[clang-scan-deps] Add even proper-er dependency targets

[arphaman]

LGTM with one suggestion

clang/tools/clang-scan-deps/ClangScanDeps.cpp

210

Please use bool flags for LastMT/MQ/MD (HasMT?) as you don't need their values.

[jkorous]

clang/tools/clang-scan-deps/ClangScanDeps.cpp

210

My bad. Absolutely!

clang/test/ClangScanDeps/Inputs/subframework_header_dir_symlink_cdb.json

 [
 {
   "directory": "DIR",
   "command": "clang -E DIR/subframework_header_dir_symlink_input.m -D EMPTY -iframework Inputs/frameworks",
-  "file": "DIR/subframework_header_dir_symlink.m"
+  "file": "DIR/subframework_header_dir_symlink_input.m"
 },
 {
   "directory": "DIR",
   "command": "clang -E DIR/subframework_header_dir_symlink_input2.m -FInputs/frameworks -iframework Inputs/frameworks_symlink",
-  "file": "DIR/subframework_header_dir_symlink2.m"
+  "file": "DIR/subframework_header_dir_symlink_input2.m"
 }
 ]

clang/test/ClangScanDeps/Inputs/symlink_cdb.json

 [
 {
   "directory": "DIR",
   "command": "clang -E DIR/symlink_input.cpp -IInputs",
-  "file": "DIR/symlink.cpp"
+  "file": "DIR/symlink_input.cpp"
 },
 {
   "directory": "DIR",
   "command": "clang -E DIR/symlink_input2.cpp -IInputs",
-  "file": "DIR/symlink2.cpp"
+  "file": "DIR/symlink_input2.cpp"
 }
 ]

clang/test/ClangScanDeps/Inputs/vfsoverlay_cdb.json

 [
 {
   "directory": "DIR",
   "command": "clang -E DIR/vfsoverlay_input.cpp -IInputs -ivfsoverlay DIR/vfsoverlay.yaml",
-  "file": "DIR/vfsoverlay.cpp"
+  "file": "DIR/vfsoverlay_input.cpp"
 }
 ]

clang/test/ClangScanDeps/header_stat_before_open.m

 // RUN: rm -rf %t.dir
 // RUN: rm -rf %t.cdb
 // RUN: mkdir -p %t.dir
 // RUN: cp %s %t.dir/header_stat_before_open_input.m
 // RUN: mkdir %t.dir/Inputs
 // RUN: cp -R %S/Inputs/frameworks %t.dir/Inputs/frameworks
 // RUN: sed -e "s|DIR|%/t.dir|g" %S/Inputs/header_stat_before_open_cdb.json > %t.cdb
 //
 // RUN: clang-scan-deps -compilation-database %t.cdb -j 1 | \
 // RUN:   FileCheck %s
 
 #include "Framework/Framework.h"
 #include "Framework/PrivateHeader.h"
 
-// CHECK: clang-scan-deps dependency
+// CHECK: header_stat_before_open_input.o
 // CHECK-NEXT: header_stat_before_open_input.m
 // CHECK-NEXT: Inputs{{/|\\}}frameworks{{/|\\}}Framework.framework{{/|\\}}Headers{{/|\\}}Framework.h
 // CHECK-NEXT: Inputs{{/|\\}}frameworks{{/|\\}}Framework.framework{{/|\\}}PrivateHeaders{{/|\\}}PrivateHeader.h

clang/test/ClangScanDeps/regular_cdb.cpp

 // RUN: clang-scan-deps -compilation-database %t.cdb -j 2 -mode preprocess-minimized-sources | \
 // RUN:   FileCheck --check-prefix=CHECK2 %s
 // RUN: clang-scan-deps -compilation-database %t.cdb -j 2 -mode preprocess | \
 // RUN:   FileCheck --check-prefix=CHECK2 %s
 
 #include "header.h"
 
 // CHECK1: regular_cdb_input2.cpp
+// CHECK1-NEXT: regular_cdb_input2.cpp
 // CHECK1-NEXT: Inputs{{/|\\}}header.h
 // CHECK1-NEXT: Inputs{{/|\\}}header2.h
 
 // CHECK2: regular_cdb_input.cpp
 // CHECK2-NEXT: Inputs{{/|\\}}header.h
 // CHECK2NO-NOT: header2

clang/test/ClangScanDeps/subframework_header_dir_symlink.m

 // RUN:   FileCheck %s
 // RUN: clang-scan-deps -compilation-database %t.cdb -j 1 -reuse-filemanager=1 | \
 // RUN:   FileCheck %s
 
