https://github.com/Michael137 created
https://github.com/llvm/llvm-project/pull/102309
This patch changes the way we initialize `BuiltinHeadersInSystemModules` which
is one of the flags controlling Clang's behaviour when the Darwin module is
split into more fine-grained modules. The ClangExpressionParser currently
unconditionally sets `-fbuiltin-headers-in-system-modules` when evaluating
expressions with the `target.import-std-module` setting. This flag should,
however, be set depending on the SDK version (which is what the Clang Darwin
toolchain does).
Unfortunately, the compiler instance that we create with
`ClangExpressionParser` never consults the Clang driver, and thus doesn't
correctly infer `BuiltinHeadersInSystemModules`. Note, this isn't an issue with
the `CompilerInstance` that the `ClangModulesDeclVendor` creates because it
uses the `createInovcation` API, which calls into
`Darwin::addClangTargetOptions`.
This patch mimicks how `sdkSupportsBuiltinModules` is used in
`Darwin::addClangTargetOptions`.
This ensures that the `import-std-module` API tests run cleanly regardless of
SDK version.
The plan is to eventually make the `CompilerInstance` construction in
`ClangExpressionParser` go through the driver, so we can avoid duplicating the
logic in LLDB. But we aren't there yet.
**Implementation**
* We look for the `SDKSettings.json` in the sysroot directory that we found in
DWARF (via `DW_AT_LLVM_sysroot`)
* Then parse this file and extract the SDK version number out of it
* Then mimick `sdkSupportsBuiltinModules` from `Toolchains/Darwin.cpp` and set
`BuiltinHeadersInSystemModules` based on it
rdar://116490281
>From acc93237396ce8de0e9cbbb2716c1017dffec630 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuc...@gmail.com>
Date: Wed, 7 Aug 2024 12:46:24 +0100
Subject: [PATCH] [lldb][ClangExpressionParser] Set
BuiltinHeadersInSystemModules depending on SDK version
---
lldb/include/lldb/Utility/XcodeSDK.h | 14 +++++
.../Clang/ClangExpressionParser.cpp | 52 +++++++++++++++++--
lldb/source/Utility/XcodeSDK.cpp | 21 ++++++++
3 files changed, 84 insertions(+), 3 deletions(-)
diff --git a/lldb/include/lldb/Utility/XcodeSDK.h
b/lldb/include/lldb/Utility/XcodeSDK.h
index 673ea578ffce8..69c7e23d3d0f6 100644
--- a/lldb/include/lldb/Utility/XcodeSDK.h
+++ b/lldb/include/lldb/Utility/XcodeSDK.h
@@ -85,6 +85,20 @@ class XcodeSDK {
/// Whether LLDB feels confident importing Clang modules from this SDK.
static bool SDKSupportsModules(Type type, llvm::VersionTuple version);
static bool SDKSupportsModules(Type desired_type, const FileSpec &sdk_path);
+
+ /// Returns true if the SDK for the specified triple supports
+ /// builtin modules in system headers.
+ ///
+ /// NOTE: should be kept in sync with sdkSupportsBuiltinModules in
+ /// Toolchains/Darwin.cpp
+ ///
+ /// FIXME: this function will be removed once LLDB's ClangExpressionParser
+ /// constructs the compiler instance through the driver/toolchain. See \ref
+ /// SetupImportStdModuleLangOpts
+ ///
+ static bool SDKSupportsBuiltinModules(const llvm::Triple &triple,
+ llvm::VersionTuple sdk_version);
+
/// Return the canonical SDK name, such as "macosx" for the macOS SDK.
static std::string GetCanonicalName(Info info);
/// Return the best-matching SDK type for a specific triple.
diff --git
a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
index f41323d32ac86..3b67d28203c3d 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
@@ -39,6 +39,7 @@
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/Support/CrashRecoveryContext.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/TargetSelect.h"
@@ -91,6 +92,8 @@
#include "lldb/Utility/StringList.h"
#include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h"
+#include "Plugins/Platform/MacOSX/PlatformDarwin.h"
+#include "lldb/Utility/XcodeSDK.h"
#include <cctype>
#include <memory>
@@ -279,6 +282,48 @@ class ClangDiagnosticManagerAdapter : public
clang::DiagnosticConsumer {
std::string m_output;
};
+/// Returns true if the SDK for the specified triple supports
+/// builtin modules in system headers. This is used to decide
+/// whether to pass -fbuiltin-headers-in-system-modules to
+/// the compiler instance when compiling the `std` module.
+///
+/// \param[in] target The target triple.
