[clang] [clang][DependencyScanner] Remove all warning flags when suppressing warnings (PR #71612)
Michael Spencer via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 8 17:24:55 PST 2023
https://github.com/Bigcheese updated https://github.com/llvm/llvm-project/pull/71612
>From 6c8c4cde5698a1693ad64a14a156030f249032a6 Mon Sep 17 00:00:00 2001
From: Michael Spencer <bigcheesegs at gmail.com>
Date: Tue, 7 Nov 2023 14:02:38 -1000
Subject: [PATCH 1/2] [clang][DependencyScanner] Remove all warning flags when
suppressing warnings
Since system modules don't emit most warnings, remove the warning
flags to increase module reuse.
---
.../DependencyScanningService.h | 7 +-
.../DependencyScanning/ModuleDepCollector.cpp | 26 ++++++
.../ClangScanDeps/optimize-system-warnings.m | 84 +++++++++++++++++++
clang/tools/clang-scan-deps/ClangScanDeps.cpp | 1 +
4 files changed, 116 insertions(+), 2 deletions(-)
create mode 100644 clang/test/ClangScanDeps/optimize-system-warnings.m
diff --git a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h
index a4a03b88b205175..dcdf1c171f6d731 100644
--- a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h
+++ b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h
@@ -51,8 +51,11 @@ enum class ScanningOptimizations {
/// Remove unused header search paths including header maps.
HeaderSearch = 1,
- LLVM_MARK_AS_BITMASK_ENUM(HeaderSearch),
- All = HeaderSearch,
+ /// Remove warnings from system modules.
+ SystemWarnings = 2,
+
+ LLVM_MARK_AS_BITMASK_ENUM(SystemWarnings),
+ All = HeaderSearch | SystemWarnings,
Default = All
};
diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
index 5d95bb305bc38d8..9099c18391e4d29 100644
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -52,6 +52,28 @@ static void optimizeHeaderSearchOpts(HeaderSearchOptions &Opts,
Opts.UserEntries.push_back(Entries[Idx]);
}
+static void optimizeDiagnosticOpts(DiagnosticOptions &Opts,
+ bool IsSystemModule) {
+ // If this is not a system module or -Wsystem-headers was passed, don't
+ // optimize.
+ if (!IsSystemModule)
+ return;
+ bool Wsystem_headers = false;
+ for (StringRef Opt : Opts.Warnings) {
+ bool isPositive = !Opt.consume_front("no-");
+ if (Opt == "system-headers")
+ Wsystem_headers = isPositive;
+ }
+ if (Wsystem_headers)
+ return;
+
+ // Remove all warning flags. System modules suppress most, but not all,
+ // warnings.
+ Opts.Warnings.clear();
+ Opts.UndefPrefixes.clear();
+ Opts.Remarks.clear();
+}
+
static std::vector<std::string> splitString(std::string S, char Separator) {
SmallVector<StringRef> Segments;
StringRef(S).split(Segments, Separator, /*MaxSplit=*/-1, /*KeepEmpty=*/false);
@@ -532,6 +554,10 @@ ModuleDepCollectorPP::handleTopLevelModule(const Module *M) {
if (any(MDC.OptimizeArgs & ScanningOptimizations::HeaderSearch))
optimizeHeaderSearchOpts(BuildInvocation.getMutHeaderSearchOpts(),
*MDC.ScanInstance.getASTReader(), *MF);
+ if (any(MDC.OptimizeArgs & ScanningOptimizations::SystemWarnings))
+ optimizeDiagnosticOpts(
+ BuildInvocation.getMutDiagnosticOpts(),
+ BuildInvocation.getFrontendOpts().IsSystemModule);
});
MDC.associateWithContextHash(CI, MD);
diff --git a/clang/test/ClangScanDeps/optimize-system-warnings.m b/clang/test/ClangScanDeps/optimize-system-warnings.m
new file mode 100644
index 000000000000000..d61724c6f18fff8
--- /dev/null
+++ b/clang/test/ClangScanDeps/optimize-system-warnings.m
@@ -0,0 +1,84 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: sed -e "s|DIR|%/t|g" %t/build/compile-commands.json.in > %t/build/compile-commands.json
+// RUN: clang-scan-deps -compilation-database %t/build/compile-commands.json \
+// RUN: -j 1 -format experimental-full -optimize-args=system-warnings > %t/deps.db
+// RUN: cat %t/deps.db | sed 's:\\\\\?:/:g' | FileCheck %s -DPREFIX=%/t
+
+// CHECK: {
+// CHECK-NEXT: "modules": [
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang-module-deps": [],
+// CHECK-NEXT: "clang-modulemap-file":
+// CHECK-NEXT: "command-line": [
+// CHECK-NOT: "-W
+// CHECK: ],
+// CHECK-NEXT: "context-hash": "{{.*}}",
+// CHECK-NEXT: "file-deps": [
+// CHECK: ],
+// CHECK-NEXT: "name": "A"
+// CHECK-NEXT: },
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang-module-deps": [],
