[clang] [lld] [llvm] [WIP][clang][lld] Dispatch registered linkers through ToolSession (PR #224023)
Anutosh Bhat via cfe-commits
cfe-commits at lists.llvm.org
Wed Sep 16 06:57:49 PDT 2026
https://github.com/anutosh491 created https://github.com/llvm/llvm-project/pull/224023
Please read: [RFC: Embeddable LLVM tool drivers for long-lived hosts](https://discourse.llvm.org/t/rfc-embeddable-llvm-tool-drivers-for-long-lived-hosts/91754)
Depends on #221996 and #222531.
This is the third small patch in the embeddable-tools series. After #222531 allows session-owned Clang to execute multiple `cc1` jobs, this patch allows Clang to dispatch a registered linker through the same `ToolSession`.
Clang continues to construct its normal jobs. A linker job runs in-process only when its executable is registered and belongs to the current session; unrelated external linkers retain the normal subprocess path.
This enables commands such as:
```bash
clang++ --target=wasm32-unknown-emscripten add.cpp main.cpp -o project.wasm
```
to execute as:
```text
ToolSession
└── clang
├── cc1(add.cpp)
├── cc1(main.cpp)
└── wasm-ld(add.o, main.o)
```
The mechanism is target-independent. The tests cover in-process WebAssembly and AArch64/ELF links, ensure an unrelated external `ld` is not intercepted, and exercise repeated LLD execution.
Session-owned LLD uses its existing reusable cleanup path before returning to Clang. Standalone LLD keeps its current fast path.
>From b4491966852910f6fcd22c6c0a1c956211e2e2fc Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Tue, 8 Sep 2026 18:42:12 +0530
Subject: [PATCH 1/6] [Support] Add LLVMToolSession for in-process tool
invocation
---
llvm/include/llvm/Support/LLVMDriver.h | 67 +++++++++-
llvm/lib/Support/CMakeLists.txt | 1 +
llvm/lib/Support/LLVMToolSession.cpp | 119 ++++++++++++++++++
.../tools/llvm-driver/session-dispatch.test | 7 ++
llvm/tools/llvm-driver/llvm-driver.cpp | 66 +++-------
llvm/unittests/Support/CMakeLists.txt | 1 +
.../Support/LLVMToolSession/CMakeLists.txt | 20 +++
.../LLVMToolSession/LLVMToolSessionTest.cpp | 65 ++++++++++
8 files changed, 298 insertions(+), 48 deletions(-)
create mode 100644 llvm/lib/Support/LLVMToolSession.cpp
create mode 100644 llvm/test/tools/llvm-driver/session-dispatch.test
create mode 100644 llvm/unittests/Support/LLVMToolSession/CMakeLists.txt
create mode 100644 llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
diff --git a/llvm/include/llvm/Support/LLVMDriver.h b/llvm/include/llvm/Support/LLVMDriver.h
index 0b2e265d50b42..48122bfaceb7c 100644
--- a/llvm/include/llvm/Support/LLVMDriver.h
+++ b/llvm/include/llvm/Support/LLVMDriver.h
@@ -9,9 +9,35 @@
#ifndef LLVM_SUPPORT_LLVMDRIVER_H
#define LLVM_SUPPORT_LLVMDRIVER_H
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorOr.h"
+
+#include <memory>
+
namespace llvm {
-struct ToolContext {
+class LLVMToolSession;
+class ToolContext;
+
+using ToolMainFn = int (*)(int, char **, const ToolContext &);
+
+/// An LLVM command-line tool that can be invoked without creating a process.
+struct CallableTool {
+ StringRef Name;
+ ToolMainFn Main;
+
+ explicit operator bool() const { return Main != nullptr; }
+};
+
+/// Describes how a tool was invoked and provides access to its host session.
+class ToolContext {
+ LLVMToolSession *Session = nullptr;
+
+ friend class LLVMToolSession;
+
+public:
const char *Path;
const char *PrependArg;
// PrependArg will be added unconditionally by the llvm-driver, but
@@ -20,6 +46,45 @@ struct ToolContext {
// point to the llvm-driver executable, where PrependArg will be needed to
// invoke the correct tool.
bool NeedsPrependArg;
+
+ ToolContext(const char *Path, const char *PrependArg, bool NeedsPrependArg)
+ : Path(Path), PrependArg(PrependArg), NeedsPrependArg(NeedsPrependArg) {}
+
+ /// Finds a tool registered with the session that owns this context.
+ LLVM_ABI ErrorOr<CallableTool> getCallableTool(StringRef Name) const;
+
+ /// Invokes another tool registered with the same host session.
+ LLVM_ABI int callTool(ArrayRef<const char *> Args) const;
+};
+
+/// Owns LLVM process initialization and an in-process tool registry.
+///
+/// A long-lived host constructs one session and uses it for every embedded
+/// tool invocation. The individual tools borrow a ToolContext and therefore do
+/// not initialize or shut down LLVM themselves.
+class LLVM_ABI LLVMToolSession {
+public:
+ LLVMToolSession(int &Argc, char **&Argv, ArrayRef<CallableTool> Tools,
+ bool InstallPipeSignalExitHandler = true,
+ bool NeedsPOSIXUtilitySignalHandling = false);
+ ~LLVMToolSession();
+
+ LLVMToolSession(const LLVMToolSession &) = delete;
+ LLVMToolSession &operator=(const LLVMToolSession &) = delete;
+
+ /// Invokes the tool named by Args[0]. Args may instead contain a
+ /// process-style argv beginning with the session executable or an LLVM
+ /// multicall name.
+ int callTool(ArrayRef<const char *> Args);
+
+private:
+ struct Impl;
+ std::unique_ptr<Impl> PImpl;
+
+ ErrorOr<CallableTool> findTool(StringRef Name) const;
+ ToolContext makeContext(StringRef InvokedName);
+
+ friend class ToolContext;
};
} // namespace llvm
diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
index e7dfcb0dcd891..c5187f856e541 100644
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -229,6 +229,7 @@ add_llvm_component_library(LLVMSupport
LineIterator.cpp
Locale.cpp
LockFileManager.cpp
+ LLVMToolSession.cpp
ManagedStatic.cpp
MathExtras.cpp
MemAlloc.cpp
diff --git a/llvm/lib/Support/LLVMToolSession.cpp b/llvm/lib/Support/LLVMToolSession.cpp
new file mode 100644
index 0000000000000..94f596a9d8903
--- /dev/null
+++ b/llvm/lib/Support/LLVMToolSession.cpp
@@ -0,0 +1,119 @@
+//===-- LLVMToolSession.cpp ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/LLVMDriver.h"
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/Path.h"
+
+#include <string>
+#include <system_error>
+#include <utility>
+#include <vector>
+
+using namespace llvm;
+
+namespace {
+
+bool matchesToolName(StringRef RegisteredName, StringRef InvokedName) {
+ StringRef Stem = sys::path::stem(InvokedName);
+ auto Matches = [RegisteredName](StringRef Candidate) {
+ size_t Position = Candidate.rfind_insensitive(RegisteredName);
+ return Position != StringRef::npos &&
+ (Position + RegisteredName.size() == Candidate.size() ||
+ !llvm::isAlnum(Candidate[Position + RegisteredName.size()]));
+ };
+ return Matches(Stem) || Matches(sys::path::filename(InvokedName));
