[clang-scan-deps] Infer the tool locations from PATH

clang/include/clang/Tooling/CompilationDatabase.h

@@ -234,6 +234,12 @@ std::unique_ptr<CompilationDatabase>
 std::unique_ptr<CompilationDatabase>
 inferTargetAndDriverMode(std::unique_ptr<CompilationDatabase> Base);
 
+/// Returns a wrapped CompilationDatabase that will transform argv[0] to an
+/// absolute path, if it currently is a plain tool name, looking it up in
+/// PATH.
+std::unique_ptr<CompilationDatabase>
+inferToolLocation(std::unique_ptr<CompilationDatabase> Base);
+
 /// Returns a wrapped CompilationDatabase that will expand all rsp(response)
 /// files on commandline returned by underlying database.
 std::unique_ptr<CompilationDatabase>

clang/lib/Tooling/CMakeLists.txt

@@ -25,6 +25,7 @@ add_clang_library(clangTooling
   GuessTargetAndModeCompilationDatabase.cpp
   InterpolatingCompilationDatabase.cpp
   JSONCompilationDatabase.cpp
+  LocateToolCompilationDatabase.cpp
   Refactoring.cpp
   RefactoringCallbacks.cpp
   StandaloneExecution.cpp

clang/lib/Tooling/LocateToolCompilationDatabase.cpp

@@ -0,0 +1,71 @@
+//===- GuessTargetAndModeCompilationDatabase.cpp --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/CompilationDatabase.h"
+#include "clang/Tooling/Tooling.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Program.h"
+#include <memory>
+
+namespace clang {
+namespace tooling {
+
+namespace {
+class LocationAdderDatabase : public CompilationDatabase {
+public:
+  LocationAdderDatabase(std::unique_ptr<CompilationDatabase> Base)
+      : Base(std::move(Base)) {
+    assert(this->Base != nullptr);
+  }
+
+  std::vector<std::string> getAllFiles() const override {
+    return Base->getAllFiles();
+  }
+
+  std::vector<CompileCommand> getAllCompileCommands() const override {
+    return addLocation(Base->getAllCompileCommands());
+  }
+
+  std::vector<CompileCommand>
+  getCompileCommands(StringRef FilePath) const override {
+    return addLocation(Base->getCompileCommands(FilePath));
+  }
+
+private:
+  std::vector<CompileCommand>
+  addLocation(std::vector<CompileCommand> Cmds) const {
+    for (auto &Cmd : Cmds) {
+      if (Cmd.CommandLine.empty())
+        continue;
+      std::string &Driver = Cmd.CommandLine.front();
+      // If the driver name already is absolute, we don't need to do anything.
+      if (llvm::sys::path::is_absolute(Driver))
+        continue;
+      // If the name is a relative path, like bin/clang, we assume it's
+      // possible to resolve it and don't do anything about it either.
+      if (llvm::any_of(Driver,
+                       [](char C) { return llvm::sys::path::is_separator(C); }))
+        continue;
+      auto Absolute = llvm::sys::findProgramByName(Driver);
+      // If we found it in path, update the entry in Cmd.CommandLine
+      if (Absolute && llvm::sys::path::is_absolute(*Absolute))
+        Driver = std::move(*Absolute);
+    }
+    return Cmds;
+  }
+  std::unique_ptr<CompilationDatabase> Base;
+};
+} // namespace
+
+std::unique_ptr<CompilationDatabase>
+inferToolLocation(std::unique_ptr<CompilationDatabase> Base) {
+  return std::make_unique<LocationAdderDatabase>(std::move(Base));
+}
+
+} // namespace tooling
+} // namespace clang

clang/test/ClangScanDeps/modules-extern-submodule.c

@@ -112,7 +112,7 @@ module third {}
 // CHECK:                  "-fmodule-map-file=[[PREFIX]]/first/first/module.modulemap",
 // CHECK:                  "-fmodule-file=first=[[PREFIX]]/cache/{{.*}}/first-{{.*}}.pcm",
 // CHECK:                ],
-// CHECK-NEXT:           "executable": "clang",
+// CHECK-NEXT:           "executable": "{{.*}}clang",
 // CHECK-NEXT:           "file-deps": [
 // CHECK-NEXT:             "[[PREFIX]]/tu.m"
 // CHECK-NEXT:           ],

clang/test/ClangScanDeps/modules-full-output-tu-order.c

@@ -35,7 +35,7 @@
 // CHECK:                  "-D"
 // CHECK-NEXT:             "ONE"
 // CHECK:                ],
-// CHECK-NEXT:           "executable": "clang",
+// CHECK-NEXT:           "executable": "{{.*}}clang",
 // CHECK-NEXT:           "file-deps": [
 // CHECK-NEXT:             "[[PREFIX]]/tu.c"
 // CHECK-NEXT:           ],
@@ -52,7 +52,7 @@
 // CHECK:                  "-D"
 // CHECK-NEXT:             "TWO"
 // CHECK:                ],
-// CHECK-NEXT:           "executable": "clang",
+// CHECK-NEXT:           "executable": "{{.*}}clang",
 // CHECK-NEXT:           "file-deps": [
 // CHECK-NEXT:             "[[PREFIX]]/tu.c"
 // CHECK-NEXT:           ],

