[clang-query] continue querying even if files are skipped

[Lekensteyn]

Summary

Like clang-check, continue even if some source files were not found in
the compilation database. This makes it possible to do search for
matching sources and query files that exist in the compilation db:

clang-query -c 'm callExpr(callee(functionDecl(hasName("function_name"))))' $(grep -rl ^function_name)

Note: buildASTs calls ClangTool::run which returns 1 if any of the
commands failed and 2 otherwise if any of the files were missing.

[Lekensteyn]

test/clang-query/database-missing-entry.c

10

On trunk this fails tests because of https://reviews.llvm.org/D51729. Reverting that patch will properly ignore the missing file.

[Lekensteyn]

Changes:

• Return 1 (instead of 0) if none of the files could be parsed (and add a test for it)
• Propagate any error code (like 2 in case of some missing files) from Tool.buildASTs instead of returning 0.
• Change test to accomodate the change in behavior/output due to https://reviews.llvm.org/D51729 (Thanks to Sam McCall for feedback.)

[Lekensteyn]

This was addressed by https://reviews.llvm.org/D51183 (without new tests though).

clang-query/tool/ClangQuery.cpp

if ((!Commands.empty() || !CommandFiles.empty()) && !PreloadFile.empty()) {
     llvm::errs() << argv[0]
                  << ": cannot specify both -c or -f with --preload\n";
     return 1;
   }
 
   ClangTool Tool(OptionsParser.getCompilations(),
                  OptionsParser.getSourcePathList());
   std::vector<std::unique_ptr<ASTUnit>> ASTs;
-  if (Tool.buildASTs(ASTs) != 0)
+  int RunResult = Tool.buildASTs(ASTs);
+  if (ASTs.empty())
       return 1;
 
   QuerySession QS(ASTs);
 
   if (!Commands.empty()) {
     for (auto I = Commands.begin(), E = Commands.end(); I != E; ++I) {
       QueryRef Q = QueryParser::parse(*I, QS);
       if (!Q->run(llvm::outs(), QS))
         return 1;
while (llvm::Optional<std::string> Line = LE.readLine()) {
       QueryRef Q = QueryParser::parse(*Line, QS);
       Q->run(llvm::outs(), QS);
       llvm::outs().flush();
       if (QS.Terminate)
         break;
     }
   }
 
-  return 0;
+  return RunResult;
 }

test/clang-query/Inputs/database_template.json

+[
+{
+  "directory": "test_dir/build",
+  "command": "clang -DAVAL=8 -o a.o test_dir/src/a.c",
+  "file": "test_dir/src/a.c"
+},
+{
+  "directory": "test_dir/build",
+  "command": "clang -o b.o test_dir/src/b.c",
+  "file": "test_dir/src/b.c"
+}
+]

test/clang-query/database-missing-entry.c

+// RUN: rm -rf %t && mkdir -p %t/src %t/build
+// RUN: sed 's|test_dir|%t|g' %S/Inputs/database_template.json > %t/build/compile_commands.json
+// RUN: echo 'int A = AVAL;' > %t/src/a.c
+// RUN: echo 'deliberate parsing error' > %t/src/b.c
+// RUN: not clang-query -p=%t/build -c "m integerLiteral()" %t/src/a.c %t/src/b.c %t/src/missing.c 2>&1 | FileCheck %s
+
+// Test that neither parse errors nor missing database entries prevent further processing.
+// CHECK: deliberate parsing error
+// CHECK: Error while processing {{.*[/\\]}}missing.c.
+// CHECK-NOT-EXIST: Error while processing {{.*[/\\]}}missing.c.
+// CHECK-NOT-EXIST: unable to handle compilation
+// CHECK: a.c:1:9: note: "root" binds here
+
+// Test that an empty AST due to lack of any source files is bad.
+// RUN: not clang-query -p=%t/build -c "m integerLiteral()" %t/src/missing.c 2>&1 | FileCheck --check-prefix=CHECK-NONE %s
+// CHECK-NONE: Error while processing {{.*[/\\]}}missing.c.