[clang][deps][cas] Perform prefix mapping inside FullDependencyConsumer

This makes FullDependencyConsumer behave more like the include-tree
consumer, which does prefix mapping internally rather than via callback.
This is in preparation for expanding the availability of prefix mapping
to all users of the FullDependenciesConsumer rather than only in
ScanAndUpdateArgs.

Note: there is some duplication of prefix mappers in scanAndUpdateArgs
because it is prefix-mapping a different CompilerInvocation than the one
that is inside the consumer. That duplication is the same for the
existing include-tree code path.

(cherry picked from commit aea1b44)

Author: benlangmuir

clang/include/clang/Tooling/DependencyScanning/DependencyScanningTool.h

@@ -12,11 +12,14 @@
 #include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningWorker.h"
 #include "clang/Tooling/DependencyScanning/ModuleDepCollector.h"
+#include "clang/Tooling/DependencyScanning/ScanAndUpdateArgs.h"
 #include "clang/Tooling/JSONCompilationDatabase.h"
 #include "llvm/ADT/MapVector.h"
-#include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/CAS/CASID.h"
+#include "llvm/Support/PrefixMapper.h"
+#include <optional>
 #include <string>
 #include <vector>
 
@@ -33,8 +36,6 @@ class IncludeTreeRoot;
 namespace tooling {
 namespace dependencies {
 
-struct DepscanPrefixMapping;
-
 /// A callback to lookup module outputs for "-fmodule-file=", "-o" etc.
 using LookupModuleOutputCallback =
     llvm::function_ref<std::string(const ModuleID &, ModuleOutputKind)>;
@@ -81,8 +82,6 @@ struct FullDependenciesResult {
   std::vector<ModuleDeps> DiscoveredModules;
 };
 
-using RemapPathCallback = llvm::cas::CachingOnDiskFileSystem::RemapPathCallback;
-
 /// The high-level implementation of the dependency discovery tool that runs on
 /// an individual worker thread.
 class DependencyScanningTool {
@@ -115,7 +114,8 @@ class DependencyScanningTool {
   getDependencyTreeFromCompilerInvocation(
       std::shared_ptr<CompilerInvocation> Invocation, StringRef CWD,
       DiagnosticConsumer &DiagsConsumer, raw_ostream *VerboseOS,
-      bool DiagGenerationAsCompilation, RemapPathCallback RemapPath = nullptr);
+      bool DiagGenerationAsCompilation,
+      DepscanPrefixMapping PrefixMapping = {});
 
   Expected<cas::IncludeTreeRoot>
   getIncludeTree(cas::ObjectStore &DB,
@@ -186,8 +186,8 @@ class FullDependencyConsumer : public DependencyConsumer {
                          LookupModuleOutputCallback LookupModuleOutput,
                          bool EagerLoadModules,
                          CachingOnDiskFileSystemPtr CacheFS = nullptr,
-                         RemapPathCallback RemapPath = nullptr)
-      : CacheFS(std::move(CacheFS)), RemapPath(RemapPath),
+                         DepscanPrefixMapping PrefixMapping = {})
+      : CacheFS(std::move(CacheFS)), PrefixMapping(std::move(PrefixMapping)),
         AlreadySeen(AlreadySeen), LookupModuleOutput(LookupModuleOutput),
         EagerLoadModules(EagerLoadModules) {}
 
@@ -250,7 +250,8 @@ class FullDependencyConsumer : public DependencyConsumer {
   std::vector<Command> Commands;
   std::string ContextHash;
   CachingOnDiskFileSystemPtr CacheFS;
-  RemapPathCallback RemapPath;
+  DepscanPrefixMapping PrefixMapping;
+  std::optional<llvm::TreePathPrefixMapper> Mapper;
   CASOptions CASOpts;
   Optional<cas::CASID> CASFileSystemRootID;
   std::vector<std::string> OutputPaths;

clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp

@@ -143,9 +143,9 @@ class GetDependencyTree : public FullDependencyConsumer {
   }
 
   GetDependencyTree(llvm::cas::CachingOnDiskFileSystem &FS,
-                    RemapPathCallback RemapPath)
+                    DepscanPrefixMapping PrefixMapping)
       : FullDependencyConsumer(AlreadySeen, nullptr, /*EagerModules=*/false,
-                               &FS, RemapPath),
+                               &FS, std::move(PrefixMapping)),
         FS(FS) {}
 