clang/test/ClangScanDeps/modules-has-include-umbrella-header.c

@@ -64,7 +64,7 @@ module Dependency { header "dependency.h" }
 // CHECK:                ],
 // CHECK-NEXT:           "command-line": [
 // CHECK:                ],
-// CHECK-NEXT:           "executable": "clang",
+// CHECK-NEXT:           "executable": "{{.*}}clang",
 // CHECK-NEXT:           "file-deps": [
 // CHECK-NEXT:             "[[PREFIX]]/tu.c"
 // CHECK-NEXT:           ],

clang/test/ClangScanDeps/modules-header-sharing.m

@@ -77,7 +77,7 @@
 // CHECK:                  "-fmodule-map-file=[[PREFIX]]/frameworks/A.framework/Modules/module.modulemap",
 // CHECK:                  "-fmodule-name=A",
 // CHECK:                ],
-// CHECK-NEXT:           "executable": "clang",
+// CHECK-NEXT:           "executable": "{{.*}}clang",
 // CHECK-NEXT:           "file-deps": [
 // CHECK-NEXT:             "[[PREFIX]]/tu.m",
 // CHECK-NEXT:             "[[PREFIX]]/shared/H.h"

clang/test/ClangScanDeps/modules-implementation-module-map.c

@@ -27,7 +27,7 @@ framework module FWPrivate { header "private.h" }
 // CHECK:                "-fmodule-map-file=[[PREFIX]]/frameworks/FW.framework/Modules/module.private.modulemap",
 // CHECK:                "-fmodule-name=FWPrivate",
 // CHECK:              ],
-// CHECK-NEXT:         "executable": "clang",
+// CHECK-NEXT:         "executable": "{{.*}}clang",
 // CHECK-NEXT:         "file-deps": [
 // CHECK-NEXT:           "[[PREFIX]]/tu.m"
 // CHECK-NEXT:         ],

clang/test/ClangScanDeps/modules-implementation-private.m

@@ -62,7 +62,7 @@
 // CHECK-NEXT:           ],
 // CHECK-NEXT:           "command-line": [
 // CHECK:                ],
-// CHECK-NEXT:           "executable": "clang",
+// CHECK-NEXT:           "executable": "{{.*}}clang",
 // CHECK-NEXT:           "file-deps": [
 // CHECK-NEXT:             "[[PREFIX]]/tu.m",
 // CHECK-NEXT:             "[[PREFIX]]/frameworks/FW.framework/PrivateHeaders/Missed.h",

clang/test/ClangScanDeps/modules-priv-fw-from-pub.m

@@ -110,7 +110,7 @@
 // CHECK-NEXT:           ],
 // CHECK-NEXT:           "command-line": [
 // CHECK:                ],
-// CHECK-NEXT:           "executable": "clang",
+// CHECK-NEXT:           "executable": "{{.*}}clang",
 // CHECK-NEXT:           "file-deps": [
 // CHECK-NEXT:             "[[PREFIX]]/tu.m"
 // CHECK-NEXT:           ],

clang/test/ClangScanDeps/resolve-executable-path.c

@@ -0,0 +1,32 @@
+// UNSUPPORTED: system-windows
+
+// Check that we expand the executable name to an absolute path, when invoked
+// with a plain executable name, which is implied to be found in PATH.
+// REQUIRES: x86-registered-target
+
+// RUN: rm -rf %t
+// RUN: mkdir -p %t/bin
+// RUN: ln -s %clang %t/bin/x86_64-w64-mingw32-clang
+// RUN: split-file %s %t
+// RUN: sed -e "s|DIR|%/t|g" %t/cdb.json.in > %t/cdb.json
+
+// Check that we can deduce this both when using a compilation database, and when using
+// a literal command line.
+
+// RUN: env "PATH=%t/bin:%PATH%" clang-scan-deps -format experimental-full -compilation-database %t/cdb.json | FileCheck %s -DBASE=%/t
+
+// RUN: env "PATH=%t/bin:%PATH%" clang-scan-deps -format experimental-full -- x86_64-w64-mingw32-clang %t/source.c -o %t/source.o | FileCheck %s -DBASE=%/t
+
+// CHECK: "executable": "[[BASE]]/bin/x86_64-w64-mingw32-clang"
+
+//--- cdb.json.in
+[
+  {
+    "directory": "DIR"
+    "command": "x86_64-w64-mingw32-clang -c DIR/source.c -o DIR/source.o"
+    "file": "DIR/source.c"
+  },
+]
+
+//--- source.c
+void func(void) {}

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

@@ -815,6 +815,8 @@ int clang_scan_deps_main(int argc, char **argv, const llvm::ToolContext &) {
 
   Compilations = inferTargetAndDriverMode(std::move(Compilations));
 
+  Compilations = inferToolLocation(std::move(Compilations));
+
   // The command options are rewritten to run Clang in preprocessor only mode.
   auto AdjustingCompilations =
       std::make_unique<tooling::ArgumentsAdjustingCompilations>(