[clang] [clang][scan-deps] Report a scanned TU's visible modules (PR #147969)

[Jan Svoboda via cfe-commits]

================
@@ -0,0 +1,116 @@
+// This test verifies that the modules visible to the translation unit are computed in dependency scanning.
+// "client" in the first scan represents the translation unit that imports an explicit submodule, 
+//    that only exports one other module. 
+// In the second scan, the translation unit that imports an explicit submodule, 
+//    that exports an additional module. 
+// Thus, the dependencies of the top level module for the submodule always differ from what is visible to the TU.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: sed -e "s|DIR|%/t|g" %t/compile-commands.json.in > %t/compile-commands.json
+// RUN: clang-scan-deps -emit-visible-modules -compilation-database %t/compile-commands.json \
+// RUN:   -j 1 -format experimental-full 2>&1 > %t/result-first-scan.json
+// RUN: cat %t/result-first-scan.json | sed 's:\\\\\?:/:g' | FileCheck %s -DPREFIX=%/t --check-prefix=SINGLE
+
+/// Re-run scan with different module map for direct dependency.
+// RUN: mv %t/A_without_visible_export.modulemap %t/Sysroot/usr/include/A/module.modulemap
+// RUN: clang-scan-deps -emit-visible-modules -compilation-database %t/compile-commands.json \
+// RUN:   -j 1 -format experimental-full 2>&1 > %t/result.json
+// RUN: cat %t/result.json | sed 's:\\\\\?:/:g' | FileCheck %s -DPREFIX=%/t --check-prefix=MULTIPLE
+
+// RUN: %deps-to-rsp %t/result.json --module-name=transitive > %t/transitive.rsp
+// RUN: %deps-to-rsp %t/result.json --module-name=visible > %t/visible.rsp
+// RUN: %deps-to-rsp %t/result.json --module-name=invisible > %t/invisible.rsp
+// RUN: %deps-to-rsp %t/result.json --module-name=A > %t/A.rsp
+// RUN: %deps-to-rsp %t/result.json --tu-index=0 > %t/tu.rsp
+
+// RUN: %clang @%t/transitive.rsp
+// RUN: %clang @%t/visible.rsp
+// RUN: %clang @%t/invisible.rsp
+// RUN: %clang @%t/A.rsp
+
+/// Verify compilation & scan agree with each other.
+// RUN: not %clang @%t/tu.rsp 2>&1 | FileCheck %s --check-prefix=COMPILE
+
+// SINGLE:        "visible-clang-modules": [
+// SINGLE-NEXT:     "A"
+// SINGLE-NEXT:   ]
+
+// MULTIPLE:        "visible-clang-modules": [
+// MULTIPLE-NEXT:     "A",
+// MULTIPLE-NEXT:     "visible"
+// MULTIPLE-NEXT:   ]
+
+// COMPILE-NOT:   'visible_t' must be declared before it is used
+// COMPILE:       'transitive_t' must be declared before it is used
+// COMPILE:       'invisible_t' must be declared before it is used
+
+//--- compile-commands.json.in
+[
+{
+  "directory": "DIR",
+  "command": "clang -c DIR/client.c -isysroot DIR/Sysroot -IDIR/Sysroot/usr/include -fmodules -fmodules-cache-path=DIR/module-cache -fimplicit-module-maps",
+  "file": "DIR/client.c"
+}
+]
+
+//--- Sysroot/usr/include/A/module.modulemap
+module A {
+  explicit module visibleToTU {
+    header "visibleToTU.h"
+  }
+  explicit module invisibleToTU {
+    header "invisibleToTU.h" 
+  }
+}
+
+//--- A_without_visible_export.modulemap
----------------
jansvoboda11 wrote:

```suggestion
//--- A_with_visible_export.modulemap
```

https://github.com/llvm/llvm-project/pull/147969