[clang][cas] Ignore indexing options when computing the CAS key

clang/lib/Frontend/CompileJobCacheKey.cpp

@@ -74,6 +74,20 @@ createCompileJobCacheKeyImpl(ObjectStore &CAS, DiagnosticsEngine &Diags,
   // affect the actual compilation.
   DepOpts.ExtraDeps.clear();
 
+  // Canonicalize indexing options.
+
+  // Indexing data are allowed to "escape" the CAS sandbox without indexing
+  // options affecting the CAS key. Essentially indexing data are produced when
+  // the compilation is executed but they are not replayed if the compilation is
+  // cached.
+
+  FrontendOpts.IndexStorePath.clear();
+  FrontendOpts.IndexUnitOutputPath.clear();
+  FrontendOpts.IndexIgnoreSystemSymbols = false;
+  FrontendOpts.IndexRecordCodegenName = false;
+  FrontendOpts.IndexIgnoreMacros = false;
+  FrontendOpts.IndexIgnorePcms = false;
+
   // Canonicalize diagnostic options.
 
   DiagnosticOptions &DiagOpts = CI.getDiagnosticOpts();

clang/test/CAS/indexing.c

@@ -0,0 +1,19 @@
+// Test that emitted indexing data are allowed to "escape" the CAS sandbox without indexing options affecting the CAS key
+// (essentially indexing data are produced when the compilation is executed but they are not replayed if the compilation is cached)
+
+// RUN: rm -rf %t && mkdir %t
+
+// RUN: %clang -cc1depscan -fdepscan=inline -fdepscan-include-tree -o %t/t.rsp -cc1-args \
+// RUN:   -cc1 -triple x86_64-apple-macos12 -fcas-path %t/cas -emit-obj %s -o %t/t.o
+
+// RUN: %clang @%t/t.rsp -Rcompile-job-cache -index-store-path %t/idx -index-unit-output-path t.o 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CACHE-MISS
+// RUN: find %t/idx/*/records | count 1
+
+// RUN: rm -rf %t/idx && mkdir %t/idx
+// RUN: %clang @%t/t.rsp -Rcompile-job-cache 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CACHE-HIT
+// RUN: ls %t/idx | count 0
+
+// CACHE-MISS: remark: compile job cache miss
+// CACHE-HIT: remark: compile job cache hit