[clang] [clang-scan-deps] [P1689] Keep consistent behavior for make dependencies with clang (PR #69551)

[Chuanqi Xu via cfe-commits]

https://github.com/ChuanqiXu9 created https://github.com/llvm/llvm-project/pull/69551

Close https://github.com/llvm/llvm-project/issues/69439.

This patch tries to reuse the codes to generate make style dependencies information with P1689 format directly.

>From 17b84659fa91d8a92a3d41aad8fbc3fa587a89b9 Mon Sep 17 00:00:00 2001
From: Chuanqi Xu <yedeng.yd at linux.alibaba.com>
Date: Thu, 19 Oct 2023 10:04:25 +0800
Subject: [PATCH] [clang-scan-deps] [P1689] Keep consistent behavior for make
 dependencies with clang

Close https://github.com/llvm/llvm-project/issues/69439.

This patch tries to reuse the codes to generate make style dependencies
information with P1689 format directly.
---
 .../DependencyScanning/DependencyScanningWorker.cpp  |  8 ++++++--
 .../DependencyScanning/ModuleDepCollector.cpp        | 12 +++++++++---
 clang/test/ClangScanDeps/P1689.cppm                  | 10 ++++++++++
 3 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
index 29df0c3a0afdb5c..b7911f9844a3554 100644
--- a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
@@ -231,12 +231,16 @@ class DependencyScanningAction : public tooling::ToolAction {
     Opts->IncludeSystemHeaders = true;
 
     switch (Format) {
+    case ScanningOutputFormat::P1689:
     case ScanningOutputFormat::Make:
       ScanInstance.addDependencyCollector(
           std::make_shared<DependencyConsumerForwarder>(
               std::move(Opts), WorkingDirectory, Consumer));
-      break;
-    case ScanningOutputFormat::P1689:
+
+      if (Format == ScanningOutputFormat::Make)
+        break;
+
+      [[fallthrough]];
     case ScanningOutputFormat::Full:
       MDC = std::make_shared<ModuleDepCollector>(
           std::move(Opts), ScanInstance, Consumer, Controller,
diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
index 40115b7b5ae25b3..ea42923f9545d97 100644
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -436,7 +436,10 @@ void ModuleDepCollectorPP::EndOfMainFile() {
   for (const Module *M : MDC.DirectModularDeps)
     handleTopLevelModule(M);
 
-  MDC.Consumer.handleDependencyOutputOpts(*MDC.Opts);
+  // With P1689 format, we get the output options from
+  // DependencyConsumerForwarder.
+  if (!MDC.IsStdModuleP1689Format)
+    MDC.Consumer.handleDependencyOutputOpts(*MDC.Opts);
 
   if (MDC.IsStdModuleP1689Format)
     MDC.Consumer.handleProvidedAndRequiredStdCXXModules(
@@ -452,8 +455,11 @@ void ModuleDepCollectorPP::EndOfMainFile() {
       MDC.Consumer.handleDirectModuleDependency(MDC.ModularDeps[M]->ID);
   }
 
-  for (auto &&I : MDC.FileDeps)
-    MDC.Consumer.handleFileDependency(I);
+  // With P1689 format, we collect the file dependencies from make's dep
+  // collector.
+  if (!MDC.IsStdModuleP1689Format)
+    for (auto &&I : MDC.FileDeps)
+      MDC.Consumer.handleFileDependency(I);
 
   for (auto &&I : MDC.DirectPrebuiltModularDeps)
     MDC.Consumer.handlePrebuiltModuleDependency(I.second);
diff --git a/clang/test/ClangScanDeps/P1689.cppm b/clang/test/ClangScanDeps/P1689.cppm
index dffb16974a3e4e4..b992502a5179c15 100644
--- a/clang/test/ClangScanDeps/P1689.cppm
+++ b/clang/test/ClangScanDeps/P1689.cppm
@@ -42,6 +42,14 @@
 // RUN: clang-scan-deps -format=p1689 \
 // RUN:   -- %clang++ -std=c++20 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache -c %t/impl_part.cppm -o %t/impl_part.o \
 // RUN:   | FileCheck %t/impl_part.cppm -DPREFIX=%/t
+//
+// Check the path in the make style dependencies are generated in relative path form
+// RUN: cd %t
+// RUN: clang-scan-deps -format=p1689 \
+// RUN:   -- %clang++ -std=c++20 -c -fprebuilt-module-path=%t impl_part.cppm -o impl_part.o \
+// RUN:      -MT impl_part.o.ddi -MD -MF impl_part.dep
+// RUN:   cat impl_part.dep | FileCheck impl_part.cppm -DPREFIX=%/t --check-prefix=CHECK-MAKE-RELATIVE
+
 
 //--- P1689.json.in
 [
@@ -168,6 +176,8 @@ void World() {
 // CHECK-MAKE:   [[PREFIX]]/impl_part.cppm
 // CHECK-MAKE:   [[PREFIX]]/header.mock
 
+// CHECK-MAKE-RELATIVE: impl_part.o.ddi: ./impl_part.cppm ./header.mock
+
 //--- interface_part.cppm
 export module M:interface_part;
 export void World();