566 lines
18 KiB
C++
566 lines
18 KiB
C++
//===- SymbolRewriter.cpp - Symbol Rewriter ---------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// SymbolRewriter is a LLVM pass which can rewrite symbols transparently within
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// existing code. It is implemented as a compiler pass and is configured via a
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// YAML configuration file.
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//
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// The YAML configuration file format is as follows:
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//
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// RewriteMapFile := RewriteDescriptors
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// RewriteDescriptors := RewriteDescriptor | RewriteDescriptors
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// RewriteDescriptor := RewriteDescriptorType ':' '{' RewriteDescriptorFields '}'
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// RewriteDescriptorFields := RewriteDescriptorField | RewriteDescriptorFields
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// RewriteDescriptorField := FieldIdentifier ':' FieldValue ','
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// RewriteDescriptorType := Identifier
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// FieldIdentifier := Identifier
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// FieldValue := Identifier
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// Identifier := [0-9a-zA-Z]+
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//
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// Currently, the following descriptor types are supported:
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//
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// - function: (function rewriting)
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// + Source (original name of the function)
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// + Target (explicit transformation)
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// + Transform (pattern transformation)
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// + Naked (boolean, whether the function is undecorated)
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// - global variable: (external linkage global variable rewriting)
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// + Source (original name of externally visible variable)
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// + Target (explicit transformation)
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// + Transform (pattern transformation)
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// - global alias: (global alias rewriting)
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// + Source (original name of the aliased name)
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// + Target (explicit transformation)
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// + Transform (pattern transformation)
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//
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// Note that source and exactly one of [Target, Transform] must be provided
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//
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// New rewrite descriptors can be created. Addding a new rewrite descriptor
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// involves:
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//
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// a) extended the rewrite descriptor kind enumeration
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// (<anonymous>::RewriteDescriptor::RewriteDescriptorType)
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// b) implementing the new descriptor
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// (c.f. <anonymous>::ExplicitRewriteFunctionDescriptor)
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// c) extending the rewrite map parser
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// (<anonymous>::RewriteMapParser::parseEntry)
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//
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// Specify to rewrite the symbols using the `-rewrite-symbols` option, and
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// specify the map file to use for the rewriting via the `-rewrite-map-file`
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// option.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "symbol-rewriter"
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#include "llvm/Transforms/Utils/SymbolRewriter.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/IR/LegacyPassManager.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Support/Regex.h"
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#include "llvm/Support/SourceMgr.h"
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#include "llvm/Support/YAMLParser.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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using namespace SymbolRewriter;
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static cl::list<std::string> RewriteMapFiles("rewrite-map-file",
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cl::desc("Symbol Rewrite Map"),
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cl::value_desc("filename"));
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static void rewriteComdat(Module &M, GlobalObject *GO,
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const std::string &Source,
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const std::string &Target) {
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if (Comdat *CD = GO->getComdat()) {
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auto &Comdats = M.getComdatSymbolTable();
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Comdat *C = M.getOrInsertComdat(Target);
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C->setSelectionKind(CD->getSelectionKind());
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GO->setComdat(C);
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Comdats.erase(Comdats.find(Source));
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}
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}
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namespace {
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template <RewriteDescriptor::Type DT, typename ValueType,
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ValueType *(llvm::Module::*Get)(StringRef) const>
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class ExplicitRewriteDescriptor : public RewriteDescriptor {
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public:
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const std::string Source;
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const std::string Target;
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ExplicitRewriteDescriptor(StringRef S, StringRef T, const bool Naked)
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: RewriteDescriptor(DT), Source(Naked ? StringRef("\01" + S.str()) : S),
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Target(T) {}
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bool performOnModule(Module &M) override;
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static bool classof(const RewriteDescriptor *RD) {
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return RD->getType() == DT;
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}
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};
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template <RewriteDescriptor::Type DT, typename ValueType,
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ValueType *(llvm::Module::*Get)(StringRef) const>
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bool ExplicitRewriteDescriptor<DT, ValueType, Get>::performOnModule(Module &M) {
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bool Changed = false;
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if (ValueType *S = (M.*Get)(Source)) {