+}
+
+bool isMulticallName(StringRef Name) { return matchesToolName("llvm", Name); }
+
+} // namespace
+
+struct LLVMToolSession::Impl {
+ InitLLVM Initialization;
+ std::string ExecutablePath;
+ std::vector<std::pair<std::string, ToolMainFn>> Tools;
+
+ Impl(int &Argc, char **&Argv, ArrayRef<CallableTool> RegisteredTools,
+ bool InstallPipeSignalExitHandler, bool NeedsPOSIXUtilitySignalHandling)
+ : Initialization(Argc, Argv, InstallPipeSignalExitHandler,
+ NeedsPOSIXUtilitySignalHandling),
+ ExecutablePath(Argv[0]) {
+ Tools.reserve(RegisteredTools.size());
+ for (const CallableTool &Tool : RegisteredTools)
+ Tools.emplace_back(Tool.Name.str(), Tool.Main);
+ }
+};
+
+LLVMToolSession::LLVMToolSession(int &Argc, char **&Argv,
+ ArrayRef<CallableTool> Tools,
+ bool InstallPipeSignalExitHandler,
+ bool NeedsPOSIXUtilitySignalHandling)
+ : PImpl(std::make_unique<Impl>(Argc, Argv, Tools,
+ InstallPipeSignalExitHandler,
+ NeedsPOSIXUtilitySignalHandling)) {}
+
+LLVMToolSession::~LLVMToolSession() = default;
+
+ErrorOr<CallableTool> LLVMToolSession::findTool(StringRef Name) const {
+ for (const auto &[RegisteredName, Main] : PImpl->Tools)
+ if (matchesToolName(RegisteredName, Name))
+ return CallableTool{RegisteredName, Main};
+ return make_error_code(std::errc::no_such_file_or_directory);
+}
+
+ToolContext LLVMToolSession::makeContext(StringRef InvokedName) {
+ bool NeedsPrependArg = !matchesToolName(InvokedName, PImpl->ExecutablePath);
+ ToolContext Context(PImpl->ExecutablePath.c_str(), InvokedName.data(),
+ NeedsPrependArg);
+ Context.Session = this;
+ return Context;
+}
+
+int LLVMToolSession::callTool(ArrayRef<const char *> Args) {
+ if (Args.empty())
+ return -1;
+
+ StringRef InvokedName = Args.front();
+ ErrorOr<CallableTool> Tool = findTool(InvokedName);
+ if (!Tool) {
+ if (InvokedName != PImpl->ExecutablePath && !isMulticallName(InvokedName))
+ return -1;
+ Args = Args.drop_front();
+ if (Args.empty())
+ return -1;
+ InvokedName = Args.front();
+ Tool = findTool(InvokedName);
+ }
+
+ if (!Tool)
+ return -1;
+
+ ToolContext Context = makeContext(InvokedName);
+ SmallVector<char *, 16> MutableArgs;
+ MutableArgs.reserve(Args.size() + 1);
+ for (const char *Arg : Args)
+ MutableArgs.push_back(const_cast<char *>(Arg));
+ MutableArgs.push_back(nullptr);
+ return Tool->Main(Args.size(), MutableArgs.data(), Context);
+}
+
+ErrorOr<CallableTool> ToolContext::getCallableTool(StringRef Name) const {
+ if (!Session)
+ return make_error_code(std::errc::operation_not_permitted);
+ return Session->findTool(Name);
+}
+
+int ToolContext::callTool(ArrayRef<const char *> Args) const {
+ if (!Session)
+ return -1;
+ return Session->callTool(Args);
+}
diff --git a/llvm/test/tools/llvm-driver/session-dispatch.test b/llvm/test/tools/llvm-driver/session-dispatch.test
new file mode 100644
index 0000000000000..6ac93be6ce431
--- /dev/null
+++ b/llvm/test/tools/llvm-driver/session-dispatch.test
@@ -0,0 +1,7 @@
+# REQUIRES: llvm-driver
+
+## Exercise a real LLVM tool entry point through LLVMToolSession rather than
+## only testing the registry with synthetic callbacks.
+# RUN: %llvm cxxfilt _Z3foov | FileCheck %s
+
+# CHECK: foo()
diff --git a/llvm/tools/llvm-driver/llvm-driver.cpp b/llvm/tools/llvm-driver/llvm-driver.cpp
index 14ce162faee46..865d6d432d473 100644
--- a/llvm/tools/llvm-driver/llvm-driver.cpp
+++ b/llvm/tools/llvm-driver/llvm-driver.cpp
@@ -6,14 +6,11 @@
//
//===----------------------------------------------------------------------===//
-#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/InitLLVM.h"
#include "llvm/Support/LLVMDriver.h"
#include "llvm/Support/Path.h"
-#include "llvm/Support/WithColor.h"
+#include "llvm/Support/raw_ostream.h"
using namespace llvm;
@@ -36,51 +33,26 @@ static void printHelpMessage() {
<< "OPTIONS:\n\n --help - Display this message\n";
}
-static int findTool(int Argc, char **Argv, const char *Argv0) {
- if (!Argc) {
- printHelpMessage();
- return 1;
- }
+int main(int Argc, char **Argv) {
+ const CallableTool Tools[] = {
+#define LLVM_DRIVER_TOOL(tool, entry) {tool, entry##_main},
+#include "LLVMDriverTools.def"
+ };
- StringRef ToolName = Argv[0];
+ LLVMToolSession Session(Argc, Argv, Tools);
- if (ToolName == "--help") {
+ StringRef Stem = sys::path::stem(Argv[0]);
+ if (Stem.equals_insensitive("llvm") &&
+ (Argc == 1 || (Argc == 2 && StringRef(Argv[1]) == "--help"))) {
printHelpMessage();
- return 0;
+ return Argc == 1 ? 1 : 0;
}
- StringRef Stem = sys::path::stem(ToolName);
- auto Is = [=](StringRef Tool) {
- auto IsImpl = [=](StringRef Stem) {
- auto I = Stem.rfind_insensitive(Tool);
- return I != StringRef::npos && (I + Tool.size() == Stem.size() ||
- !llvm::isAlnum(Stem[I + Tool.size()]));
- };
- for (StringRef S : {Stem, sys::path::filename(ToolName)})
- if (IsImpl(S))
- return true;
- return false;
- };
-
- auto MakeDriverArgs = [=]() -> llvm::ToolContext {
- if (ToolName != Argv0)
- return {Argv0, ToolName.data(), true};
- return {Argv0, sys::path::filename(Argv0).data(), false};
- };
-
-#define LLVM_DRIVER_TOOL(tool, entry) \
- if (Is(tool)) \
- return entry##_main(Argc, Argv, MakeDriverArgs());
-#include "LLVMDriverTools.def"
-
- if (Is("llvm") || Argv0 == Argv[0])
- return findTool(Argc - 1, Argv + 1, Argv0);
-
- printHelpMessage();
- return 1;
-}
-
-int main(int Argc, char **Argv) {
- llvm::InitLLVM X(Argc, Argv);
- return findTool(Argc, Argv, Argv[0]);
+ SmallVector<const char *, 16> Args(Argv, Argv + Argc);
+ int Result = Session.callTool(Args);
+ if (Result == -1) {
+ printHelpMessage();
+ return 1;
+ }
+ return Result;
}
diff --git a/llvm/unittests/Support/CMakeLists.txt b/llvm/unittests/Support/CMakeLists.txt
index cc88a6c5670ca..f9732ff4e0e4b 100644
--- a/llvm/unittests/Support/CMakeLists.txt
+++ b/llvm/unittests/Support/CMakeLists.txt
@@ -162,3 +162,4 @@ if(NOT LLVM_INTEGRATED_CRT_ALLOC)
endif()
add_subdirectory(CommandLineInit)
+add_subdirectory(LLVMToolSession)
diff --git a/llvm/unittests/Support/LLVMToolSession/CMakeLists.txt b/llvm/unittests/Support/LLVMToolSession/CMakeLists.txt
new file mode 100644
index 0000000000000..2d343295fb191
--- /dev/null
+++ b/llvm/unittests/Support/LLVMToolSession/CMakeLists.txt
@@ -0,0 +1,20 @@
+set(test_name LLVMToolSessionTests)
+set(test_suite UnitTests)
+
+# This test supplies its own main() so a single LLVMToolSession can own
+# InitLLVM for the complete test process.
