[analyzer] Fix ctu-on-demand-parsing: REQUIRES: linux -> REQUIRES: system-linux

[steakhal]

Summary

AFAIK there is no such feature as linux.
I think this should be system-linux

linux and freebsd requirement tags were used by other projects like XRay.
I'm not sure if those tests are skipped or not. I would really appreciate any feedback on this.

The relevant test infra code segment is this - I think:
https://github.com/llvm/llvm-project/blob/master/llvm/utils/lit/lit/llvm/config.py#L54-L55

elif platform.system() == 'Linux':
    features.add('system-linux')

BTW on my system (Ubuntu 18.04), the patched tests were marked UNSUPPORTED.
After the fix, they all PASSed.

[gamesh411]

Good thing you were looking inside the test infra code to catch this, kudos!

[gamesh411]

In addition, IMHO the test infra should then be extended to throw an exception, when a feature is referenced that is not mentioned anywhere. That would be helpful in the future.

[martong]

Thanks!

clang/test/Analysis/ctu-on-demand-parsing.c

 // RUN: cd "%t" && %clang_cc1 -fsyntax-only -std=c89 -analyze \
 // RUN:   -analyzer-checker=core,debug.ExprInspection \
 // RUN:   -analyzer-config experimental-enable-naive-ctu-analysis=true \
 // RUN:   -analyzer-config ctu-dir=. \
 // RUN:   -analyzer-config ctu-invocation-list=invocations.yaml \
 // RUN:   -verify ctu-on-demand-parsing.c
 //
 // FIXME: Path handling should work on all platforms.
-// REQUIRES: linux
+// REQUIRES: system-linux
 
 void clang_analyzer_eval(int);
 
 // Test typedef and global variable in function.
 typedef struct {
   int a;
   int b;
 } FooBar;

clang/test/Analysis/ctu-on-demand-parsing.cpp

 // RUN:   -analyzer-config ctu-dir=. \
 // RUN:   -analyzer-config ctu-invocation-list=invocations.yaml \
 // RUN:   -analyzer-config display-ctu-progress=true ctu-on-demand-parsing.cpp 2>&1 | FileCheck %t/ctu-on-demand-parsing.cpp
 //
 // CHECK: CTU loaded AST file: {{.*}}ctu-other.cpp
 // CHECK: CTU loaded AST file: {{.*}}ctu-chain.cpp
 //
 // FIXME: Path handling should work on all platforms.
-// REQUIRES: linux
+// REQUIRES: system-linux
 
 #include "ctu-hdr.h"
 
 void clang_analyzer_eval(int);
 
 int f(int);
 int g(int);
 int h(int);