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if (GlobalObject *GO = dyn_cast<GlobalObject>(S))
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rewriteComdat(M, GO, Source, Target);
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if (Value *T = (M.*Get)(Target))
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S->setValueName(T->getValueName());
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else
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S->setName(Target);
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Changed = true;
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}
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return Changed;
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}
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template <RewriteDescriptor::Type DT, typename ValueType,
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ValueType *(llvm::Module::*Get)(StringRef) const,
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iterator_range<typename iplist<ValueType>::iterator>
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(llvm::Module::*Iterator)()>
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class PatternRewriteDescriptor : public RewriteDescriptor {
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public:
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const std::string Pattern;
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const std::string Transform;
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PatternRewriteDescriptor(StringRef P, StringRef T)
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: RewriteDescriptor(DT), Pattern(P), Transform(T) { }
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bool performOnModule(Module &M) override;
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static bool classof(const RewriteDescriptor *RD) {
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return RD->getType() == DT;
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}
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};
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template <RewriteDescriptor::Type DT, typename ValueType,
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ValueType *(llvm::Module::*Get)(StringRef) const,
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iterator_range<typename iplist<ValueType>::iterator>
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(llvm::Module::*Iterator)()>
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bool PatternRewriteDescriptor<DT, ValueType, Get, Iterator>::
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performOnModule(Module &M) {
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bool Changed = false;
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for (auto &C : (M.*Iterator)()) {
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std::string Error;
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std::string Name = Regex(Pattern).sub(Transform, C.getName(), &Error);
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if (!Error.empty())
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report_fatal_error("unable to transforn " + C.getName() + " in " +
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M.getModuleIdentifier() + ": " + Error);
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if (C.getName() == Name)
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continue;
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if (GlobalObject *GO = dyn_cast<GlobalObject>(&C))
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rewriteComdat(M, GO, C.getName(), Name);
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if (Value *V = (M.*Get)(Name))
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C.setValueName(V->getValueName());
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else
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C.setName(Name);
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Changed = true;
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}
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return Changed;
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}
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/// Represents a rewrite for an explicitly named (function) symbol. Both the
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/// source function name and target function name of the transformation are
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/// explicitly spelt out.
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typedef ExplicitRewriteDescriptor<RewriteDescriptor::Type::Function,
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llvm::Function, &llvm::Module::getFunction>
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ExplicitRewriteFunctionDescriptor;
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/// Represents a rewrite for an explicitly named (global variable) symbol. Both
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/// the source variable name and target variable name are spelt out. This
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/// applies only to module level variables.
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typedef ExplicitRewriteDescriptor<RewriteDescriptor::Type::GlobalVariable,
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llvm::GlobalVariable,
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&llvm::Module::getGlobalVariable>
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ExplicitRewriteGlobalVariableDescriptor;
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/// Represents a rewrite for an explicitly named global alias. Both the source
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/// and target name are explicitly spelt out.
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typedef ExplicitRewriteDescriptor<RewriteDescriptor::Type::NamedAlias,
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llvm::GlobalAlias,
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&llvm::Module::getNamedAlias>
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ExplicitRewriteNamedAliasDescriptor;
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/// Represents a rewrite for a regular expression based pattern for functions.
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/// A pattern for the function name is provided and a transformation for that
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/// pattern to determine the target function name create the rewrite rule.
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typedef PatternRewriteDescriptor<RewriteDescriptor::Type::Function,
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llvm::Function, &llvm::Module::getFunction,
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&llvm::Module::functions>
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PatternRewriteFunctionDescriptor;
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/// Represents a rewrite for a global variable based upon a matching pattern.
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/// Each global variable matching the provided pattern will be transformed as
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/// described in the transformation pattern for the target. Applies only to
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/// module level variables.
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typedef PatternRewriteDescriptor<RewriteDescriptor::Type::GlobalVariable,
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llvm::GlobalVariable,
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&llvm::Module::getGlobalVariable,
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&llvm::Module::globals>
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PatternRewriteGlobalVariableDescriptor;
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/// PatternRewriteNamedAliasDescriptor - represents a rewrite for global
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/// aliases which match a given pattern. The provided transformation will be
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/// applied to each of the matching names.