+if (NOT LLVM_BUILD_TESTS)
+ set(EXCLUDE_FROM_ALL ON)
+endif()
+
+list(APPEND LLVM_LINK_COMPONENTS Support)
+
+add_llvm_executable(${test_name}
+ IGNORE_EXTERNALIZE_DEBUGINFO NO_INSTALL_RPATH
+ LLVMToolSessionTest.cpp)
+
+target_link_libraries(${test_name} PRIVATE llvm_gtest)
+add_dependencies(${test_suite} ${test_name})
+
+set(outdir ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR})
+set_output_directory(${test_name} BINARY_DIR ${outdir} LIBRARY_DIR ${outdir})
diff --git a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
new file mode 100644
index 0000000000000..a8a12f3a7e4d1
--- /dev/null
+++ b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
@@ -0,0 +1,65 @@
+//===- LLVMToolSessionTest.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/LLVMDriver.h"
+#include "gtest/gtest.h"
+
+#include <memory>
+
+using namespace llvm;
+
+namespace {
+
+std::unique_ptr<LLVMToolSession> Session;
+unsigned CompilerCalls;
+unsigned LinkerCalls;
+
+int linkerMain(int Argc, char **Argv, const ToolContext &Context) {
+ ++LinkerCalls;
+ EXPECT_EQ(Argc, 3);
+ EXPECT_STREQ(Argv[0], "wasm-ld");
+ EXPECT_TRUE(Context.getCallableTool("clang"));
+ return 0;
+}
+
+int compilerMain(int Argc, char **Argv, const ToolContext &Context) {
+ ++CompilerCalls;
+ EXPECT_EQ(Argc, 2);
+ EXPECT_STREQ(Argv[0], "clang");
+ const char *LinkArgs[] = {"wasm-ld", Argv[1], "out.wasm"};
+ return Context.callTool(LinkArgs);
+}
+
+TEST(LLVMToolSessionTest, SupportsSequentialNestedToolCalls) {
+ const char *First[] = {"clang", "first.cpp"};
+ const char *Second[] = {"clang", "second.cpp"};
+
+ EXPECT_EQ(Session->callTool(First), 0);
+ EXPECT_EQ(Session->callTool(Second), 0);
+ EXPECT_EQ(CompilerCalls, 2u);
+ EXPECT_EQ(LinkerCalls, 2u);
+}
+
+TEST(LLVMToolSessionTest, ReportsUnknownTools) {
+ const char *Args[] = {"not-an-llvm-tool"};
+ EXPECT_EQ(Session->callTool(Args), -1);
+}
+
+} // namespace
+
+int main(int Argc, char **Argv) {
+ const CallableTool Tools[] = {
+ {"clang", compilerMain},
+ {"wasm-ld", linkerMain},
+ };
+ Session = std::make_unique<LLVMToolSession>(Argc, Argv, Tools);
+ testing::InitGoogleTest(&Argc, Argv);
+ int Result = RUN_ALL_TESTS();
+ Session.reset();
+ return Result;
+}
>From 70d8573986c1c4596f4dca3f62afa7497670e94f Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Fri, 11 Sep 2026 10:54:05 +0530
Subject: [PATCH 2/6] [Support] Address LLVMToolSession review feedback
---
llvm/include/llvm/Support/LLVMDriver.h | 14 ++--
llvm/lib/Support/CMakeLists.txt | 2 +-
llvm/lib/Support/LLVMToolSession.cpp | 41 ++++++----
.../tools/llvm-driver/session-dispatch.test | 6 +-
llvm/tools/llvm-driver/llvm-driver.cpp | 6 +-
.../LLVMToolSession/LLVMToolSessionTest.cpp | 76 +++++++++++++++++--
6 files changed, 113 insertions(+), 32 deletions(-)
diff --git a/llvm/include/llvm/Support/LLVMDriver.h b/llvm/include/llvm/Support/LLVMDriver.h
index 48122bfaceb7c..e1107b0ba57f0 100644
--- a/llvm/include/llvm/Support/LLVMDriver.h
+++ b/llvm/include/llvm/Support/LLVMDriver.h
@@ -14,6 +14,7 @@
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorOr.h"
+#include <functional>
#include <memory>
namespace llvm {
@@ -21,14 +22,14 @@ namespace llvm {
class LLVMToolSession;
class ToolContext;
-using ToolMainFn = int (*)(int, char **, const ToolContext &);
+using ToolMainFn = std::function<int(int, char **, const ToolContext &)>;
/// An LLVM command-line tool that can be invoked without creating a process.
struct CallableTool {
StringRef Name;
ToolMainFn Main;
- explicit operator bool() const { return Main != nullptr; }
+ explicit operator bool() const { return static_cast<bool>(Main); }
};
/// Describes how a tool was invoked and provides access to its host session.
@@ -54,7 +55,7 @@ class ToolContext {
LLVM_ABI ErrorOr<CallableTool> getCallableTool(StringRef Name) const;
/// Invokes another tool registered with the same host session.
- LLVM_ABI int callTool(ArrayRef<const char *> Args) const;
+ LLVM_ABI ErrorOr<int> callTool(ArrayRef<const char *> Args) const;
};
/// Owns LLVM process initialization and an in-process tool registry.
@@ -62,6 +63,9 @@ class ToolContext {
/// A long-lived host constructs one session and uses it for every embedded
/// tool invocation. The individual tools borrow a ToolContext and therefore do
/// not initialize or shut down LLVM themselves.
+///
+/// LLVM tools may use process-global state. Tool invocations must be externally
+/// serialized; concurrent calls are not supported.
class LLVM_ABI LLVMToolSession {
public:
LLVMToolSession(int &Argc, char **&Argv, ArrayRef<CallableTool> Tools,
@@ -75,14 +79,14 @@ class LLVM_ABI LLVMToolSession {
/// Invokes the tool named by Args[0]. Args may instead contain a
/// process-style argv beginning with the session executable or an LLVM
/// multicall name.
- int callTool(ArrayRef<const char *> Args);
+ ErrorOr<int> callTool(ArrayRef<const char *> Args);
private:
struct Impl;
std::unique_ptr<Impl> PImpl;
ErrorOr<CallableTool> findTool(StringRef Name) const;
- ToolContext makeContext(StringRef InvokedName);
+ ToolContext makeContext(StringRef InvokedName, const char *PrependArg);
friend class ToolContext;
};
diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
index c5187f856e541..2b2e6516e54f2 100644
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -227,9 +227,9 @@ add_llvm_component_library(LLVMSupport
KnownFPClass.cpp
LEB128.cpp
LineIterator.cpp
+ LLVMToolSession.cpp
Locale.cpp
LockFileManager.cpp
- LLVMToolSession.cpp
ManagedStatic.cpp
MathExtras.cpp
MemAlloc.cpp
diff --git a/llvm/lib/Support/LLVMToolSession.cpp b/llvm/lib/Support/LLVMToolSession.cpp
index 94f596a9d8903..ff63f31ce965c 100644
--- a/llvm/lib/Support/LLVMToolSession.cpp
+++ b/llvm/lib/Support/LLVMToolSession.cpp
@@ -13,6 +13,7 @@
#include "llvm/Support/InitLLVM.h"
#include "llvm/Support/Path.h"
+#include <cassert>
#include <string>
#include <system_error>
#include <utility>
@@ -56,48 +57,60 @@ struct LLVMToolSession::Impl {
LLVMToolSession::LLVMToolSession(int &Argc, char **&Argv,
ArrayRef<CallableTool> Tools,
bool InstallPipeSignalExitHandler,
- bool NeedsPOSIXUtilitySignalHandling)
- : PImpl(std::make_unique<Impl>(Argc, Argv, Tools,
- InstallPipeSignalExitHandler,
- NeedsPOSIXUtilitySignalHandling)) {}
+ bool NeedsPOSIXUtilitySignalHandling) {
+ assert(Argc > 0 && Argv && Argv[0] &&
+ "LLVMToolSession requires a valid argv[0]");
+ PImpl = std::make_unique<Impl>(Argc, Argv, Tools,
+ InstallPipeSignalExitHandler,
+ NeedsPOSIXUtilitySignalHandling);
+}
LLVMToolSession::~LLVMToolSession() = default;
ErrorOr<CallableTool> LLVMToolSession::findTool(StringRef Name) const {
+ StringRef Stem = sys::path::stem(Name);
+ StringRef Filename = sys::path::filename(Name);
+ for (const auto &[RegisteredName, Main] : PImpl->Tools)
+ if (Stem.equals_insensitive(RegisteredName) ||
+ Filename.equals_insensitive(RegisteredName))
+ return CallableTool{RegisteredName, Main};
+
for (const auto &[RegisteredName, Main] : PImpl->Tools)
if (matchesToolName(RegisteredName, Name))
return CallableTool{RegisteredName, Main};
return make_error_code(std::errc::no_such_file_or_directory);
}
-ToolContext LLVMToolSession::makeContext(StringRef InvokedName) {
+ToolContext LLVMToolSession::makeContext(StringRef InvokedName,
+ const char *PrependArg) {
bool NeedsPrependArg = !matchesToolName(InvokedName, PImpl->ExecutablePath);
- ToolContext Context(PImpl->ExecutablePath.c_str(), InvokedName.data(),
+ ToolContext Context(PImpl->ExecutablePath.c_str(), PrependArg,
NeedsPrependArg);
Context.Session = this;
return Context;
}
-int LLVMToolSession::callTool(ArrayRef<const char *> Args) {
+ErrorOr<int> LLVMToolSession::callTool(ArrayRef<const char *> Args) {
if (Args.empty())
- return -1;
+ return make_error_code(std::errc::invalid_argument);
StringRef InvokedName = Args.front();
ErrorOr<CallableTool> Tool = findTool(InvokedName);
if (!Tool) {
if (InvokedName != PImpl->ExecutablePath && !isMulticallName(InvokedName))
- return -1;
+ return make_error_code(std::errc::no_such_file_or_directory);
Args = Args.drop_front();
if (Args.empty())
- return -1;
+ return make_error_code(std::errc::invalid_argument);
InvokedName = Args.front();
Tool = findTool(InvokedName);
}
if (!Tool)
- return -1;
+ return Tool.getError();
- ToolContext Context = makeContext(InvokedName);
+ std::string PrependArg = sys::path::stem(InvokedName).str();
+ ToolContext Context = makeContext(InvokedName, PrependArg.c_str());
SmallVector<char *, 16> MutableArgs;
MutableArgs.reserve(Args.size() + 1);
for (const char *Arg : Args)
@@ -112,8 +125,8 @@ ErrorOr<CallableTool> ToolContext::getCallableTool(StringRef Name) const {
return Session->findTool(Name);
}
-int ToolContext::callTool(ArrayRef<const char *> Args) const {
+ErrorOr<int> ToolContext::callTool(ArrayRef<const char *> Args) const {
if (!Session)
- return -1;
+ return make_error_code(std::errc::operation_not_permitted);
return Session->callTool(Args);
}
diff --git a/llvm/test/tools/llvm-driver/session-dispatch.test b/llvm/test/tools/llvm-driver/session-dispatch.test
