location. This enables preservation when transforming, especially for lowering.
> 
> The compiler generates location information from a tree node, and sets it on the associated operation(s). For the operations associated with a reflected method (FuncOp) or quoted lambda expression (LambdaOp or ClosureOp) the source reference (a URI) is added to the location, whereas for all other operations the source reference is absent.
> 
> Example:
> 
> 
>     @CodeReflection                          // 47
>     static int f(int n) {                    // 48
>         int sum = 0;                         // 49
>         for (int i = 0; i < n; i++)  {       // 50
>             sum += i;                        // 51
>         }                                    // 52
>         return sum;                          // 53
>     }                                        // 54
> 
> 
> Model:
> 
> 
> func @"f" @loc="47:5:file:///Users/sandoz/Projects/jdk/test/babylon-test/src/test/java/T.java" (%0 : int)int -> {
>     %1 : Var<int> = var %0 @"n" @loc="47:5";
>     %2 : int = constant @"0" @loc="49:19";
>     %3 : Var<int> = var %2 @"sum" @loc="49:9";
>     java.for @loc="50:9"
>         ()Var<int> -> {
>             %4 : int = constant @"0" @loc="50:22";
>             %5 : Var<int> = var %4 @"i" @loc="50:14";
>             yield %5 @loc="50:9";
>         }
>         (%6 : Var<int>)boolean -> {
>             %7 : int = var.load %6 @loc="50:25";
>             %8 : int = var.load %1 @loc="50:29";
>             %9 : boolean = lt %7 %8 @loc="50:25";
>             yield %9 @loc="50:9";
>         }
>         (%10 : Var<int>)void -> {
>             %11 : int = var.load %10 @loc="50:32";
>             %12 : int = constant @"1" @loc="50:32";
>             %13 : int = add %11 %12 @loc="50:32";
>             var.store %10 %13 @loc="50:32";
>             yield @loc="50:9";
>         }
>         (%14 : Var<int>)void -> {
>             %15 : int = var.load %3 @loc="51:13";
>             %16 : int = var.load %14 @loc="51:20";
>             %17 : int = add %15 %16 @loc="51:13";
>             var.store %3 %17 @loc="51:13";
>             java.continue @loc="50:9";
>         };
>     %18 : int = var.load %3 @loc="53:16";
>     return %18 @loc=...

src/java.base/share/classes/java/lang/reflect/code/Op.java line 268:

> 266:      * {@return the originating source location of this operation, otherwise {@code null} if not specified}
> 267:      */
> 268:     public final Location location() {

Should this be returning `Optional`? Or, do we want to have a "no position" (like javac has)?

-------------

PR Review Comment: https://git.openjdk.org/babylon/pull/54#discussion_r1570480441