[clang] 2f3bb76 - [clang][DependencyScanning] Reset options generated for named module compilations. (#161486)
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Mon Oct 6 10:11:56 PDT 2025
Author: Naveen Seth Hanig
Date: 2025-10-06T19:11:52+02:00
New Revision: 2f3bb7678182182e47b0ab5e23fa09edaa390414
URL: https://github.com/llvm/llvm-project/commit/2f3bb7678182182e47b0ab5e23fa09edaa390414
DIFF: https://github.com/llvm/llvm-project/commit/2f3bb7678182182e47b0ab5e23fa09edaa390414.diff
LOG: [clang][DependencyScanning] Reset options generated for named module compilations. (#161486)
The driver-generated -cc1 command-lines for C++ named module inputs
introduce some command-line options which affect the canonical module
build command (and therefore the context hash).
This resets those options.
Added:
clang/test/ClangScanDeps/modules-context-hash-from-named-module.cpp
Modified:
clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
Removed:
################################################################################
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
index e1f4d0d361185..b0096d8e6b08b 100644
--- a/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
@@ -509,6 +509,8 @@ bool initializeScanCompilerInstance(
ScanInstance.getFrontendOpts().DisableFree = false;
ScanInstance.getFrontendOpts().GenerateGlobalModuleIndex = false;
ScanInstance.getFrontendOpts().UseGlobalModuleIndex = false;
+ ScanInstance.getFrontendOpts().GenReducedBMI = false;
+ ScanInstance.getFrontendOpts().ModuleOutputPath.clear();
// This will prevent us compiling individual modules asynchronously since
// FileManager is not thread-safe, but it does improve performance for now.
ScanInstance.getFrontendOpts().ModulesShareFileManager = true;
diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
index d67178c153e88..a117bec0d656e 100644
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -263,6 +263,10 @@ makeCommonInvocationForModuleBuild(CompilerInvocation CI) {
// units.
CI.getFrontendOpts().Inputs.clear();
CI.getFrontendOpts().OutputFile.clear();
+ CI.getFrontendOpts().GenReducedBMI = false;
+ CI.getFrontendOpts().ModuleOutputPath.clear();
+ CI.getHeaderSearchOpts().ModulesSkipHeaderSearchPaths = false;
+ CI.getHeaderSearchOpts().ModulesSkipDiagnosticOptions = false;
// LLVM options are not going to affect the AST
CI.getFrontendOpts().LLVMArgs.clear();
diff --git a/clang/test/ClangScanDeps/modules-context-hash-from-named-module.cpp b/clang/test/ClangScanDeps/modules-context-hash-from-named-module.cpp
new file mode 100644
index 0000000000000..c27202234f4c5
--- /dev/null
+++ b/clang/test/ClangScanDeps/modules-context-hash-from-named-module.cpp
@@ -0,0 +1,121 @@
+// Checks that driver-generated options for C++ module inputs preserve the
+// canonical module build commands compared to an equivalent non-module input,
+// and that they do not produce additional internal scanning PCMs.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+//--- main.cpp
+#include "root.h"
+import A;
+import B;
+
+auto main() -> int { return 1; }
+
+//--- A.cppm
+module;
+#include "root.h"
+export module A;
+
+//--- B.cppm
+module;
+#include "root.h"
+export module B;
+
+//--- module.modulemap
+module root { header "root.h" }
+
+//--- root.h
+// empty
+
+// RUN: %clang -std=c++23 -fmodules \
+// RUN: -fmodules-cache-path=%t/modules-cache \
+// RUN: %t/main.cpp %t/A.cppm %t/B.cppm \
+// RUN: -fsyntax-only -fdriver-only -MJ %t/deps.json
+//
+// RUN: sed -e '1s/^/[/' -e '$s/,$/]/' -e 's:\\\\\?:/:g' %t/deps.json \
+// RUN: > %t/compile_commands.json
+//
+// RUN: clang-scan-deps \
+// RUN: -compilation-database=%t/compile_commands.json \
+// RUN: -format experimental-full \
+// RUN: | sed 's:\\\\\?:/:g' | FileCheck %s -DPREFIX=%/t
+
+// CHECK: {
+// CHECK-NEXT: "modules": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang-module-deps": [],
+// CHECK-NEXT: "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK: "context-hash": "[[HASH_ROOT:.*]]",
+// CHECK-NEXT: "file-deps": [
+// CHECK-NEXT: "[[PREFIX]]/module.modulemap",
+// CHECK-NEXT: "[[PREFIX]]/root.h"
+// CHECK-NEXT: ],
+// CHECK-NEXT: "link-libraries": [],
+// CHECK-NEXT: "name": "root"
+// CHECK-NEXT: }
+// CHECK-NEXT: ],
+// CHECK-NEXT: "translation-units": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "commands": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang-context-hash": "{{.*}}",
+// CHECK-NEXT: "named-module-deps": [
+// CHECK-NEXT: "A",
+// CHECK-NEXT: "B"
+// CHECK-NEXT: ],
+// CHECK-NEXT: "clang-module-deps": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "context-hash": "[[HASH_ROOT]]",
+// CHECK-NEXT: "module-name": "root"
+// CHECK-NEXT: }
+// CHECK-NEXT: ],
+// CHECK: "file-deps": [
+// CHECK-NEXT: "[[PREFIX]]/main.cpp"
+// CHECK-NEXT: ],
+// CHECK-NEXT: "input-file": "[[PREFIX]]/main.cpp"
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+// CHECK-NEXT: },
+// CHECK-NEXT: {
+// CHECK-NEXT: "commands": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang-context-hash": "{{.*}}",
+// CHECK-NEXT: "named-module": "A",
+// CHECK-NEXT: "clang-module-deps": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "context-hash": "[[HASH_ROOT]]",
+// CHECK-NEXT: "module-name": "root"
+// CHECK-NEXT: }
+// CHECK-NEXT: ],
+// CHECK: "file-deps": [
+// CHECK-NEXT: "[[PREFIX]]/A.cppm"
+// CHECK-NEXT: ],
+// CHECK-NEXT: "input-file": "[[PREFIX]]/A.cppm"
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+// CHECK-NEXT: },
+// CHECK-NEXT: {
+// CHECK-NEXT: "commands": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang-context-hash": "{{.*}}",
+// CHECK-NEXT: "named-module": "B",
+// CHECK-NEXT: "clang-module-deps": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "context-hash": "[[HASH_ROOT]]",
+// CHECK-NEXT: "module-name": "root"
+// CHECK-NEXT: }
+// CHECK-NEXT: ],
+// CHECK: "file-deps": [
+// CHECK-NEXT: "[[PREFIX]]/B.cppm"
+// CHECK-NEXT: ],
+// CHECK-NEXT: "input-file": "[[PREFIX]]/B.cppm"
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+// CHECK-NEXT: }
+
+// This tests that the scanner doesn't produce multiple internal scanning PCMs
+// for our single Clang module (root).
+// RUN: find %t/modules-cache -name "*.pcm" | wc -l | grep 1
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