[clang] [clang][SSAF] Optionally skip system-header contributors (PR #205446)

[Balázs Benics via cfe-commits]

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@@ -1440,4 +1471,48 @@ TEST_F(PointerFlowTest, ReturnRefPtr) {
   EXPECT_EQ(*Sum, makeEdges(__LINE__, {{{"foo", 1U, true}, {"f", 1U, true}}}));
 }
 
+//////////////////////////////////////////////////////////////
+//          System-header contributor opt-out gate.         //
+//          Spec: tu-summary-extraction,                    //
+//          "System-header contributor opt-out flag".       //
+//////////////////////////////////////////////////////////////
+
+// Default: ExtractFromSystemHeaders == true. A function decl in a
+// `#pragma clang system_header`-marked included header IS enumerated
+// as a contributor and produces an EntitySummary.
+TEST_F(PointerFlowTest, SystemHeader_ExtractDefault) {
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steakhal wrote:

I think we usually use CamelCase all the way.
```suggestion
TEST_F(PointerFlowTest, ExtractFromSystemHeadersByDefault) {
```

https://github.com/llvm/llvm-project/pull/205446