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typedef PatternRewriteDescriptor<RewriteDescriptor::Type::NamedAlias,
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llvm::GlobalAlias,
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&llvm::Module::getNamedAlias,
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&llvm::Module::aliases>
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PatternRewriteNamedAliasDescriptor;
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} // namespace
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bool RewriteMapParser::parse(const std::string &MapFile,
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RewriteDescriptorList *DL) {
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ErrorOr<std::unique_ptr<MemoryBuffer>> Mapping =
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MemoryBuffer::getFile(MapFile);
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if (!Mapping)
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report_fatal_error("unable to read rewrite map '" + MapFile + "': " +
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Mapping.getError().message());
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if (!parse(*Mapping, DL))
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report_fatal_error("unable to parse rewrite map '" + MapFile + "'");
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return true;
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}
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bool RewriteMapParser::parse(std::unique_ptr<MemoryBuffer> &MapFile,
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RewriteDescriptorList *DL) {
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SourceMgr SM;
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yaml::Stream YS(MapFile->getBuffer(), SM);
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for (auto &Document : YS) {
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yaml::MappingNode *DescriptorList;
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// ignore empty documents
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if (isa<yaml::NullNode>(Document.getRoot()))
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continue;
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DescriptorList = dyn_cast<yaml::MappingNode>(Document.getRoot());
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if (!DescriptorList) {
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YS.printError(Document.getRoot(), "DescriptorList node must be a map");
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return false;
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}
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for (auto &Descriptor : *DescriptorList)
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if (!parseEntry(YS, Descriptor, DL))
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return false;
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}
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return true;
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}
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bool RewriteMapParser::parseEntry(yaml::Stream &YS, yaml::KeyValueNode &Entry,
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RewriteDescriptorList *DL) {
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yaml::ScalarNode *Key;
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yaml::MappingNode *Value;
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SmallString<32> KeyStorage;
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StringRef RewriteType;
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Key = dyn_cast<yaml::ScalarNode>(Entry.getKey());
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if (!Key) {
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YS.printError(Entry.getKey(), "rewrite type must be a scalar");
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return false;
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}
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Value = dyn_cast<yaml::MappingNode>(Entry.getValue());
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if (!Value) {
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YS.printError(Entry.getValue(), "rewrite descriptor must be a map");
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return false;
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}
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RewriteType = Key->getValue(KeyStorage);
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if (RewriteType.equals("function"))
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return parseRewriteFunctionDescriptor(YS, Key, Value, DL);
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else if (RewriteType.equals("global variable"))
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return parseRewriteGlobalVariableDescriptor(YS, Key, Value, DL);
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else if (RewriteType.equals("global alias"))
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return parseRewriteGlobalAliasDescriptor(YS, Key, Value, DL);
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YS.printError(Entry.getKey(), "unknown rewrite type");
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return false;
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}
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bool RewriteMapParser::
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parseRewriteFunctionDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
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yaml::MappingNode *Descriptor,
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RewriteDescriptorList *DL) {
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bool Naked = false;
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std::string Source;
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std::string Target;
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std::string Transform;
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for (auto &Field : *Descriptor) {
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yaml::ScalarNode *Key;
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yaml::ScalarNode *Value;
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SmallString<32> KeyStorage;
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SmallString<32> ValueStorage;
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StringRef KeyValue;
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Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
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if (!Key) {
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YS.printError(Field.getKey(), "descriptor key must be a scalar");
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return false;
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}
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Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
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if (!Value) {
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YS.printError(Field.getValue(), "descriptor value must be a scalar");
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return false;
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}
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KeyValue = Key->getValue(KeyStorage);
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if (KeyValue.equals("source")) {
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std::string Error;
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Source = Value->getValue(ValueStorage);
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if (!Regex(Source).isValid(Error)) {
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YS.printError(Field.getKey(), "invalid regex: " + Error);
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return false;
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}
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} else if (KeyValue.equals("target")) {
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Target = Value->getValue(ValueStorage);
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} else if (KeyValue.equals("transform")) {
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Transform = Value->getValue(ValueStorage);
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} else if (KeyValue.equals("naked")) {
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std::string Undecorated;
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Undecorated = Value->getValue(ValueStorage);
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Naked = StringRef(Undecorated).lower() == "true" || Undecorated == "1";
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} else {
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YS.printError(Field.getKey(), "unknown key for function");
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return false;
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}
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}
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if (Transform.empty() == Target.empty()) {
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YS.printError(Descriptor,
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"exactly one of transform or target must be specified");
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return false;
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}
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// TODO see if there is a more elegant solution to selecting the rewrite
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// descriptor type
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if (!Target.empty())
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DL->push_back(llvm::make_unique<ExplicitRewriteFunctionDescriptor>(
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Source, Target, Naked));
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else
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DL->push_back(
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llvm::make_unique<PatternRewriteFunctionDescriptor>(Source, Transform));
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return true;
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}
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bool RewriteMapParser::
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parseRewriteGlobalVariableDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
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yaml::MappingNode *Descriptor,
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RewriteDescriptorList *DL) {
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std::string Source;
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std::string Target;
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std::string Transform;
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for (auto &Field : *Descriptor) {
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yaml::ScalarNode *Key;
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yaml::ScalarNode *Value;
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SmallString<32> KeyStorage;