 #ifndef EMPTY
 #include "Framework/Framework.h"
 #endif
 
-// CHECK: clang-scan-deps dependency
+// CHECK: subframework_header_dir_symlink_input.o
 // CHECK-NEXT: subframework_header_dir_symlink_input.m
-// CHECK: clang-scan-deps dependency
+// CHECK: subframework_header_dir_symlink_input2.o
 // CHECK-NEXT: subframework_header_dir_symlink_input2.m
 // CHECK-NEXT: Inputs{{/|\\}}frameworks_symlink{{/|\\}}Framework.framework{{/|\\}}Headers{{/|\\}}Framework.h

clang/test/ClangScanDeps/vfsoverlay.cpp

 // RUN: rm -rf %t.dir
 // RUN: rm -rf %t.cdb
 // RUN: mkdir -p %t.dir
 // RUN: cp %s %t.dir/vfsoverlay_input.cpp
 // RUN: sed -e "s|DIR|%/t.dir|g" %S/Inputs/vfsoverlay.yaml > %t.dir/vfsoverlay.yaml
 // RUN: mkdir %t.dir/Inputs
 // RUN: cp %S/Inputs/header.h %t.dir/Inputs/header.h
 // RUN: sed -e "s|DIR|%/t.dir|g" %S/Inputs/vfsoverlay_cdb.json > %t.cdb
 //
 // RUN: clang-scan-deps -compilation-database %t.cdb -j 1 | \
 // RUN:   FileCheck %s
 
 #include "not_real.h"
 
-// CHECK: clang-scan-deps dependency
+// CHECK: vfsoverlay_input.o
 // CHECK-NEXT: vfsoverlay_input.cpp
 // CHECK-NEXT: Inputs{{/|\\}}header.h

clang/tools/clang-scan-deps/ClangScanDeps.cpp

 
 llvm::cl::opt<bool> ReuseFileManager(
     "reuse-filemanager",
     llvm::cl::desc("Reuse the file manager and its cache between invocations."),
     llvm::cl::init(true), llvm::cl::cat(DependencyScannerCategory));
 
 } // end anonymous namespace
 
+/// \returns object-file path derived from source-file path.
+static std::string getObjFilePath(StringRef SrcFile) {
+  SmallString<128> ObjFileName(SrcFile);
+  llvm::sys::path::replace_extension(ObjFileName, "o");
+  return ObjFileName.str();
+}
+
 int main(int argc, const char **argv) {
   llvm::InitLLVM X(argc, argv);
   llvm::cl::HideUnrelatedOptions(DependencyScannerCategory);
   if (!llvm::cl::ParseCommandLineOptions(argc, argv))
     return 1;
 
   std::string ErrorMessage;
   std::unique_ptr<tooling::JSONCompilationDatabase> Compilations =
int main(int argc, const char **argv) {
   for (const auto &Command : Compilations->getAllCompileCommands())
     Inputs.emplace_back(Command.Filename, Command.Directory);
 
   // The command options are rewritten to run Clang in preprocessor only mode.
   auto AdjustingCompilations =
       std::make_unique<tooling::ArgumentsAdjustingCompilations>(
           std::move(Compilations));
   AdjustingCompilations->appendArgumentsAdjuster(
-      [](const tooling::CommandLineArguments &Args, StringRef /*unused*/) {
+      [](const tooling::CommandLineArguments &Args, StringRef FileName) {
+        std::string LastO = "";
+        std::string LastMT = "";
+        std::string LastMQ = "";
+        std::string LastMD = "";
+        // We need to find the last -o value.
+        if (!Args.empty()) {
+          std::size_t Idx = Args.size() - 1;
+          for (auto It = Args.rbegin(); It != Args.rend(); ++It) {
+            if (It != Args.rbegin()) {
+              if (Args[Idx] == "-o")
+                LastO = Args[Idx + 1];
+              if (Args[Idx] == "-MT")
+                LastMT = Args[Idx + 1];
+              if (Args[Idx] == "-MQ")
+                LastMQ = Args[Idx + 1];
+              if (Args[Idx] == "-MD")
+                LastMD = Args[Idx + 1];
+            }
+            --Idx;
+          }
+        }
+        // If there's no -MT/-MQ Driver would add -MT with the value of the last
+        // -o option.
         tooling::CommandLineArguments AdjustedArgs = Args;
         AdjustedArgs.push_back("-o");
         AdjustedArgs.push_back("/dev/null");
+        if (LastMT.empty() && LastMQ.empty()) {
+          AdjustedArgs.push_back("-MT");
+          // We're interested in source dependencies of an object file.
+          if (LastMD.empty()) {
+            // FIXME: We are missing the directory unless the -o value is an
+            // absolute path.
+            AdjustedArgs.push_back(!LastO.empty() ? LastO
+                                                  : getObjFilePath(FileName));
+          } else {
+            AdjustedArgs.push_back(FileName);
+          }
+        }
         AdjustedArgs.push_back("-Xclang");
         AdjustedArgs.push_back("-Eonly");
         AdjustedArgs.push_back("-Xclang");
         AdjustedArgs.push_back("-sys-header-deps");
         AdjustedArgs.push_back("-Wno-error");
         return AdjustedArgs;
       });