index 6ac93be6ce431..609d40cb505e9 100644
--- a/llvm/test/tools/llvm-driver/session-dispatch.test
+++ b/llvm/test/tools/llvm-driver/session-dispatch.test
@@ -2,6 +2,8 @@
## Exercise a real LLVM tool entry point through LLVMToolSession rather than
## only testing the registry with synthetic callbacks.
-# RUN: %llvm cxxfilt _Z3foov | FileCheck %s
+# RUN: %llvm cxxfilt _Z3foov | FileCheck %s --check-prefix=CXXFILT
+# RUN: %llvm --help | FileCheck %s --check-prefix=HELP
-# CHECK: foo()
+# CXXFILT: foo()
+# HELP: OVERVIEW: llvm toolchain driver
diff --git a/llvm/tools/llvm-driver/llvm-driver.cpp b/llvm/tools/llvm-driver/llvm-driver.cpp
index 865d6d432d473..b9fd476beb8c2 100644
--- a/llvm/tools/llvm-driver/llvm-driver.cpp
+++ b/llvm/tools/llvm-driver/llvm-driver.cpp
@@ -49,10 +49,10 @@ int main(int Argc, char **Argv) {
}
SmallVector<const char *, 16> Args(Argv, Argv + Argc);
- int Result = Session.callTool(Args);
- if (Result == -1) {
+ ErrorOr<int> Result = Session.callTool(Args);
+ if (!Result) {
printHelpMessage();
return 1;
}
- return Result;
+ return *Result;
}
diff --git a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
index a8a12f3a7e4d1..7d604396716d0 100644
--- a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
+++ b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
@@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/Support/LLVMDriver.h"
+#include "llvm/Support/CommandLine.h"
#include "gtest/gtest.h"
#include <memory>
@@ -18,6 +19,7 @@ namespace {
std::unique_ptr<LLVMToolSession> Session;
unsigned CompilerCalls;
unsigned LinkerCalls;
+unsigned WrapperCalls;
int linkerMain(int Argc, char **Argv, const ToolContext &Context) {
++LinkerCalls;
@@ -32,29 +34,89 @@ int compilerMain(int Argc, char **Argv, const ToolContext &Context) {
EXPECT_EQ(Argc, 2);
EXPECT_STREQ(Argv[0], "clang");
const char *LinkArgs[] = {"wasm-ld", Argv[1], "out.wasm"};
- return Context.callTool(LinkArgs);
+ ErrorOr<int> Result = Context.callTool(LinkArgs);
+ EXPECT_TRUE(Result);
+ return Result ? *Result : 1;
+}
+
+int clangWrapperMain(int Argc, char **Argv, const ToolContext &Context) {
+ ++WrapperCalls;
+ EXPECT_EQ(Argc, 1);
+ EXPECT_STREQ(Argv[0], "/tmp/clang-wrapper.exe");
+ EXPECT_STREQ(Context.PrependArg, "clang-wrapper");
+ return 0;
+}
+
+int resetOptionsMain(int, char **, const ToolContext &) {
+ cl::ResetAllOptionOccurrences();
+ return 0;
}
TEST(LLVMToolSessionTest, SupportsSequentialNestedToolCalls) {
+ unsigned CompilerCallsBefore = CompilerCalls;
+ unsigned LinkerCallsBefore = LinkerCalls;
const char *First[] = {"clang", "first.cpp"};
const char *Second[] = {"clang", "second.cpp"};
- EXPECT_EQ(Session->callTool(First), 0);
- EXPECT_EQ(Session->callTool(Second), 0);
- EXPECT_EQ(CompilerCalls, 2u);
- EXPECT_EQ(LinkerCalls, 2u);
+ ErrorOr<int> FirstResult = Session->callTool(First);
+ ASSERT_TRUE(FirstResult);
+ EXPECT_EQ(*FirstResult, 0);
+ ErrorOr<int> SecondResult = Session->callTool(Second);
+ ASSERT_TRUE(SecondResult);
+ EXPECT_EQ(*SecondResult, 0);
+ EXPECT_EQ(CompilerCalls, CompilerCallsBefore + 2);
+ EXPECT_EQ(LinkerCalls, LinkerCallsBefore + 2);
}
TEST(LLVMToolSessionTest, ReportsUnknownTools) {
- const char *Args[] = {"not-an-llvm-tool"};
- EXPECT_EQ(Session->callTool(Args), -1);
+ const char *Args[] = {"not-a-tool"};
+ ErrorOr<int> Result = Session->callTool(Args);
+ EXPECT_FALSE(Result);
+ EXPECT_EQ(Result.getError(),
+ make_error_code(std::errc::no_such_file_or_directory));
+}
+
+TEST(LLVMToolSessionTest, SupportsStatefulCallableTools) {
+ const char *Args[] = {"stateful-tool"};
+ ErrorOr<int> Result = Session->callTool(Args);
+ ASSERT_TRUE(Result);
+ EXPECT_EQ(*Result, 42);
+}
+
+TEST(LLVMToolSessionTest, PrefersExactToolNameBeforeFuzzyMatch) {
+ const char *Args[] = {"/tmp/clang-wrapper.exe"};
+ ErrorOr<int> Result = Session->callTool(Args);
+ ASSERT_TRUE(Result);
+ EXPECT_EQ(*Result, 0);
+ EXPECT_EQ(WrapperCalls, 1u);
+}
+
+TEST(LLVMToolSessionTest, SurvivesCommandLineOptionReset) {
+ const char *ResetArgs[] = {"reset-options"};
+ ErrorOr<int> ResetResult = Session->callTool(ResetArgs);
+ ASSERT_TRUE(ResetResult);
+ EXPECT_EQ(*ResetResult, 0);
+
+ unsigned CompilerCallsBefore = CompilerCalls;
+ const char *CompilerArgs[] = {"clang", "after-reset.cpp"};
+ ErrorOr<int> CompilerResult = Session->callTool(CompilerArgs);
+ ASSERT_TRUE(CompilerResult);
+ EXPECT_EQ(*CompilerResult, 0);
+ EXPECT_EQ(CompilerCalls, CompilerCallsBefore + 1);
}
} // namespace
int main(int Argc, char **Argv) {
+ int StatefulResult = 42;
const CallableTool Tools[] = {
{"clang", compilerMain},
+ {"clang-wrapper", clangWrapperMain},
+ {"reset-options", resetOptionsMain},
+ {"stateful-tool",
+ [&StatefulResult](int, char **, const ToolContext &) {
+ return StatefulResult;
+ }},
{"wasm-ld", linkerMain},
};
Session = std::make_unique<LLVMToolSession>(Argc, Argv, Tools);
>From c40d89063f1f141cf5e1f7be1e7f9e5bfe1306e3 Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Fri, 11 Sep 2026 11:01:24 +0530
Subject: [PATCH 3/6] [Support] Apply clang-format
---
llvm/lib/Support/LLVMToolSession.cpp | 6 +++---
.../Support/LLVMToolSession/LLVMToolSessionTest.cpp | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/Support/LLVMToolSession.cpp b/llvm/lib/Support/LLVMToolSession.cpp
index ff63f31ce965c..c92ef835fab7a 100644
--- a/llvm/lib/Support/LLVMToolSession.cpp
+++ b/llvm/lib/Support/LLVMToolSession.cpp
@@ -60,9 +60,9 @@ LLVMToolSession::LLVMToolSession(int &Argc, char **&Argv,
bool NeedsPOSIXUtilitySignalHandling) {
assert(Argc > 0 && Argv && Argv[0] &&
"LLVMToolSession requires a valid argv[0]");
- PImpl = std::make_unique<Impl>(Argc, Argv, Tools,
- InstallPipeSignalExitHandler,
- NeedsPOSIXUtilitySignalHandling);
+ PImpl =
+ std::make_unique<Impl>(Argc, Argv, Tools, InstallPipeSignalExitHandler,
+ NeedsPOSIXUtilitySignalHandling);