+// CHECK-NEXT: "clang-modulemap-file":
+// CHECK-NEXT: "command-line": [
+// CHECK-NOT: "-W
+// CHECK: ],
+// CHECK-NEXT: "context-hash": "{{.*}}",
+// CHECK-NEXT: "file-deps": [
+// CHECK: ],
+// CHECK-NEXT: "name": "B"
+// CHECK-NEXT: }
+// CHECK-NEXT: ],
+// CHECK-NEXT: "translation-units": [
+// CHECK: ]
+// CHECK: }
+
+//--- build/compile-commands.json.in
+
+[
+{
+ "directory": "DIR",
+ "command": "clang -c DIR/A.m -isystem modules/A -I modules/B -fmodules -fmodules-cache-path=DIR/module-cache -fimplicit-module-maps",
+ "file": "DIR/A.m"
+},
+{
+ "directory": "DIR",
+ "command": "clang -c DIR/B.m -isystem modules/A -I modules/B -fmodules -fmodules-cache-path=DIR/module-cache -fimplicit-module-maps -Wmaybe-unused",
+ "file": "DIR/B.m"
+}
+]
+
+//--- modules/A/module.modulemap
+
+module A {
+ umbrella header "A.h"
+}
+
+//--- modules/A/A.h
+
+typedef int A_t;
+
+//--- modules/B/module.modulemap
+
+module B [system] {
+ umbrella header "B.h"
+}
+
+//--- modules/B/B.h
+
+typedef int B_t;
+
+//--- A.m
+
+#include <A.h>
+#include <B.h>
+
+A_t a = 0;
+
+//--- B.m
+
+#include <A.h>
+#include <B.h>
+
+A_t b = 0;
diff --git a/clang/tools/clang-scan-deps/ClangScanDeps.cpp b/clang/tools/clang-scan-deps/ClangScanDeps.cpp
index 50631fdf0bc3b75..f11c933d9576565 100644
--- a/clang/tools/clang-scan-deps/ClangScanDeps.cpp
+++ b/clang/tools/clang-scan-deps/ClangScanDeps.cpp
@@ -156,6 +156,7 @@ static void ParseArgs(int argc, char **argv) {
llvm::StringSwitch<std::optional<ScanningOptimizations>>(Arg)
.Case("none", ScanningOptimizations::None)
.Case("header-search", ScanningOptimizations::HeaderSearch)
+ .Case("system-warnings", ScanningOptimizations::SystemWarnings)
.Case("all", ScanningOptimizations::All)
.Default(std::nullopt);
if (!Optimization) {
>From 748c9695d1a8883f6971c97d43d4ba7dd58319cf Mon Sep 17 00:00:00 2001
From: Michael Spencer <bigcheesegs at gmail.com>
Date: Wed, 8 Nov 2023 15:11:45 -1000
Subject: [PATCH 2/2] Add test comments and test of -Wsystem-headers flag.
---
.../ClangScanDeps/optimize-system-warnings.m | 39 +++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/clang/test/ClangScanDeps/optimize-system-warnings.m b/clang/test/ClangScanDeps/optimize-system-warnings.m
index d61724c6f18fff8..0c6e544cc52298e 100644
--- a/clang/test/ClangScanDeps/optimize-system-warnings.m
+++ b/clang/test/ClangScanDeps/optimize-system-warnings.m
@@ -1,3 +1,8 @@
+// This test verifies that system module variants are mergable despite having
+// different warning flags, as most warnings are disabled in system modules.
+// This checks for system modules marked as such both via `-isystem` and
+// `[system]`.
+
// RUN: rm -rf %t
// RUN: split-file %s %t
// RUN: sed -e "s|DIR|%/t|g" %t/build/compile-commands.json.in > %t/build/compile-commands.json
@@ -28,12 +33,25 @@
// CHECK-NEXT: "file-deps": [
// CHECK: ],
// CHECK-NEXT: "name": "B"
+// CHECK-NEXT: },
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang-module-deps": [],
+// CHECK-NEXT: "clang-modulemap-file":
+// CHECK-NEXT: "command-line": [
+// CHECK: "-Wmaybe-unused
+// CHECK: ],
+// CHECK-NEXT: "context-hash": "{{.*}}",
+// CHECK-NEXT: "file-deps": [
+// CHECK: ],
+// CHECK-NEXT: "name": "C"
// CHECK-NEXT: }
// CHECK-NEXT: ],
// CHECK-NEXT: "translation-units": [
// CHECK: ]
// CHECK: }
+// A.m and B.m verify that system modules with different warning flags get
+// merged. C.m verifies that -Wsystem-headers disables the optimization.
//--- build/compile-commands.json.in
[
@@ -46,6 +64,11 @@
"directory": "DIR",
"command": "clang -c DIR/B.m -isystem modules/A -I modules/B -fmodules -fmodules-cache-path=DIR/module-cache -fimplicit-module-maps -Wmaybe-unused",
"file": "DIR/B.m"
+},
+{
+ "directory": "DIR",
+ "command": "clang -c DIR/C.m -isystem modules/C -fmodules -fmodules-cache-path=DIR/module-cache -fimplicit-module-maps -Wmaybe-unused -Wsystem-headers",
+ "file": "DIR/C.m"
}
]
@@ -69,6 +92,16 @@
typedef int B_t;
+//--- modules/C/module.modulemap
+
+module C [system] {
+ umbrella header "C.h"
+}
+
+//--- modules/C/C.h
+
+typedef int C_t;
+
//--- A.m
#include <A.h>
@@ -82,3 +115,9 @@
#include <B.h>
A_t b = 0;
+
+//--- C.m
+
+#include <C.h>
+
+C_t c = 0;
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