[clang] [analyzer] Workaround for unintended slowdown (scope increase) (PR #136720)

[Balázs Benics via cfe-commits]

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@@ -0,0 +1,198 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -verify=expected,default %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -analyzer-config legacy-inlining-prevention=false -verify=expected,disabled %s
+
+int getNum(void); // Get an opaque number.
+
+void clang_analyzer_numTimesReached(void);
+void clang_analyzer_dump(int arg);
+
+//-----------------------------------------------------------------------------
+// Simple case: inlined function never reaches `analyzer-max-loop`.
+
+int inner_simple(void) {
+  clang_analyzer_numTimesReached(); // expected-warning {{2}}
+  return 42;
+}
+
+int outer_simple(void) {
+  int x = inner_simple();
+  int y = inner_simple();
+  return 53 / (x - y); // expected-warning {{Division by zero}}
+}
+
+//-----------------------------------------------------------------------------
+// Inlined function always reaches `analyzer-max-loop`.
+
+int inner_fixed_loop_1(void) {
+  int i;
+  clang_analyzer_numTimesReached(); // expected-warning {{1}}
+  for (i = 0; i < 10; i++);
+  clang_analyzer_numTimesReached(); // no-warning
+  return 42;
+}
+
+int outer_fixed_loop_1(void) {
+  int x = inner_fixed_loop_1();
+  int y = inner_fixed_loop_1();
+  return 53 / (x - y); // no-warning
+}
+
+//-----------------------------------------------------------------------------
+// Inlined function always reaches `analyzer-max-loop`; inlining is prevented
+// even for different entry points.
+// This test uses `clang_analyzer_dump` and distinct `arg` values because
+// `clang_analyzer_numTimesReached` only counts the paths reaching that node
+// during the analysis of one particular entry point, so it cannot distinguish
+// "two entry points reached this, both with one path" (where the two reports
+// are unified as duplicates by the generic report postprocessing) and "one
+// entry point reached this with one path" (where naturally nothing shows that
+// the second entry point _tried_ to reach it).
+
+int inner_fixed_loop_2(int arg) {
+  // Identical copy of inner_fixed_loop_1
+  int i;
+  clang_analyzer_dump(arg); // expected-warning {{2}}
+  for (i = 0; i < 10; i++);
+  clang_analyzer_dump(arg); // no-warning
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balazs-benics-sonarsource wrote:

FIXME.

https://github.com/llvm/llvm-project/pull/136720