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[Clang] Add codegen option to add passbuilder callback functions (#70171
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wsmoses authored Nov 7, 2023
1 parent 23099ac commit 3c11ac5
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Showing 8 changed files with 116 additions and 0 deletions.
1 change: 1 addition & 0 deletions clang/examples/CMakeLists.txt
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Expand Up @@ -4,6 +4,7 @@ if(NOT CLANG_BUILD_EXAMPLES)
endif()

if(CLANG_PLUGIN_SUPPORT)
add_subdirectory(LLVMPrintFunctionNames)
add_subdirectory(PrintFunctionNames)
add_subdirectory(AnnotateFunctions)
add_subdirectory(Attribute)
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23 changes: 23 additions & 0 deletions clang/examples/LLVMPrintFunctionNames/CMakeLists.txt
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@@ -0,0 +1,23 @@
# If we don't need RTTI or EH, there's no reason to export anything
# from the plugin.
if(NOT MSVC) # MSVC mangles symbols differently, and
# PrintLLVMFunctionNames.export contains C++ symbols.
if(NOT LLVM_REQUIRES_RTTI)
if(NOT LLVM_REQUIRES_EH)
set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/LLVMPrintFunctionNames.exports)
endif()
endif()
endif()

add_llvm_library(LLVMPrintFunctionNames MODULE LLVMPrintFunctionNames.cpp PLUGIN_TOOL clang)

if(WIN32 OR CYGWIN)
set(LLVM_LINK_COMPONENTS
Support
)
clang_target_link_libraries(LLVMPrintFunctionNames PRIVATE
clangAST
clangBasic
clangFrontend
)
endif()
78 changes: 78 additions & 0 deletions clang/examples/LLVMPrintFunctionNames/LLVMPrintFunctionNames.cpp
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@@ -0,0 +1,78 @@
//===- LLVMPrintFunctionNames.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
//
//===----------------------------------------------------------------------===//
//
// Example clang plugin which simply prints the names of all the functions
// within the generated LLVM code.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/AST.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendPluginRegistry.h"
#include "clang/Sema/Sema.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Passes/OptimizationLevel.h"
#include "llvm/Passes/PassBuilder.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;

namespace {

class PrintPass final : public llvm::AnalysisInfoMixin<PrintPass> {
friend struct llvm::AnalysisInfoMixin<PrintPass>;

private:
static llvm::AnalysisKey key;

public:
using Result = llvm::PreservedAnalyses;

Result run(llvm::Module &M, llvm::ModuleAnalysisManager &MAM) {
for (auto &F : M)
llvm::outs() << "[PrintPass] Found function: " << F.getName() << "\n";
return llvm::PreservedAnalyses::all();
}
static bool isRequired() { return true; }
};

void PrintCallback(llvm::PassBuilder &PB) {
PB.registerPipelineStartEPCallback(
[](llvm::ModulePassManager &MPM, llvm::OptimizationLevel) {
MPM.addPass(PrintPass());
});
}

class LLVMPrintFunctionsConsumer : public ASTConsumer {
public:
LLVMPrintFunctionsConsumer(CompilerInstance &Instance) {
Instance.getCodeGenOpts().PassBuilderCallbacks.push_back(PrintCallback);
}
};

class LLVMPrintFunctionNamesAction : public PluginASTAction {
protected:
std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
llvm::StringRef) override {
return std::make_unique<LLVMPrintFunctionsConsumer>(CI);
}
bool ParseArgs(const CompilerInstance &,
const std::vector<std::string> &) override {
return true;
}
PluginASTAction::ActionType getActionType() override {
return AddBeforeMainAction;
}
};

} // namespace

static FrontendPluginRegistry::Add<LLVMPrintFunctionNamesAction>
X("llvm-print-fns", "print function names, llvm level");
Empty file.
6 changes: 6 additions & 0 deletions clang/include/clang/Basic/CodeGenOptions.h
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Expand Up @@ -26,6 +26,9 @@
#include <string>
#include <vector>

namespace llvm {
class PassBuilder;
}
namespace clang {

/// Bitfields of CodeGenOptions, split out from CodeGenOptions to ensure
Expand Down Expand Up @@ -408,6 +411,9 @@ class CodeGenOptions : public CodeGenOptionsBase {
/// List of dynamic shared object files to be loaded as pass plugins.
std::vector<std::string> PassPlugins;

/// List of pass builder callbacks.
std::vector<std::function<void(llvm::PassBuilder &)>> PassBuilderCallbacks;

/// Path to allowlist file specifying which objects
/// (files, functions) should exclusively be instrumented
/// by sanitizer coverage pass.
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2 changes: 2 additions & 0 deletions clang/lib/CodeGen/BackendUtil.cpp
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Expand Up @@ -908,6 +908,8 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
<< PluginFN << toString(PassPlugin.takeError());
}
}
for (auto PassCallback : CodeGenOpts.PassBuilderCallbacks)
PassCallback(PB);
#define HANDLE_EXTENSION(Ext) \
get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
#include "llvm/Support/Extension.def"
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1 change: 1 addition & 0 deletions clang/test/CMakeLists.txt
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Expand Up @@ -100,6 +100,7 @@ if(CLANG_BUILD_EXAMPLES AND CLANG_PLUGIN_SUPPORT)
CallSuperAttr
PluginsOrder
PrintFunctionNames
LLVMPrintFunctionNames
)
endif ()

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5 changes: 5 additions & 0 deletions clang/test/Frontend/llvmplugins.c
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@@ -0,0 +1,5 @@
// RUN: %clang_cc1 -load %llvmshlibdir/LLVMPrintFunctionNames%pluginext -S -o /dev/null -emit-llvm %s 2>&1 | FileCheck %s
// REQUIRES: plugins, examples

// CHECK: [PrintPass] Found function: x
int x(int y){ return y; }

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