 private:
@@ -157,7 +157,7 @@ class GetDependencyTree : public FullDependencyConsumer {
 llvm::Expected<llvm::cas::ObjectProxy>
 DependencyScanningTool::getDependencyTree(
     const std::vector<std::string> &CommandLine, StringRef CWD) {
-  GetDependencyTree Consumer(*Worker.getCASFS(), /*RemapPath=*/nullptr);
+  GetDependencyTree Consumer(*Worker.getCASFS(), /*PrefixMapping=*/{});
   auto Result = Worker.computeDependencies(CWD, CommandLine, Consumer);
   if (Result)
     return std::move(Result);
@@ -168,8 +168,8 @@ llvm::Expected<llvm::cas::ObjectProxy>
 DependencyScanningTool::getDependencyTreeFromCompilerInvocation(
     std::shared_ptr<CompilerInvocation> Invocation, StringRef CWD,
     DiagnosticConsumer &DiagsConsumer, raw_ostream *VerboseOS,
-    bool DiagGenerationAsCompilation, RemapPathCallback RemapPath) {
-  GetDependencyTree Consumer(*Worker.getCASFS(), RemapPath);
+    bool DiagGenerationAsCompilation, DepscanPrefixMapping PrefixMapping) {
+  GetDependencyTree Consumer(*Worker.getCASFS(), std::move(PrefixMapping));
   Worker.computeDependenciesFromCompilerInvocation(
       std::move(Invocation), CWD, Consumer, DiagsConsumer, VerboseOS,
       DiagGenerationAsCompilation);
@@ -588,6 +588,11 @@ DependencyScanningTool::getFullDependenciesLegacyDriverCommand(
 Error FullDependencyConsumer::initialize(CompilerInstance &ScanInstance,
                                          CompilerInvocation &NewInvocation) {
   if (CacheFS) {
+    // Setup prefix mapping.
+    Mapper.emplace(CacheFS);
+    if (Error E = PrefixMapping.configurePrefixMapper(NewInvocation, *Mapper))
+      return E;
+
     CacheFS->trackNewAccesses();
     if (auto CWD =
             ScanInstance.getVirtualFileSystem().getCurrentWorkingDirectory())
@@ -617,8 +622,14 @@ Error FullDependencyConsumer::finalize(CompilerInstance &ScanInstance,
     (void)CacheFS->status(NewInvocation.getCodeGenOpts().SampleProfileFile);
     (void)CacheFS->status(NewInvocation.getCodeGenOpts().ProfileRemappingFile);
 
-    if (auto E = CacheFS->createTreeFromNewAccesses(RemapPath).moveInto(
-            CASFileSystemRootID))
+    auto E = CacheFS
+                 ->createTreeFromNewAccesses(
+                     [&](const llvm::vfs::CachedDirectoryEntry &Entry,
+                         SmallVectorImpl<char> &Storage) {
+                       return Mapper->mapDirEntry(Entry, Storage);
+                     })
+                 .moveInto(CASFileSystemRootID);
+    if (E)
       return E;
 
     configureInvocationForCaching(NewInvocation, CASOpts,
@@ -654,7 +665,14 @@ Error FullDependencyConsumer::finalizeModuleBuild(
     CompilerInstance &ModuleScanInstance) {
   if (CacheFS) {
     std::optional<cas::CASID> RootID;
-    if (auto E = CacheFS->createTreeFromNewAccesses(RemapPath).moveInto(RootID))
+    auto E = CacheFS
+                 ->createTreeFromNewAccesses(
+                     [&](const llvm::vfs::CachedDirectoryEntry &Entry,
+                         SmallVectorImpl<char> &Storage) {
+                       return Mapper->mapDirEntry(Entry, Storage);
+                     })
+                 .moveInto(RootID);
+    if (E)
       return E;
 
     Module *M = ModuleScanInstance.getPreprocessor().getCurrentModule();

clang/lib/Tooling/DependencyScanning/ScanAndUpdateArgs.cpp

@@ -257,17 +257,11 @@ Expected<llvm::cas::CASID> clang::scanAndUpdateCC1InlineWithTool(
                       .moveInto(Root))
       return std::move(E);
   } else {
-    if (Error E =
-            Tool.getDependencyTreeFromCompilerInvocation(
-                    std::move(ScanInvocation), WorkingDirectory, DiagsConsumer,
-                    VerboseOS,
-                    /*DiagGenerationAsCompilation*/ true,
-                    [&](const llvm::vfs::CachedDirectoryEntry &Entry,
-                        SmallVectorImpl<char> &Storage) {
-                      return static_cast<llvm::TreePathPrefixMapper &>(Mapper)
-                          .mapDirEntry(Entry, Storage);
-                    })
-                .moveInto(Root))
+    if (Error E = Tool.getDependencyTreeFromCompilerInvocation(
+                          std::move(ScanInvocation), WorkingDirectory,
+                          DiagsConsumer, VerboseOS,
+                          /*DiagGenerationAsCompilation*/ true, PrefixMapping)
+                      .moveInto(Root))
       return std::move(E);
   }