[DebugInfo] Add debug info to the values emitted in GlobalStructInference

src/passes/GlobalStructInference.cpp

@@ -50,6 +50,7 @@
 
 #include <variant>
 
+#include "ir/debuginfo.h"
 #include "ir/find_all.h"
 #include "ir/module-utils.h"
 #include "ir/names.h"
@@ -417,29 +418,36 @@ struct GlobalStructInference : public Pass {
         // Helper for optimization: Given a Value, returns what we should read
         // for it.
         auto getReadValue = [&](const Value& value) -> Expression* {
+          Expression* ret;
           if (value.isConstant()) {
             // This is known to be a constant, so simply emit an expression for
             // that constant.
-            return value.getConstant().makeExpression(wasm);
-          }
+            ret = value.getConstant().makeExpression(wasm);
+          } else {
+            // Otherwise, this is non-constant, so we are in the situation where
+            // we want to un-nest the value out of the struct.new it is in. Note
+            // that for later work, as we cannot add a global in parallel.
 
-          // Otherwise, this is non-constant, so we are in the situation where
-          // we want to un-nest the value out of the struct.new it is in. Note
-          // that for later work, as we cannot add a global in parallel.
+            // There can only be one global in a value that is not constant,
+            // which is the global we want to read from.
+            assert(value.globals.size() == 1);
 
-          // There can only be one global in a value that is not constant, which
-          // is the global we want to read from.
-          assert(value.globals.size() == 1);
+            // Create a global.get with temporary name, leaving only the
+            // updating of the name to later work.
+            auto* get = builder.makeGlobalGet(value.globals[0],
+                                              value.getExpression()->type);
 
-          // Create a global.get with temporary name, leaving only the updating
-          // of the name to later work.
-          auto* get = builder.makeGlobalGet(value.globals[0],
-                                            value.getExpression()->type);
+            globalsToUnnest.emplace_back(
+              GlobalToUnnest{value.globals[0], fieldIndex, get});
+
+            ret = get;
+          }
 
-          globalsToUnnest.emplace_back(
-            GlobalToUnnest{value.globals[0], fieldIndex, get});
+          // This value replaces the struct.get, so it should have the same
+          // source location.
+          debuginfo::copyOriginalToReplacement(curr, ret, getFunction());
 
-          return get;
+          return ret;
         };
 
         // We have some globals (at least 2), and so must have at least one

test/lit/passes/gsi-debug.wast

@@ -0,0 +1,73 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+;; RUN: env BINARYEN_PRINT_FULL=1 foreach %s %t wasm-opt --gsi -all --closed-world -S -o - | filecheck %s
+
+;; Test that debug info is copied to the values we replace a struct.get with.
+;; We use BINARYEN_PRINT_FULL=1 here because the select that contains the
+;; values also gets that debug info, and normally we omit debug info of children
+;; when it matches the parent (so we could not tell without
+;; BINARYEN_PRINT_FULL=1 whether the children had the debug info or not).
+;; (Another way to test this would be to run a followup optimization to remove
+;; the select, but that would be more complex.)
+
+(module
+  ;; CHECK:      (type $struct (struct (field i32)))
+  (type $struct (struct i32))
+
+  ;; CHECK:      (type $1 (func (param (ref null $struct))))
+
+  ;; CHECK:      (global $global1 (ref $struct) (struct.new $struct
+  ;; CHECK-NEXT:  (i32.const 42) (; i32 ;)
+  ;; CHECK-NEXT: ))
+  (global $global1 (ref $struct) (struct.new $struct
+    (i32.const 42)
+  ))
+
+  ;; CHECK:      (global $global2 (ref $struct) (struct.new $struct
+  ;; CHECK-NEXT:  (i32.const 1337) (; i32 ;)
+  ;; CHECK-NEXT: ))
+  (global $global2 (ref $struct) (struct.new $struct
+    (i32.const 1337)
+  ))
+
+  ;; A non-reference global does not confuse us.
+  ;; CHECK:      (global $global-other i32 (i32.const 123456))
+  (global $global-other i32 (i32.const 123456))
+
+  ;; CHECK:      (func $test (type $1) (param $struct (ref null $struct))
+  ;; CHECK-NEXT:  ;;@ drop.c:10:1
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   ;;@ struct.c:20:2
+  ;; CHECK-NEXT:   (select
+  ;; CHECK-NEXT:    ;;@ struct.c:20:2
+  ;; CHECK-NEXT:    (i32.const 42) (; i32 ;)
+  ;; CHECK-NEXT:    ;;@ struct.c:20:2
+  ;; CHECK-NEXT:    (i32.const 1337) (; i32 ;)
+  ;; CHECK-NEXT:    ;;@
+  ;; CHECK-NEXT:    (ref.eq
+  ;; CHECK-NEXT:     ;;@
+  ;; CHECK-NEXT:     (ref.as_non_null
+  ;; CHECK-NEXT:      ;;@ local.c:30:3
+  ;; CHECK-NEXT:      (local.get $struct) (; struct null ;)
+  ;; CHECK-NEXT:     ) (; struct ;)
+  ;; CHECK-NEXT:     ;;@
+  ;; CHECK-NEXT:     (global.get $global1) (; struct ;)
+  ;; CHECK-NEXT:    ) (; i32 ;)
+  ;; CHECK-NEXT:   ) (; i32 ;)
+  ;; CHECK-NEXT:  ) (; none ;)
+  ;; CHECK-NEXT: )
+  (func $test (param $struct (ref null $struct))
+    ;; We can infer that this get can reference either $global1 or $global2,
+    ;; and nothing else (aside from a null), and can emit a select between
+    ;; those values. While doing so we copy the debug info as well to the
+    ;; values in the select.
+    ;;@ drop.c:10:1
+    (drop
+      ;;@ struct.c:20:2
+      (struct.get $struct 0
+        ;;@ local.c:30:3
+        (local.get $struct)
+      )
+    )
+  )
+)
+