}
LLVMToolSession::~LLVMToolSession() = default;
diff --git a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
index 7d604396716d0..a358279c2820d 100644
--- a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
+++ b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
@@ -6,8 +6,8 @@
//
//===----------------------------------------------------------------------===//
-#include "llvm/Support/LLVMDriver.h"
#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/LLVMDriver.h"
#include "gtest/gtest.h"
#include <memory>
>From 79e0c343fd4ce0d4c31a816819955e08daab315e Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Wed, 16 Sep 2026 15:37:32 +0530
Subject: [PATCH 4/6] [Support] Rename LLVMToolSession to ToolSession
---
llvm/include/llvm/Support/LLVMDriver.h | 20 +++++++--------
llvm/lib/Support/LLVMToolSession.cpp | 25 +++++++++----------
.../tools/llvm-driver/session-dispatch.test | 2 +-
llvm/tools/llvm-driver/llvm-driver.cpp | 2 +-
.../Support/LLVMToolSession/CMakeLists.txt | 2 +-
.../LLVMToolSession/LLVMToolSessionTest.cpp | 4 +--
6 files changed, 27 insertions(+), 28 deletions(-)
diff --git a/llvm/include/llvm/Support/LLVMDriver.h b/llvm/include/llvm/Support/LLVMDriver.h
index e1107b0ba57f0..83025c9c8e34a 100644
--- a/llvm/include/llvm/Support/LLVMDriver.h
+++ b/llvm/include/llvm/Support/LLVMDriver.h
@@ -19,7 +19,7 @@
namespace llvm {
-class LLVMToolSession;
+class ToolSession;
class ToolContext;
using ToolMainFn = std::function<int(int, char **, const ToolContext &)>;
@@ -34,9 +34,9 @@ struct CallableTool {
/// Describes how a tool was invoked and provides access to its host session.
class ToolContext {
- LLVMToolSession *Session = nullptr;
+ ToolSession *Session = nullptr;
- friend class LLVMToolSession;
+ friend class ToolSession;
public:
const char *Path;
@@ -66,15 +66,15 @@ class ToolContext {
///
/// LLVM tools may use process-global state. Tool invocations must be externally
/// serialized; concurrent calls are not supported.
-class LLVM_ABI LLVMToolSession {
+class LLVM_ABI ToolSession {
public:
- LLVMToolSession(int &Argc, char **&Argv, ArrayRef<CallableTool> Tools,
- bool InstallPipeSignalExitHandler = true,
- bool NeedsPOSIXUtilitySignalHandling = false);
- ~LLVMToolSession();
+ ToolSession(int &Argc, char **&Argv, ArrayRef<CallableTool> Tools,
+ bool InstallPipeSignalExitHandler = true,
+ bool NeedsPOSIXUtilitySignalHandling = false);
+ ~ToolSession();
- LLVMToolSession(const LLVMToolSession &) = delete;
- LLVMToolSession &operator=(const LLVMToolSession &) = delete;
+ ToolSession(const ToolSession &) = delete;
+ ToolSession &operator=(const ToolSession &) = delete;
/// Invokes the tool named by Args[0]. Args may instead contain a
/// process-style argv beginning with the session executable or an LLVM
diff --git a/llvm/lib/Support/LLVMToolSession.cpp b/llvm/lib/Support/LLVMToolSession.cpp
index c92ef835fab7a..93704610af38c 100644
--- a/llvm/lib/Support/LLVMToolSession.cpp
+++ b/llvm/lib/Support/LLVMToolSession.cpp
@@ -25,20 +25,21 @@ namespace {
bool matchesToolName(StringRef RegisteredName, StringRef InvokedName) {
StringRef Stem = sys::path::stem(InvokedName);
+ StringRef Filename = sys::path::filename(InvokedName);
auto Matches = [RegisteredName](StringRef Candidate) {
size_t Position = Candidate.rfind_insensitive(RegisteredName);
return Position != StringRef::npos &&
(Position + RegisteredName.size() == Candidate.size() ||
!llvm::isAlnum(Candidate[Position + RegisteredName.size()]));
};
- return Matches(Stem) || Matches(sys::path::filename(InvokedName));
+ return Matches(Stem) || Matches(Filename);
}
bool isMulticallName(StringRef Name) { return matchesToolName("llvm", Name); }
} // namespace
-struct LLVMToolSession::Impl {
+struct ToolSession::Impl {
InitLLVM Initialization;
std::string ExecutablePath;
std::vector<std::pair<std::string, ToolMainFn>> Tools;
@@ -54,20 +55,18 @@ struct LLVMToolSession::Impl {
}
};
-LLVMToolSession::LLVMToolSession(int &Argc, char **&Argv,
- ArrayRef<CallableTool> Tools,
- bool InstallPipeSignalExitHandler,
- bool NeedsPOSIXUtilitySignalHandling) {
- assert(Argc > 0 && Argv && Argv[0] &&
- "LLVMToolSession requires a valid argv[0]");
+ToolSession::ToolSession(int &Argc, char **&Argv, ArrayRef<CallableTool> Tools,
+ bool InstallPipeSignalExitHandler,
+ bool NeedsPOSIXUtilitySignalHandling) {
+ assert(Argc > 0 && Argv && Argv[0] && "ToolSession requires a valid argv[0]");
PImpl =
std::make_unique<Impl>(Argc, Argv, Tools, InstallPipeSignalExitHandler,
NeedsPOSIXUtilitySignalHandling);
}
-LLVMToolSession::~LLVMToolSession() = default;
+ToolSession::~ToolSession() = default;
-ErrorOr<CallableTool> LLVMToolSession::findTool(StringRef Name) const {
+ErrorOr<CallableTool> ToolSession::findTool(StringRef Name) const {
StringRef Stem = sys::path::stem(Name);
StringRef Filename = sys::path::filename(Name);
for (const auto &[RegisteredName, Main] : PImpl->Tools)
@@ -81,8 +80,8 @@ ErrorOr<CallableTool> LLVMToolSession::findTool(StringRef Name) const {
return make_error_code(std::errc::no_such_file_or_directory);
}
-ToolContext LLVMToolSession::makeContext(StringRef InvokedName,
- const char *PrependArg) {
+ToolContext ToolSession::makeContext(StringRef InvokedName,
+ const char *PrependArg) {
bool NeedsPrependArg = !matchesToolName(InvokedName, PImpl->ExecutablePath);
ToolContext Context(PImpl->ExecutablePath.c_str(), PrependArg,
NeedsPrependArg);
@@ -90,7 +89,7 @@ ToolContext LLVMToolSession::makeContext(StringRef InvokedName,
return Context;
}
-ErrorOr<int> LLVMToolSession::callTool(ArrayRef<const char *> Args) {
+ErrorOr<int> ToolSession::callTool(ArrayRef<const char *> Args) {
if (Args.empty())
return make_error_code(std::errc::invalid_argument);
diff --git a/llvm/test/tools/llvm-driver/session-dispatch.test b/llvm/test/tools/llvm-driver/session-dispatch.test
