mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Alvise de Faveri
122 lines
3.1 KiB
C++
122 lines
3.1 KiB
C++
//
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// Copyright rev.ng Labs Srl. See LICENSE.md for details.
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//
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Instruction.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/Value.h"
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#include "llvm/Support/Casting.h"
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#include "revng/ADT/RecursiveCoroutine.h"
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#include "revng/Support/FunctionTags.h"
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#include "revng/Support/IRHelpers.h"
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#include "revng-c/Backend/VariableScopeAnalysis.h"
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#include "revng-c/RestructureCFG/ASTNode.h"
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#include "revng-c/RestructureCFG/ASTTree.h"
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#include "revng-c/Support/FunctionTags.h"
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using ValuePtrSet = llvm::SmallPtrSet<const llvm::Instruction *, 32>;
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using llvm::BasicBlock;
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using llvm::CallInst;
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using llvm::Function;
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using llvm::Instruction;
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using llvm::User;
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using llvm::any_of;
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using llvm::cast;
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/// Visit the node and all its children recursively, checking if a loop
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/// variable is needed.
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// TODO: This could be precomputed and attached to the SCS node in the GHAST.
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static RecursiveCoroutine<bool> needsLoopVar(ASTNode *N) {
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if (N == nullptr)
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rc_return false;
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auto Kind = N->getKind();
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switch (Kind) {
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case ASTNode::NodeKind::NK_Break:
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case ASTNode::NodeKind::NK_SwitchBreak:
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case ASTNode::NodeKind::NK_Continue:
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case ASTNode::NodeKind::NK_Code:
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rc_return false;
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break;
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case ASTNode::NodeKind::NK_If: {
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IfNode *If = cast<IfNode>(N);
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if (nullptr != If->getThen())
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if (rc_recur needsLoopVar(If->getThen()))
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rc_return true;
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if (If->hasElse())
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if (rc_recur needsLoopVar(If->getElse()))
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rc_return true;
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rc_return false;
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} break;
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case ASTNode::NodeKind::NK_Scs: {
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ScsNode *LoopBody = cast<ScsNode>(N);
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rc_return rc_recur needsLoopVar(LoopBody->getBody());
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} break;
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case ASTNode::NodeKind::NK_List: {
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SequenceNode *Seq = cast<SequenceNode>(N);
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for (ASTNode *Child : Seq->nodes())
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if (rc_recur needsLoopVar(Child))
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rc_return true;
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rc_return false;
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} break;
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case ASTNode::NodeKind::NK_Switch: {
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SwitchNode *Switch = cast<SwitchNode>(N);
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llvm::Value *SwitchVar = Switch->getCondition();
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if (not SwitchVar)
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rc_return true;
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for (const auto &[Labels, CaseNode] : Switch->cases())
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if (rc_recur needsLoopVar(CaseNode))
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rc_return true;
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if (auto *Default = Switch->getDefault())
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if (rc_recur needsLoopVar(Default))
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rc_return true;
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rc_return false;
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} break;
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case ASTNode::NodeKind::NK_Set: {
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rc_return true;
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} break;
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}
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}
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bool hasLoopDispatchers(const ASTTree &GHAST) {
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return needsLoopVar(GHAST.getRoot());
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}
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ValuePtrSet collectTopScopeVariables(const Function &F) {
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ValuePtrSet TopScopeVars;
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for (const BasicBlock &BB : F) {
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for (const Instruction &I : BB) {
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// We always want to put the stack frame among the top-scope variables,
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// since it is is logical for it to appear at the top of the function even
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// if it is used only in a later scope.
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if (isCallTo(&I, "revng_stack_frame") or needsTopScopeDeclaration(I))
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TopScopeVars.insert(&I);
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}
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}
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return TopScopeVars;
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}
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