From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001
From: "Matt A. Tobin" <mattatobin@localhost.localdomain>
Date: Fri, 2 Feb 2018 04:16:08 -0500
Subject: Add m-esr52 at 52.6.0

---
 .../devtools/rootAnalysis/t/exceptions/source.cpp  | 42 ++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 js/src/devtools/rootAnalysis/t/exceptions/source.cpp

(limited to 'js/src/devtools/rootAnalysis/t/exceptions/source.cpp')

diff --git a/js/src/devtools/rootAnalysis/t/exceptions/source.cpp b/js/src/devtools/rootAnalysis/t/exceptions/source.cpp
new file mode 100644
index 000000000..14169740e
--- /dev/null
+++ b/js/src/devtools/rootAnalysis/t/exceptions/source.cpp
@@ -0,0 +1,42 @@
+#define ANNOTATE(property) __attribute__((tag(property)))
+
+struct Cell { int f; } ANNOTATE("GC Thing");
+
+extern void GC() ANNOTATE("GC Call");
+
+void GC()
+{
+    // If the implementation is too trivial, the function body won't be emitted at all.
+    asm("");
+}
+
+class RAII_GC {
+  public:
+    RAII_GC() {}
+    ~RAII_GC() { GC(); }
+};
+
+// ~AutoSomething calls GC because of the RAII_GC field. The constructor,
+// though, should *not* GC -- unless it throws an exception. Which is not
+// possible when compiled with -fno-exceptions.
+class AutoSomething {
+    RAII_GC gc;
+  public:
+    AutoSomething() : gc() {
+        asm(""); // Ooh, scary, this might throw an exception
+    }
+    ~AutoSomething() {
+        asm("");
+    }
+};
+
+extern void usevar(Cell* cell);
+
+void f() {
+    Cell* thing = nullptr; // Live range starts here
+
+    {
+        AutoSomething smth; // Constructor can GC only if exceptions are enabled
+        usevar(thing); // Live range ends here
+    } // In particular, 'thing' is dead at the destructor, so no hazard
+}
-- 
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