mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Andrea Gussoni
06733a9f3a
Split the `InlineHelpers` pass into the three phases: - `link-helpers-to-inline` links the missing `revng_inline` helper bodies from the `libtcg-helpers-to-inline-arch` module. - `inline-helpers` inlines, in every function except those tagged `Root` or `Helper`, the calls to `revng_inline` helpers whose critical arguments on the call site are constant. - `delete-helper-bodies` drops from the module the body of every `revng_inline` function, leaving only the declaration. The three passes live in a dedicated `revngInlineHelpers` library (`lib/InlineHelpers/` + `include/revng/InlineHelpers/`), so that libraries which do not depend on `revngFunctionIsolation` can use them without creating cyclic dependencies.
93 lines
3.3 KiB
C++
93 lines
3.3 KiB
C++
//
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// This file is distributed under the MIT License. See LICENSE.md for details.
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//
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#include <memory>
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#include <set>
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#include <string>
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/ADT/StringSet.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Metadata.h"
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#include "llvm/IR/Module.h"
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#include "llvm/Pass.h"
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#include "revng/InlineHelpers/LinkHelpersToInline.h"
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#include "revng/Support/Assert.h"
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#include "revng/Support/IRHelpers.h"
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#include "revng/Support/ResourceFinder.h"
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using namespace llvm;
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char LinkHelpersToInlinePass::ID = 0;
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using Register = RegisterPass<LinkHelpersToInlinePass>;
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static Register X("link-helpers-to-inline",
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"Link Required Helpers To Inline Pass",
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true,
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true);
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bool LinkHelpersToInlinePass::runOnModule(llvm::Module &M) {
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NamedMDNode *Node = M.getNamedMetadata(QemuArchitectureMD);
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revng_assert(Node != nullptr);
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revng_assert(Node->getNumOperands() > 0);
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// Multiple linkings could have lead to this node having more than one
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// operand, if so check that they are all the same.
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llvm::StringSet Strings;
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for (size_t I = 0; I < Node->getNumOperands(); I++) {
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revng_assert(Node->getOperand(0)->getNumOperands() == 1);
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const MDOperand &StringNode = Node->getOperand(0)->getOperand(0);
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Strings.insert(cast<MDString>(StringNode)->getString());
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}
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revng_assert(Strings.size() == 1,
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"QEMU helpers of multiple architectures were linked inside the "
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"module");
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// Collect the names of revng_inline helpers that lack a body in `M` and
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// therefore need to be cloned from the per-architecture to-inline bitcode.
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SmallVector<StringRef, 32> MissingBodies;
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for (llvm::Function &F : M) {
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if (F.isDeclaration() and F.getSection() == InlineHelpersSection) {
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MissingBodies.push_back(F.getName());
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}
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}
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// Nothing to link — every referenced revng_inline helper already has a
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// body in `M`. Skip the expensive bitcode parse + clone + link in this case.
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if (MissingBodies.empty()) {
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return true;
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}
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// Given the architecture MD, retrieve the correct libtcg module and link
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// it into the main module.
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StringRef ArchName = Strings.begin()->first();
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const std::string LibHelpersName = ("/share/revng/"
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"libtcg-helpers-to-inline-"
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+ ArchName + ".bc")
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.str();
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auto OptionalHelpers = revng::ResourceFinder.findFile(LibHelpersName);
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revng_assert(OptionalHelpers.has_value(), "Cannot find libtcg helpers");
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std::unique_ptr<llvm::Module>
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HelpersModule = parseIR(M.getContext(), OptionalHelpers.value());
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std::set<const llvm::Function *> ToClone;
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for (StringRef Name : MissingBodies) {
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llvm::Function *HelperFunction = HelpersModule->getFunction(Name);
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revng_assert(HelperFunction != nullptr
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and not HelperFunction->isDeclaration(),
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"revng_inline helper missing body in to-inline.bc; the "
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"static-policy / slim-down chain produced an "
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"inconsistent state");
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ToClone.insert(HelperFunction);
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}
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auto ClonedHelpersModule = ::cloneFiltered(*HelpersModule, ToClone);
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linkModules(std::move(ClonedHelpersModule), M);
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return true;
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}
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