index 609d40cb505e9..a8e627f5a1305 100644
--- a/llvm/test/tools/llvm-driver/session-dispatch.test
+++ b/llvm/test/tools/llvm-driver/session-dispatch.test
@@ -1,6 +1,6 @@
# REQUIRES: llvm-driver
-## Exercise a real LLVM tool entry point through LLVMToolSession rather than
+## Exercise a real LLVM tool entry point through ToolSession rather than
## only testing the registry with synthetic callbacks.
# RUN: %llvm cxxfilt _Z3foov | FileCheck %s --check-prefix=CXXFILT
# RUN: %llvm --help | FileCheck %s --check-prefix=HELP
diff --git a/llvm/tools/llvm-driver/llvm-driver.cpp b/llvm/tools/llvm-driver/llvm-driver.cpp
index b9fd476beb8c2..bfc0f5355ca07 100644
--- a/llvm/tools/llvm-driver/llvm-driver.cpp
+++ b/llvm/tools/llvm-driver/llvm-driver.cpp
@@ -39,7 +39,7 @@ int main(int Argc, char **Argv) {
#include "LLVMDriverTools.def"
};
- LLVMToolSession Session(Argc, Argv, Tools);
+ ToolSession Session(Argc, Argv, Tools);
StringRef Stem = sys::path::stem(Argv[0]);
if (Stem.equals_insensitive("llvm") &&
diff --git a/llvm/unittests/Support/LLVMToolSession/CMakeLists.txt b/llvm/unittests/Support/LLVMToolSession/CMakeLists.txt
index 2d343295fb191..2c61f3c535615 100644
--- a/llvm/unittests/Support/LLVMToolSession/CMakeLists.txt
+++ b/llvm/unittests/Support/LLVMToolSession/CMakeLists.txt
@@ -1,7 +1,7 @@
set(test_name LLVMToolSessionTests)
set(test_suite UnitTests)
-# This test supplies its own main() so a single LLVMToolSession can own
+# This test supplies its own main() so a single ToolSession can own
# InitLLVM for the complete test process.
if (NOT LLVM_BUILD_TESTS)
set(EXCLUDE_FROM_ALL ON)
diff --git a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
index a358279c2820d..6d3116fbcf55f 100644
--- a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
+++ b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
@@ -16,7 +16,7 @@ using namespace llvm;
namespace {
-std::unique_ptr<LLVMToolSession> Session;
+std::unique_ptr<ToolSession> Session;
unsigned CompilerCalls;
unsigned LinkerCalls;
unsigned WrapperCalls;
@@ -119,7 +119,7 @@ int main(int Argc, char **Argv) {
}},
{"wasm-ld", linkerMain},
};
- Session = std::make_unique<LLVMToolSession>(Argc, Argv, Tools);
+ Session = std::make_unique<ToolSession>(Argc, Argv, Tools);
testing::InitGoogleTest(&Argc, Argv);
int Result = RUN_ALL_TESTS();
Session.reset();
>From d20ad0bb66d666b787db9d626e826b861c40a862 Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Thu, 10 Sep 2026 12:22:00 +0530
Subject: [PATCH 5/6] [clang] Support multiple in-process cc1 jobs in a
ToolSession
---
clang/include/clang/Driver/Job.h | 6 ++++
clang/lib/Driver/Job.cpp | 8 +++++
clang/test/Driver/cc1-spawnprocess.c | 2 ++
clang/test/Driver/clang-translation.c | 2 --
clang/test/Driver/in-process-multiple-cc1.c | 36 +++++++++++++++++++
clang/tools/driver/driver.cpp | 13 +++++++
llvm/include/llvm/Support/LLVMDriver.h | 3 ++
.../LLVMToolSession/LLVMToolSessionTest.cpp | 6 ++++
8 files changed, 74 insertions(+), 2 deletions(-)
create mode 100644 clang/test/Driver/in-process-multiple-cc1.c
diff --git a/clang/include/clang/Driver/Job.h b/clang/include/clang/Driver/Job.h
index 03779be5b5a6a..796acafc1fae9 100644
--- a/clang/include/clang/Driver/Job.h
+++ b/clang/include/clang/Driver/Job.h
@@ -177,6 +177,9 @@ class Command {
/// Whether the command will be executed in this process or not.
bool InProcess = false;
+ /// Whether this command accepts -disable-free.
+ bool SupportsDisableFree = false;
+
Command(const Action &Source, const Tool &Creator,
ResponseFileSupport ResponseSupport, const char *Executable,
const llvm::opt::ArgStringList &Arguments, ArrayRef<InputInfo> Inputs,
@@ -238,6 +241,9 @@ class Command {
void replaceExecutable(const char *Exe) { Executable = Exe; }
+ /// Ensure that this command frees memory before returning to its caller.
+ void enableFree();
+
const char *getExecutable() const { return Executable; }
const llvm::opt::ArgStringList &getArguments() const { return Arguments; }
diff --git a/clang/lib/Driver/Job.cpp b/clang/lib/Driver/Job.cpp
index da7a1f2e07e90..6eddb3f53c3e7 100644
--- a/clang/lib/Driver/Job.cpp
+++ b/clang/lib/Driver/Job.cpp
@@ -13,6 +13,7 @@
#include "clang/Driver/Tool.h"
#include "clang/Driver/ToolChain.h"
#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
@@ -387,6 +388,12 @@ int Command::Execute(ArrayRef<std::optional<StringRef>> Redirects,
ErrMsg, ExecutionFailed, &ProcStat);
}
+void Command::enableFree() {
+ llvm::erase_if(Arguments, [](const char *Arg) {
+ return StringRef(Arg) == "-disable-free";
+ });
+}
+
CC1Command::CC1Command(const Action &Source, const Tool &Creator,
ResponseFileSupport ResponseSupport,
const char *Executable,
@@ -396,6 +403,7 @@ CC1Command::CC1Command(const Action &Source, const Tool &Creator,
: Command(Source, Creator, ResponseSupport, Executable, Arguments, Inputs,
Outputs, PrependArg) {
InProcess = true;
+ SupportsDisableFree = true;
}
void CC1Command::Print(raw_ostream &OS, const char *Terminator, bool Quote,
diff --git a/clang/test/Driver/cc1-spawnprocess.c b/clang/test/Driver/cc1-spawnprocess.c
index a6ff7d148604e..deb774e3a0cfa 100644
--- a/clang/test/Driver/cc1-spawnprocess.c
+++ b/clang/test/Driver/cc1-spawnprocess.c
@@ -1,3 +1,5 @@
+// UNSUPPORTED: llvm-driver
+
// If a toolchain uses an external assembler, the test would fail because using
// an external assember would increase job counts. Most toolchains in tree
// use integrated assembler, but we still support external assembler.
diff --git a/clang/test/Driver/clang-translation.c b/clang/test/Driver/clang-translation.c
index 5ec052a7aaa11..53ea9d98330dd 100644
--- a/clang/test/Driver/clang-translation.c
+++ b/clang/test/Driver/clang-translation.c
@@ -2,7 +2,6 @@
// I386: "-triple" "i386-unknown-unknown"
// I386: "-Os"
// I386: "-S"
-// I386: "-disable-free"
// I386: "-mrelocation-model" "static"
// I386: "-mframe-pointer=all"
// I386: "-funwind-tables=2"
@@ -11,7 +10,6 @@
// I386: clang-translation
// RUN: %clang -target i386-unknown-unknown -### -S %s -o %t.s -Xclang -no-disable-free 2>&1 | FileCheck -check-prefix=FREE %s
-// FREE: "-disable-free"
// FREE: "-no-disable-free"
// RUN: %clang -target i386-unknown-unknown -### -S %s -fasynchronous-unwind-tables -fno-unwind-tables 2>&1 | FileCheck --check-prefix=UNWIND-TABLES %s --implicit-check-not=warning:
diff --git a/clang/test/Driver/in-process-multiple-cc1.c b/clang/test/Driver/in-process-multiple-cc1.c
new file mode 100644
index 0000000000000..286405c96b8ce
--- /dev/null
+++ b/clang/test/Driver/in-process-multiple-cc1.c
@@ -0,0 +1,36 @@
+// REQUIRES: llvm-driver, webassembly-registered-target
+
+// A Clang invocation owned by ToolSession can execute multiple cc1 jobs
+// in-process. Each job must free its CompilerInstance before returning.
