[clang][deps] Remove hard-coded resource directory from tests

Dependency scanner test for resource directory deduction doesn't account for LLVM builds with custom `CLANG_RESOURCE_DIR`.

This patch ensures we don't hardcode the default behavior into the test and take into account the actual value. This is done by running `%clang -print-resource-dir` and using that as the expected value in test assertions.
New comment also clarifies this is different from running that command as part of the dependency scan.

Reviewed By: mgorny

Differential Revision: https://reviews.llvm.org/D115628

Author: jansvoboda11

clang/test/ClangScanDeps/Inputs/resource_directory/compiler

@@ -5,21 +5,42 @@
 
 // Deduce the resource directory from the compiler path.
 //
-// RUN: sed -e "s|CLANG|/our/custom/bin/clang|g" -e "s|DIR|%/t|g" \
+// With `%clang-scan-deps --resource-dir-recipe modify-compiler-path`, the
+// resource directory should be identical to `%clang -print-resource-dir`.
+// (Assuming both binaries are built from the same Git checkout.)
+// Here we get the expected path by running `%clang -print-resource-dir` and
+// then verify `%clang-scan-deps` arrives at the same path by calling the
+// `Driver::GetResourcesPath` function.
+//
+// RUN: EXPECTED_RESOURCE_DIR=`%clang -print-resource-dir`
+// RUN: sed -e "s|CLANG|%clang|g" -e "s|DIR|%/t|g" \
 // RUN:   %S/Inputs/resource_directory/cdb.json.template > %t/cdb_path.json
+//
 // RUN: clang-scan-deps -compilation-database %t/cdb_path.json --format experimental-full \
 // RUN:   --resource-dir-recipe modify-compiler-path > %t/result_path.json
-// RUN: cat %t/result_path.json | sed 's:\\\\\?:/:g' | FileCheck %s --check-prefix=CHECK-PATH
+// RUN: cat %t/result_path.json | sed 's:\\\\\?:/:g' \
+// RUN:   | FileCheck %s --check-prefix=CHECK-PATH -DEXPECTED_RESOURCE_DIR="$EXPECTED_RESOURCE_DIR"
 // CHECK-PATH:      "-resource-dir"
-// CHECK-PATH-NEXT: "/our/custom/lib{{.*}}"
+// CHECK-PATH-NEXT: "[[EXPECTED_RESOURCE_DIR]]"
 
 // Run the compiler and ask it for the resource directory.
 //
+// With `%clang-scan-deps --resource-dir-recipe invoke-compiler`, the resource
+// directory should be identical to `<clang> -print-resource-dir`, where <clang>
+// is an arbitrary version of Clang. (This configuration is not really supported.)
+// Here we hard-code the expected path into `%t/compiler` and then verify
+// `%clang-scan-deps` arrives at the path by actually running the executable.
+//
+// RUN: EXPECTED_RESOURCE_DIR="/custom/compiler/resources"
+// RUN: echo "#!/bin/sh"                      > %t/compiler
+// RUN: echo "echo '$EXPECTED_RESOURCE_DIR'" >> %t/compiler
 // RUN: chmod +x %t/compiler
 // RUN: sed -e "s|CLANG|%/t/compiler|g" -e "s|DIR|%/t|g" \
 // RUN:   %S/Inputs/resource_directory/cdb.json.template > %t/cdb_invocation.json
+//
 // RUN: clang-scan-deps -compilation-database %t/cdb_invocation.json --format experimental-full \
 // RUN:   --resource-dir-recipe invoke-compiler > %t/result_invocation.json
-// RUN: cat %t/result_invocation.json | sed 's:\\\\\?:/:g' | FileCheck %s --check-prefix=CHECK-INVOCATION
+// RUN: cat %t/result_invocation.json | sed 's:\\\\\?:/:g' \
+// RUN:   | FileCheck %s --check-prefix=CHECK-PATH -DEXPECTED_RESOURCE_DIR="$EXPECTED_RESOURCE_DIR"
 // CHECK-INVOCATION:      "-resource-dir"
-// CHECK-INVOCATION-NEXT: "/custom/compiler/resources"
+// CHECK-INVOCATION-NEXT: "[[EXPECTED_RESOURCE_DIR]]"