[libclang][cas] Optionally enable include-tree in libclang dependency scanner

Obey CLANG_CACHE_USE_INCLUDE_TREE and CLANG_CACHE_USE_CASFS_DEPSCAN. For
now the default is still cas-fs since that supports modules and
include-tree does not.

(cherry picked from commit 72a7cc4)

Author: benlangmuir

clang/test/Index/Core/scan-deps-cas.m

@@ -1,11 +1,22 @@
 // RUN: rm -rf %t.mcp %t
-// RUN: echo %S > %t.result
-//
+
 // RUN: c-index-test core --scan-deps %S -output-dir=%t -cas-path %t/cas \
 // RUN:  -- %clang -c -I %S/Inputs/module \
 // RUN:     -fmodules -fmodules-cache-path=%t.mcp \
-// RUN:     -o FoE.o -x objective-c %s >> %t.result
-// RUN: cat %t.result | sed 's/\\/\//g' | FileCheck %s -DOUTPUTS=%/t
+// RUN:     -o FoE.o -x objective-c %s > %t.result
+// RUN: cat %t.result | sed 's/\\/\//g' | FileCheck %s -DPREFIX=%S -DOUTPUTS=%/t
+
+// RUN: env CLANG_CACHE_USE_CASFS_DEPSCAN=1 c-index-test core --scan-deps %S -output-dir=%t -cas-path %t/cas \
+// RUN:  -- %clang -c -I %S/Inputs/module \
+// RUN:     -fmodules -fmodules-cache-path=%t.mcp \
+// RUN:     -o FoE.o -x objective-c %s > %t.casfs.result
+// RUN: cat %t.casfs.result | sed 's/\\/\//g' | FileCheck %s -DPREFIX=%S -DOUTPUTS=%/t
+
+// FIXME: enable modules when supported.
+// RUN: env CLANG_CACHE_USE_INCLUDE_TREE=1 c-index-test core --scan-deps %S -output-dir=%t -cas-path %t/cas \
+// RUN:  -- %clang -c -I %S/Inputs/module \
+// RUN:     -o FoE.o -x objective-c %s > %t.includetree.result
+// RUN: cat %t.includetree.result | sed 's/\\/\//g' | FileCheck %s -DPREFIX=%S -DOUTPUTS=%/t -check-prefix=INCLUDE_TREE
 
 // RUN: c-index-test core --scan-deps %S -output-dir=%t \
 // RUN:  -- %clang -c -I %S/Inputs/module \
@@ -15,10 +26,9 @@
 // NO_CAS-NOT: faction-cache
 // NO_CAS-NOT: fcache-compile-job
 
-@import ModA;
+#include "ModA.h"
 
-// CHECK: [[PREFIX:.*]]
-// CHECK-NEXT: modules:
+// CHECK:       modules:
 // CHECK-NEXT:   module:
 // CHECK-NEXT:     name: ModA
 // CHECK-NEXT:     context-hash: [[HASH_MOD_A:[A-Z0-9]+]]
@@ -52,3 +62,16 @@
 // CHECK-SAME:       -fcache-compile-job
 // CHECK-SAME:       -fmodule-file-cache-key [[PCM:.*ModA_.*pcm]] llvmcas://{{[[:xdigit:]]+}}
 // CHECK-SAME:       -fmodule-file={{(ModA=)?}}[[PCM]]
+
+// INCLUDE_TREE:      dependencies:
+// INCLUDE_TREE-NEXT:   command 0:
+// INCLUDE_TREE-NEXT:     context-hash: [[HASH_TU:[A-Z0-9]+]]
+// INCLUDE_TREE-NEXT:     module-deps:
+// INCLUDE_TREE-NEXT:     file-deps:
+// INCLUDE_TREE-NEXT:       [[PREFIX]]/scan-deps-cas.m
+// INCLUDE_TREE-NEXT:       [[PREFIX]]/Inputs/module/ModA.h
+// INCLUDE_TREE-NEXT:     build-args:
+// INCLUDE_TREE-SAME:       -cc1
+// INCLUDE_TREE-SAME:       -fcas-path
+// INCLUDE_TREE-SAME:       -fcas-include-tree llvmcas://{{[[:xdigit:]]+}}
+// INCLUDE_TREE-SAME:       -fcache-compile-job