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SmallString<32> ValueStorage;
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StringRef KeyValue;
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Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
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if (!Key) {
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YS.printError(Field.getKey(), "descriptor Key must be a scalar");
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return false;
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}
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Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
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if (!Value) {
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YS.printError(Field.getValue(), "descriptor value must be a scalar");
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return false;
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}
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KeyValue = Key->getValue(KeyStorage);
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if (KeyValue.equals("source")) {
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std::string Error;
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Source = Value->getValue(ValueStorage);
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if (!Regex(Source).isValid(Error)) {
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YS.printError(Field.getKey(), "invalid regex: " + Error);
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return false;
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}
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} else if (KeyValue.equals("target")) {
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Target = Value->getValue(ValueStorage);
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} else if (KeyValue.equals("transform")) {
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Transform = Value->getValue(ValueStorage);
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} else {
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YS.printError(Field.getKey(), "unknown Key for Global Variable");
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return false;
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}
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}
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if (Transform.empty() == Target.empty()) {
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YS.printError(Descriptor,
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"exactly one of transform or target must be specified");
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return false;
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}
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if (!Target.empty())
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DL->push_back(llvm::make_unique<ExplicitRewriteGlobalVariableDescriptor>(
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Source, Target,
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/*Naked*/ false));
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else
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DL->push_back(llvm::make_unique<PatternRewriteGlobalVariableDescriptor>(
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Source, Transform));
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return true;
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}
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bool RewriteMapParser::
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parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
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yaml::MappingNode *Descriptor,
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RewriteDescriptorList *DL) {
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std::string Source;
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std::string Target;
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std::string Transform;
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for (auto &Field : *Descriptor) {
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yaml::ScalarNode *Key;
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yaml::ScalarNode *Value;
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SmallString<32> KeyStorage;
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SmallString<32> ValueStorage;
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StringRef KeyValue;
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Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
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if (!Key) {
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YS.printError(Field.getKey(), "descriptor key must be a scalar");
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return false;
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}
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Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
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if (!Value) {
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YS.printError(Field.getValue(), "descriptor value must be a scalar");
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return false;
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}
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KeyValue = Key->getValue(KeyStorage);
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if (KeyValue.equals("source")) {
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std::string Error;
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Source = Value->getValue(ValueStorage);
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if (!Regex(Source).isValid(Error)) {
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YS.printError(Field.getKey(), "invalid regex: " + Error);
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return false;
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}
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} else if (KeyValue.equals("target")) {
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Target = Value->getValue(ValueStorage);
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} else if (KeyValue.equals("transform")) {
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Transform = Value->getValue(ValueStorage);
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} else {
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YS.printError(Field.getKey(), "unknown key for Global Alias");
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return false;
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}
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}
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if (Transform.empty() == Target.empty()) {
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YS.printError(Descriptor,
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"exactly one of transform or target must be specified");
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return false;
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}
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if (!Target.empty())
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DL->push_back(llvm::make_unique<ExplicitRewriteNamedAliasDescriptor>(
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Source, Target,
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/*Naked*/ false));
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else
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DL->push_back(llvm::make_unique<PatternRewriteNamedAliasDescriptor>(
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Source, Transform));
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return true;
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}
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namespace {
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class RewriteSymbolsLegacyPass : public ModulePass {
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public:
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static char ID; // Pass identification, replacement for typeid
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|
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RewriteSymbolsLegacyPass();
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RewriteSymbolsLegacyPass(SymbolRewriter::RewriteDescriptorList &DL);
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bool runOnModule(Module &M) override;
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private:
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RewriteSymbolPass Impl;
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};
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char RewriteSymbolsLegacyPass::ID = 0;
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RewriteSymbolsLegacyPass::RewriteSymbolsLegacyPass() : ModulePass(ID), Impl() {
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initializeRewriteSymbolsLegacyPassPass(*PassRegistry::getPassRegistry());
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}
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RewriteSymbolsLegacyPass::RewriteSymbolsLegacyPass(
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SymbolRewriter::RewriteDescriptorList &DL)
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: ModulePass(ID), Impl(DL) {}
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bool RewriteSymbolsLegacyPass::runOnModule(Module &M) {
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return Impl.runImpl(M);
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}
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}
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namespace llvm {
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PreservedAnalyses RewriteSymbolPass::run(Module &M, ModuleAnalysisManager &AM) {
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if (!runImpl(M))
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return PreservedAnalyses::all();
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return PreservedAnalyses::none();
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}
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|
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bool RewriteSymbolPass::runImpl(Module &M) {
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bool Changed;
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Changed = false;
|
|
for (auto &Descriptor : Descriptors)
|
|
Changed |= Descriptor->performOnModule(M);
|
|
|
|
return Changed;
|
|
}
|
|
|
|
void RewriteSymbolPass::loadAndParseMapFiles() {
|
|
const std::vector<std::string> MapFiles(RewriteMapFiles);
|
|
SymbolRewriter::RewriteMapParser Parser;
|
|
|
|
for (const auto &MapFile : MapFiles)
|
|
Parser.parse(MapFile, &Descriptors);
|
|
}
|
|
}
|
|
|
|
INITIALIZE_PASS(RewriteSymbolsLegacyPass, "rewrite-symbols", "Rewrite Symbols",
|
|
false, false)
|
|
|
|
ModulePass *llvm::createRewriteSymbolsPass() {
|
|
return new RewriteSymbolsLegacyPass();
|
|
}
|
|
|
|
ModulePass *
|
|
llvm::createRewriteSymbolsPass(SymbolRewriter::RewriteDescriptorList &DL) {
|
|
return new RewriteSymbolsLegacyPass(DL);
|
|
}
|