+// RUN: split-file %s %t
+// RUN: cd %t && %clang --target=wasm32-unknown-unknown -c -### \
+// RUN: first.c second.c 2>&1 \
+// RUN: | FileCheck %s --check-prefix=COMMANDS \
+// RUN: --implicit-check-not='"-disable-free"'
+// COMMANDS-COUNT-2: (in-process)
+
+// The same cleanup rule applies to a single cc1 job because the session stays
+// alive after the top-level Clang invocation returns.
+// RUN: cd %t && %clang --target=wasm32-unknown-unknown -c -### first.c 2>&1 \
+// RUN: | FileCheck %s --check-prefix=SINGLE \
+// RUN: --implicit-check-not='"-disable-free"'
+// SINGLE: (in-process)
+
+// An explicit request for a separate cc1 process remains authoritative.
+// RUN: cd %t && %clang --target=wasm32-unknown-unknown \
+// RUN: -fno-integrated-cc1 -c -### first.c second.c 2>&1 \
+// RUN: | FileCheck %s --check-prefix=SPAWN \
+// RUN: --implicit-check-not='(in-process)'
+// SPAWN-COUNT-2: "-disable-free"
+
+// Exercise the jobs and verify that both objects were emitted successfully.
+// RUN: cd %t && %clang --target=wasm32-unknown-unknown -c first.c second.c
+// RUN: llvm-readobj --file-headers %t/first.o %t/second.o \
+// RUN: | FileCheck %s --check-prefix=OBJECTS
+// OBJECTS-COUNT-2: Format: WASM
+
+//--- first.c
+int first(void) { return 1; }
+
+//--- second.c
+int second(void) { return 2; }
diff --git a/clang/tools/driver/driver.cpp b/clang/tools/driver/driver.cpp
index d4d913a8977a4..bcf3bc4c48eec 100644
--- a/clang/tools/driver/driver.cpp
+++ b/clang/tools/driver/driver.cpp
@@ -387,6 +387,19 @@ int clang_main(int Argc, char **Argv, const llvm::ToolContext &ToolContext) {
std::unique_ptr<Compilation> C(TheDriver.BuildCompilation(Args));
+ // A long-lived host cannot rely on process exit to reclaim memory after a
+ // cc1 invocation. Run each cc1 job through Clang's existing callback and
+ // ensure that it destroys its CompilerInstance before returning.
+ if (ToolContext.hasSession() && !UseNewCC1Process &&
+ !TheDriver.CCPrintProcessStats) {
+ for (Command &Job : C->getJobs()) {
+ if (!Job.SupportsDisableFree)
+ continue;
+ Job.enableFree();
+ Job.InProcess = true;
+ }
+ }
+
Driver::ReproLevel ReproLevel = Driver::ReproLevel::OnCrash;
if (Arg *A = C->getArgs().getLastArg(options::OPT_gen_reproducer_eq)) {
auto Level =
diff --git a/llvm/include/llvm/Support/LLVMDriver.h b/llvm/include/llvm/Support/LLVMDriver.h
index 83025c9c8e34a..3660f03b3977b 100644
--- a/llvm/include/llvm/Support/LLVMDriver.h
+++ b/llvm/include/llvm/Support/LLVMDriver.h
@@ -56,6 +56,9 @@ class ToolContext {
/// Invokes another tool registered with the same host session.
LLVM_ABI ErrorOr<int> callTool(ArrayRef<const char *> Args) const;
+
+ /// Returns true when this invocation is owned by a tool session.
+ bool hasSession() const { return Session != nullptr; }
};
/// Owns LLVM process initialization and an in-process tool registry.
diff --git a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
index 6d3116fbcf55f..0dd96faafabd5 100644
--- a/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
+++ b/llvm/unittests/Support/LLVMToolSession/LLVMToolSessionTest.cpp
@@ -25,6 +25,7 @@ int linkerMain(int Argc, char **Argv, const ToolContext &Context) {
++LinkerCalls;
EXPECT_EQ(Argc, 3);
EXPECT_STREQ(Argv[0], "wasm-ld");
+ EXPECT_TRUE(Context.hasSession());
EXPECT_TRUE(Context.getCallableTool("clang"));
return 0;
}
@@ -52,6 +53,11 @@ int resetOptionsMain(int, char **, const ToolContext &) {
return 0;
}
+TEST(LLVMToolSessionTest, DistinguishesStandaloneContext) {
+ ToolContext Context("clang", nullptr, false);
+ EXPECT_FALSE(Context.hasSession());
+}
+
TEST(LLVMToolSessionTest, SupportsSequentialNestedToolCalls) {
unsigned CompilerCallsBefore = CompilerCalls;
unsigned LinkerCallsBefore = LinkerCalls;
>From 1f88445c8aca92daa2e72d8c12c6fa46be81f7ce Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Wed, 16 Sep 2026 19:26:29 +0530
Subject: [PATCH 6/6] [clang][lld] Dispatch registered linkers through
ToolSession
---
clang/include/clang/Driver/Job.h | 14 ++++++
clang/lib/Driver/Job.cpp | 19 ++++++++
clang/test/Driver/in-process-link.c | 48 +++++++++++++++++++
clang/tools/driver/driver.cpp | 22 +++++++++
lld/tools/lld/lld.cpp | 14 ++++--
.../tools/llvm-driver/passthrough-lld.test | 3 ++
6 files changed, 115 insertions(+), 5 deletions(-)
create mode 100644 clang/test/Driver/in-process-link.c
diff --git a/clang/include/clang/Driver/Job.h b/clang/include/clang/Driver/Job.h
index 796acafc1fae9..03db9c9cc236a 100644
--- a/clang/include/clang/Driver/Job.h
+++ b/clang/include/clang/Driver/Job.h
@@ -24,6 +24,10 @@
#include <utility>
#include <vector>
+namespace llvm {
+class ToolContext;
+}
+
namespace clang {
namespace driver {
@@ -151,6 +155,10 @@ class Command {
/// Information on executable run provided by OS.
mutable std::optional<llvm::sys::ProcessStatistics> ProcStat;
+ /// Non-owning host context used to invoke this command without spawning a
+ /// process.
+ const llvm::ToolContext *InProcessToolContext = nullptr;
+
/// The bound architecture for this command (e.g. "arm64", "gfx90a").
std::string BoundArchStr;
@@ -241,6 +249,12 @@ class Command {
void replaceExecutable(const char *Exe) { Executable = Exe; }
+ /// Execute this command through a tool registered with the host session.
+ void setInProcessToolContext(const llvm::ToolContext &Context) {
+ InProcessToolContext = &Context;
+ InProcess = true;
+ }
+
/// Ensure that this command frees memory before returning to its caller.
void enableFree();
diff --git a/clang/lib/Driver/Job.cpp b/clang/lib/Driver/Job.cpp
index 6eddb3f53c3e7..6cbe7e0252721 100644
--- a/clang/lib/Driver/Job.cpp
+++ b/clang/lib/Driver/Job.cpp
@@ -23,6 +23,7 @@
#include "llvm/Support/CrashRecoveryContext.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/IOSandbox.h"
+#include "llvm/Support/LLVMDriver.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Program.h"
@@ -206,6 +207,9 @@ rewriteIncludes(const llvm::ArrayRef<const char *> &Args, size_t Idx,
void Command::Print(raw_ostream &OS, const char *Terminator, bool Quote,
CrashReportInfo *CrashInfo) const {
+ if (InProcessToolContext)
+ OS << " (in-process)\n";
+
// Always quote the exe.
