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llvm-project/clang/lib/Analysis/CodeInjector.cpp

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Add support for the static analyzer to synthesize function implementations from external model files. Currently the analyzer lazily models some functions using 'BodyFarm', which constructs a fake function implementation that the analyzer can simulate that approximates the semantics of the function when it is called. BodyFarm does this by constructing the AST for such definitions on-the-fly. One strength of BodyFarm is that all symbols and types referenced by synthesized function bodies are contextual adapted to the containing translation unit. The downside is that these ASTs are hardcoded in Clang's own source code. A more scalable model is to allow these models to be defined as source code in separate "model" files and have the analyzer use those definitions lazily when a function body is needed. Among other things, it will allow more customization of the analyzer for specific APIs and platforms. This patch provides the initial infrastructure for this feature. It extends BodyFarm to use an abstract API 'CodeInjector' that can be used to synthesize function bodies. That 'CodeInjector' is implemented using a new 'ModelInjector' in libFrontend, which lazily parses a model file and injects the ASTs into the current translation unit. Models are currently found by specifying a 'model-path' as an analyzer option; if no path is specified the CodeInjector is not used, thus defaulting to the current behavior in the analyzer. Models currently contain a single function definition, and can be found by finding the file <function name>.model. This is an initial starting point for something more rich, but it bootstraps this feature for future evolution. This patch was contributed by Gábor Horváth as part of his Google Summer of Code project. Some notes: - This introduces the notion of a "model file" into FrontendAction and the Preprocessor. This nomenclature is specific to the static analyzer, but possibly could be generalized. Essentially these are sources pulled in exogenously from the principal translation. Preprocessor gets a 'InitializeForModelFile' and 'FinalizeForModelFile' which could possibly be hoisted out of Preprocessor if Preprocessor exposed a new API to change the PragmaHandlers and some other internal pieces. This can be revisited. FrontendAction gets a 'isModelParsingAction()' predicate function used to allow a new FrontendAction to recycle the Preprocessor and ASTContext. This name could probably be made something more general (i.e., not tied to 'model files') at the expense of losing the intent of why it exists. This can be revisited. - This is a moderate sized patch; it has gone through some amount of offline code review. Most of the changes to the non-analyzer parts are fairly small, and would make little sense without the analyzer changes. - Most of the analyzer changes are plumbing, with the interesting behavior being introduced by ModelInjector.cpp and ModelConsumer.cpp. - The new functionality introduced by this change is off-by-default. It requires an analyzer config option to enable. llvm-svn: 216550
2014-08-27 15:14:15 +00:00
//===-- CodeInjector.cpp ----------------------------------------*- C++ -*-===//
//
Update the file headers across all of the LLVM projects in the monorepo to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
2019-01-19 08:50:56 +00:00
// 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
Add support for the static analyzer to synthesize function implementations from external model files. Currently the analyzer lazily models some functions using 'BodyFarm', which constructs a fake function implementation that the analyzer can simulate that approximates the semantics of the function when it is called. BodyFarm does this by constructing the AST for such definitions on-the-fly. One strength of BodyFarm is that all symbols and types referenced by synthesized function bodies are contextual adapted to the containing translation unit. The downside is that these ASTs are hardcoded in Clang's own source code. A more scalable model is to allow these models to be defined as source code in separate "model" files and have the analyzer use those definitions lazily when a function body is needed. Among other things, it will allow more customization of the analyzer for specific APIs and platforms. This patch provides the initial infrastructure for this feature. It extends BodyFarm to use an abstract API 'CodeInjector' that can be used to synthesize function bodies. That 'CodeInjector' is implemented using a new 'ModelInjector' in libFrontend, which lazily parses a model file and injects the ASTs into the current translation unit. Models are currently found by specifying a 'model-path' as an analyzer option; if no path is specified the CodeInjector is not used, thus defaulting to the current behavior in the analyzer. Models currently contain a single function definition, and can be found by finding the file <function name>.model. This is an initial starting point for something more rich, but it bootstraps this feature for future evolution. This patch was contributed by Gábor Horváth as part of his Google Summer of Code project. Some notes: - This introduces the notion of a "model file" into FrontendAction and the Preprocessor. This nomenclature is specific to the static analyzer, but possibly could be generalized. Essentially these are sources pulled in exogenously from the principal translation. Preprocessor gets a 'InitializeForModelFile' and 'FinalizeForModelFile' which could possibly be hoisted out of Preprocessor if Preprocessor exposed a new API to change the PragmaHandlers and some other internal pieces. This can be revisited. FrontendAction gets a 'isModelParsingAction()' predicate function used to allow a new FrontendAction to recycle the Preprocessor and ASTContext. This name could probably be made something more general (i.e., not tied to 'model files') at the expense of losing the intent of why it exists. This can be revisited. - This is a moderate sized patch; it has gone through some amount of offline code review. Most of the changes to the non-analyzer parts are fairly small, and would make little sense without the analyzer changes. - Most of the analyzer changes are plumbing, with the interesting behavior being introduced by ModelInjector.cpp and ModelConsumer.cpp. - The new functionality introduced by this change is off-by-default. It requires an analyzer config option to enable. llvm-svn: 216550
2014-08-27 15:14:15 +00:00
//
//===----------------------------------------------------------------------===//
#include "clang/Analysis/CodeInjector.h"
using namespace clang;
Roll-back r250822. Summary: It breaks the build for the ASTMatchers Subscribers: klimek, cfe-commits Differential Revision: http://reviews.llvm.org/D13893 llvm-svn: 250827
2015-10-20 13:23:58 +00:00
CodeInjector::CodeInjector() {}
CodeInjector::~CodeInjector() {}
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