clang/tools/libclang/CDependencies.cpp

@@ -22,16 +22,19 @@
 #include "clang/Tooling/DependencyScanning/DependencyScanningTool.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningWorker.h"
 #include "llvm/CAS/CachingOnDiskFileSystem.h"
+#include "llvm/Support/Process.h"
 
 using namespace clang;
 using namespace clang::tooling::dependencies;
 
 namespace {
 struct DependencyScannerServiceOptions {
-  ScanningOutputFormat Format = ScanningOutputFormat::Full;
+  ScanningOutputFormat ConfiguredFormat = ScanningOutputFormat::Full;
   CASOptions CASOpts;
   std::shared_ptr<cas::ObjectStore> CAS;
   std::shared_ptr<cas::ActionCache> Cache;
+
+  ScanningOutputFormat getFormat() const;
 };
 } // end anonymous namespace
 
@@ -93,7 +96,7 @@ void clang_experimental_DependencyScannerServiceOptions_dispose(
 
 void clang_experimental_DependencyScannerServiceOptions_setDependencyMode(
     CXDependencyScannerServiceOptions Opts, CXDependencyMode Mode) {
-  unwrap(Opts)->Format = unwrap(Mode);
+  unwrap(Opts)->ConfiguredFormat = unwrap(Mode);
 }
 
 void clang_experimental_DependencyScannerServiceOptions_setCASDatabases(
@@ -122,10 +125,27 @@ clang_experimental_DependencyScannerService_create_v0(CXDependencyMode Format) {
   IntrusiveRefCntPtr<llvm::cas::CachingOnDiskFileSystem> FS;
   return wrap(new DependencyScanningService(
       ScanningMode::DependencyDirectivesScan, unwrap(Format), CASOpts,
-      /*ActionCache=*/nullptr, FS,
+      /*CAS=*/nullptr, /*ActionCache=*/nullptr, FS,
       /*ReuseFilemanager=*/false));
 }
 
+ScanningOutputFormat DependencyScannerServiceOptions::getFormat() const {
+  if (ConfiguredFormat != ScanningOutputFormat::Full)
+    return ConfiguredFormat;
+
+  if (!CAS || !Cache)
+    return ConfiguredFormat;
+
+  if (llvm::sys::Process::GetEnv("CLANG_CACHE_USE_INCLUDE_TREE"))
+    return ScanningOutputFormat::FullIncludeTree;
+
+  if (llvm::sys::Process::GetEnv("CLANG_CACHE_USE_CASFS_DEPSCAN"))
+    return ScanningOutputFormat::FullTree;
+
+  // Note: default caching behaviour is currently cas-fs.
+  return ConfiguredFormat;
+}
+
 CXDependencyScannerService
 clang_experimental_DependencyScannerService_create_v1(
     CXDependencyScannerServiceOptions Opts) {
@@ -137,11 +157,11 @@ clang_experimental_DependencyScannerService_create_v1(
     assert(unwrap(Opts)->CASOpts.getKind() != CASOptions::UnknownCAS &&
            "CAS and ActionCache must match CASOptions");
     FS = llvm::cantFail(
-        llvm::cas::createCachingOnDiskFileSystem(std::move(CAS)));
+        llvm::cas::createCachingOnDiskFileSystem(CAS));
   }
   return wrap(new DependencyScanningService(
-      ScanningMode::DependencyDirectivesScan, unwrap(Opts)->Format,
-      unwrap(Opts)->CASOpts, std::move(Cache), std::move(FS),
+      ScanningMode::DependencyDirectivesScan, unwrap(Opts)->getFormat(),
+      unwrap(Opts)->CASOpts, std::move(CAS), std::move(Cache), std::move(FS),
       /*ReuseFilemanager=*/false));
 }
 
@@ -257,7 +277,9 @@ static CXErrorCode getFileDependencies(CXDependencyScannerWorker W, int argc,
 
   DependencyScanningWorker *Worker = unwrap(W);
 
-  if (Worker->getScanningFormat() != ScanningOutputFormat::Full)
+  if (Worker->getScanningFormat() != ScanningOutputFormat::Full &&
+      Worker->getScanningFormat() != ScanningOutputFormat::FullTree &&
+      Worker->getScanningFormat() != ScanningOutputFormat::FullIncludeTree)
     return CXError_InvalidArguments;
 
   std::vector<std::string> Compilation{argv, argv + argc};