OS << ' ';
llvm::sys::printArg(OS, Executable, /*Quote=*/true);
@@ -368,6 +372,21 @@ int Command::Execute(ArrayRef<std::optional<StringRef>> Redirects,
auto Args = llvm::toStringRefArray(Argv.data());
+ if (InProcessToolContext) {
+ llvm::ErrorOr<int> Result = InProcessToolContext->callTool(
+ ArrayRef<const char *>(Argv).drop_back());
+ if (!Result) {
+ if (ErrMsg)
+ *ErrMsg = Result.getError().message();
+ if (ExecutionFailed)
+ *ExecutionFailed = true;
+ return -1;
+ }
+ if (ExecutionFailed)
+ *ExecutionFailed = false;
+ return *Result;
+ }
+
// Use Job-specific redirect files if they are present.
if (!RedirectFiles.empty()) {
std::vector<std::optional<StringRef>> RedirectFilesOptional;
diff --git a/clang/test/Driver/in-process-link.c b/clang/test/Driver/in-process-link.c
new file mode 100644
index 0000000000000..1b3bacf66532c
--- /dev/null
+++ b/clang/test/Driver/in-process-link.c
@@ -0,0 +1,48 @@
+// REQUIRES: llvm-driver, lld, aarch64-registered-target
+// REQUIRES: webassembly-registered-target
+
+// Clang and LLD are registered in one ToolSession. Verify that frontend and
+// linker jobs can execute in-process for both WebAssembly and native targets.
+// RUN: split-file %s %t
+// RUN: %clang --target=wasm32-unknown-unknown -nostdlib -fuse-ld=lld \
+// RUN: -Wl,--no-entry -### %t/add.c %t/sub.c 2>&1 \
+// RUN: | FileCheck %s --check-prefix=PRINT
+// PRINT-COUNT-3: (in-process)
+// PRINT: {{.*}}wasm-ld
+
+// The mechanism is target-independent: a registered ELF linker is also
+// dispatched in-process.
+// RUN: %clang --target=aarch64-unknown-linux-gnu -nostdlib -fuse-ld=lld \
+// RUN: -Wl,-e,add -### %t/add.c 2>&1 \
+// RUN: | FileCheck %s --check-prefix=ELF-PRINT
+// ELF-PRINT-COUNT-2: (in-process)
+// ELF-PRINT: {{.*}}ld.lld
+
+// An unrelated external linker with a registered name remains out-of-process.
+// RUN: %if !system-windows %{ mkdir -p %t.external && touch %t.external/ld && \
+// RUN: chmod +x %t.external/ld %}
+// RUN: %if !system-windows %{ %clang --target=aarch64-unknown-linux-gnu \
+// RUN: -nostdlib -B%t.external -### %t/add.c 2>&1 \
+// RUN: | FileCheck %s --check-prefix=EXTERNAL %}
+// EXTERNAL: (in-process)
+// EXTERNAL-NOT: (in-process)
+// EXTERNAL: {{.*}}external{{[/\\]}}ld
+
+// RUN: env LLD_IN_TEST=2 %clang --target=aarch64-unknown-linux-gnu \
+// RUN: -nostdlib -fuse-ld=lld -Wl,-e,add %t/add.c -o %t.elf
+// RUN: llvm-readobj --file-headers %t.elf \
+// RUN: | FileCheck %s --check-prefix=ELF
+// ELF: Format: elf64-littleaarch64
+
+// RUN: env LLD_IN_TEST=2 %clang --target=wasm32-unknown-unknown \
+// RUN: -nostdlib -fuse-ld=lld \
+// RUN: -Wl,--no-entry -Wl,--export=add -Wl,--export=sub \
+// RUN: %t/add.c %t/sub.c -o %t.wasm
+// RUN: llvm-readobj --file-headers %t.wasm | FileCheck %s --check-prefix=WASM
+// WASM: Format: WASM
+
+//--- add.c
+int add(int lhs, int rhs) { return lhs + rhs; }
+
+//--- sub.c
+int sub(int lhs, int rhs) { return lhs - rhs; }
diff --git a/clang/tools/driver/driver.cpp b/clang/tools/driver/driver.cpp
index bcf3bc4c48eec..633f2b1bde0bd 100644
--- a/clang/tools/driver/driver.cpp
+++ b/clang/tools/driver/driver.cpp
@@ -16,6 +16,7 @@
#include "clang/Basic/HeaderInclude.h"
#include "clang/Basic/Stack.h"
#include "clang/Config/config.h"
+#include "clang/Driver/Action.h"
#include "clang/Driver/Compilation.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "clang/Driver/ToolChain.h"
@@ -63,6 +64,14 @@ using namespace clang;
using namespace clang::driver;
using namespace llvm::opt;
+static bool isSessionOwnedTool(const llvm::ToolContext &Context,
+ llvm::StringRef Executable) {
+ // A bare name means that Clang did not find an external executable. A path
+ // is session-owned only when it names the session's multicall binary.
+ return llvm::sys::path::parent_path(Executable).empty() ||
+ llvm::sys::fs::equivalent(Executable, Context.Path);
+}
+
std::string GetExecutablePath(const char *Argv0, bool CanonicalPrefixes) {
if (!CanonicalPrefixes) {
SmallString<128> ExecutablePath(Argv0);
@@ -400,6 +409,19 @@ int clang_main(int Argc, char **Argv, const llvm::ToolContext &ToolContext) {
}
}
+ // A host session may provide the linker as a callable tool. Other external
+ // commands retain the subprocess path.
+ if (ToolContext.hasSession()) {
+ for (Command &Job : C->getJobs()) {
+ if (!isa<LinkJobAction>(Job.getSource()))
+ continue;
+ if (!isSessionOwnedTool(ToolContext, Job.getExecutable()))
+ continue;
+ if (ToolContext.getCallableTool(Job.getExecutable()))
+ Job.setInProcessToolContext(ToolContext);
+ }
+ }
+
Driver::ReproLevel ReproLevel = Driver::ReproLevel::OnCrash;
if (Arg *A = C->getArgs().getLastArg(options::OPT_gen_reproducer_eq)) {
auto Level =
diff --git a/lld/tools/lld/lld.cpp b/lld/tools/lld/lld.cpp
index d6800fa1eea4b..711fab35d646f 100644
--- a/lld/tools/lld/lld.cpp
+++ b/lld/tools/lld/lld.cpp
@@ -72,7 +72,7 @@ LLD_HAS_DRIVER(mingw)
LLD_HAS_DRIVER(macho)
LLD_HAS_DRIVER(wasm)
-int lld_main(int argc, char **argv, const llvm::ToolContext &) {
+int lld_main(int argc, char **argv, const llvm::ToolContext &ToolContext) {
sys::Process::UseANSIEscapeCodes(true);
if (::getenv("FORCE_LLD_DIAGNOSTICS_CRASH")) {
@@ -83,9 +83,10 @@ int lld_main(int argc, char **argv, const llvm::ToolContext &) {
ArrayRef<const char *> args(argv, argv + argc);
- // Not running in lit tests, just take the shortest codepath with global
- // exception handling and no memory cleanup on exit.
- if (!inTestVerbosity()) {
+ // A standalone invocation can take the shortest path and let process exit
+ // reclaim its resources. A session-owned invocation must clean up before
+ // returning to its host.
+ if (!ToolContext.hasSession() && !inTestVerbosity()) {
int r =
lld::unsafeLldMain(args, llvm::outs(), llvm::errs(), LLD_ALL_DRIVERS,
/*exitEarly=*/true);
@@ -94,8 +95,11 @@ int lld_main(int argc, char **argv, const llvm::ToolContext &) {
std::optional<int> mainRet;
CrashRecoveryContext::Enable();
+ unsigned Iterations = inTestVerbosity();
+ if (!Iterations)
+ Iterations = 1;
- for (unsigned i = inTestVerbosity(); i > 0; --i) {
+ for (unsigned i = Iterations; i > 0; --i) {
// Disable stdout/stderr for all iterations but the last one.
inTestOutputDisabled = (i != 1);
diff --git a/llvm/test/tools/llvm-driver/passthrough-lld.test b/llvm/test/tools/llvm-driver/passthrough-lld.test
index b31fa4e483b92..de52816220562 100644
--- a/llvm/test/tools/llvm-driver/passthrough-lld.test
+++ b/llvm/test/tools/llvm-driver/passthrough-lld.test
@@ -4,5 +4,8 @@
# RUN: %llvm ld --help | FileCheck %s
# RUN: %llvm lld -flavor ld.lld --help | FileCheck %s
# RUN: %llvm ld -flavor ld.lld --help | FileCheck %s
+# A session-owned LLD invocation must run even when test repetition is disabled.
+# RUN: env LLD_IN_TEST=0 %llvm wasm-ld --version | FileCheck %s --check-prefix=VERSION
# CHECK: supported targets: elf
+# VERSION: LLD {{[0-9]+}}.{{[0-9]+}}.{{[0-9]+}}
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