+///
+static llvm::Expected<bool>
+sdkSupportsBuiltinModules(lldb_private::Target &target) {
+ auto arch_spec = target.GetArchitecture();
+ auto const &triple = arch_spec.GetTriple();
+ auto module_sp = target.GetExecutableModule();
+ if (!module_sp)
+ return llvm::createStringError("Executable module not found.");
+
+ // Get SDK path that the target was compiled against.
+ auto sdk_or_err = PlatformDarwin::GetSDKPathFromDebugInfo(*module_sp);
+ if (!sdk_or_err)
+ return sdk_or_err.takeError();
+
+ // Use the SDK path from debug-info to find a local matching SDK directory.
+ auto sdk_path_or_err =
+ HostInfo::GetSDKRoot(HostInfo::SDKOptions{std::move(sdk_or_err->first)});
+ if (!sdk_path_or_err)
+ return sdk_path_or_err.takeError();
+
+ auto VFS = FileSystem::Instance().GetVirtualFileSystem();
+ if (!VFS)
+ return llvm::createStringError("No virtual filesystem available.");
+
+ // Extract SDK version from the /path/to/some.sdk/SDKSettings.json
+ auto parsed_or_err = clang::parseDarwinSDKInfo(*VFS, *sdk_path_or_err);
+ if (!parsed_or_err)
+ return parsed_or_err.takeError();
+
+ auto maybe_sdk = *parsed_or_err;
+ if (!maybe_sdk)
+ return llvm::createStringError("Couldn't find Darwin SDK info.");
+
+ return XcodeSDK::SDKSupportsBuiltinModules(triple, maybe_sdk->getVersion());
+}
+
static void SetupModuleHeaderPaths(CompilerInstance *compiler,
std::vector<std::string>
include_directories,
lldb::TargetSP target_sp) {
@@ -561,7 +606,8 @@ static void SetupLangOpts(CompilerInstance &compiler,
lang_opts.NoBuiltin = true;
}
-static void SetupImportStdModuleLangOpts(CompilerInstance &compiler) {
+static void SetupImportStdModuleLangOpts(CompilerInstance &compiler,
+ lldb_private::Target &target) {
LangOptions &lang_opts = compiler.getLangOpts();
lang_opts.Modules = true;
// We want to implicitly build modules.
@@ -578,7 +624,7 @@ static void SetupImportStdModuleLangOpts(CompilerInstance
&compiler) {
lang_opts.GNUMode = true;
lang_opts.GNUKeywords = true;
lang_opts.CPlusPlus11 = true;
- lang_opts.BuiltinHeadersInSystemModules = true;
+ lang_opts.BuiltinHeadersInSystemModules = !sdkSupportsBuiltinModules(target);
// The Darwin libc expects this macro to be set.
lang_opts.GNUCVersion = 40201;
@@ -659,7 +705,7 @@ ClangExpressionParser::ClangExpressionParser(
if (auto *clang_expr = dyn_cast<ClangUserExpression>(&m_expr);
clang_expr && clang_expr->DidImportCxxModules()) {
LLDB_LOG(log, "Adding lang options for importing C++ modules");
- SetupImportStdModuleLangOpts(*m_compiler);
+ SetupImportStdModuleLangOpts(*m_compiler, *target_sp);
SetupModuleHeaderPaths(m_compiler.get(), m_include_directories, target_sp);
}
diff --git a/lldb/source/Utility/XcodeSDK.cpp b/lldb/source/Utility/XcodeSDK.cpp
index 712d611db28f8..64e0672a963ca 100644
--- a/lldb/source/Utility/XcodeSDK.cpp
+++ b/lldb/source/Utility/XcodeSDK.cpp
@@ -259,6 +259,27 @@ bool XcodeSDK::SupportsSwift() const {
}
}
+bool XcodeSDK::SDKSupportsBuiltinModules(const llvm::Triple &triple,
+ llvm::VersionTuple sdk_version) {
+ using namespace llvm;
+
+ switch (triple.getOS()) {
+ case Triple::OSType::MacOSX:
+ return sdk_version >= VersionTuple(15U);
+ case Triple::OSType::IOS:
+ return sdk_version >= VersionTuple(18U);
+ case Triple::OSType::TvOS:
+ return sdk_version >= VersionTuple(18U);
+ case Triple::OSType::WatchOS:
+ return sdk_version >= VersionTuple(11U);
+ case Triple::OSType::XROS:
+ return sdk_version >= VersionTuple(2U);
+ default:
+ // New SDKs support builtin modules from the start.
+ return true;
+ }
+}
+
bool XcodeSDK::SDKSupportsModules(XcodeSDK::Type desired_type,
const FileSpec &sdk_path) {
ConstString last_path_component = sdk_path.GetFilename();
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