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[clang-tidy]improve performance-unnecessary-value-param performance #128383

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Merged
HerrCai0907 merged 2 commits into from
Feb 26, 2025
Merged

[clang-tidy]improve performance-unnecessary-value-param performance #128383

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721393e
[clang-tidy]improve performance-unnecessary-value-param performance
HerrCai0907 Feb 23, 2025
ec04d45
note break build in doc
HerrCai0907 Feb 24, 2025
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14 changes: 1 addition & 13 deletions clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,6 @@
//===----------------------------------------------------------------------===//

#include "UnnecessaryValueParamCheck.h"

#include "../utils/DeclRefExprUtils.h"
#include "../utils/FixItHintUtils.h"
#include "../utils/Matchers.h"
Expand All @@ -30,14 +29,6 @@ std::string paramNameOrIndex(StringRef Name, size_t Index) {
.str();
}

bool isReferencedOutsideOfCallExpr(const FunctionDecl &Function,
ASTContext &Context) {
auto Matches = match(declRefExpr(to(functionDecl(equalsNode(&Function))),
unless(hasAncestor(callExpr()))),
Context);
return !Matches.empty();
}

bool hasLoopStmtAncestor(const DeclRefExpr &DeclRef, const Decl &Decl,
ASTContext &Context) {
auto Matches = match(
Expand Down Expand Up @@ -155,12 +146,9 @@ void UnnecessaryValueParamCheck::handleConstRefFix(const FunctionDecl &Function,
// Do not propose fixes when:
// 1. the ParmVarDecl is in a macro, since we cannot place them correctly
// 2. the function is virtual as it might break overrides
// 3. the function is referenced outside of a call expression within the
// compilation unit as the signature change could introduce build errors.
// 4. the function is an explicit template/ specialization.
// 3. the function is an explicit template/ specialization.
const auto *Method = llvm::dyn_cast<CXXMethodDecl>(&Function);
if (Param.getBeginLoc().isMacroID() || (Method && Method->isVirtual()) ||
isReferencedOutsideOfCallExpr(Function, Context) ||
Function.getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
return;
for (const auto *FunctionDecl = &Function; FunctionDecl != nullptr;
Expand Down
5 changes: 5 additions & 0 deletions clang-tools-extra/docs/ReleaseNotes.rst
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Expand Up @@ -110,6 +110,11 @@ Changes in existing checks
<clang-tidy/checks/misc/redundant-expression>` check by providing additional
examples and fixing some macro related false positives.

- Improved :doc:`performance/unnecessary-value-param
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@vbvictor vbvictor Mar 1, 2025

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nit: performance/unnecessary-value-param should be performance-unnecessary-value-param, may be fixed later before 21 release

<clang-tidy/checks/performance/unnecessary-value-param>` check performance by
tolerating fix-it breaking compilation when functions is used as pointers
to avoid matching usage of functions within the current compilation unit.

Removed checks
^^^^^^^^^^^^^^

Expand Down
6 changes: 1 addition & 5 deletions clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-value-param.cpp
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Expand Up @@ -332,11 +332,7 @@ void PositiveNonConstDeclaration(const ExpensiveToCopyType A) {

void PositiveOnlyMessageAsReferencedInCompilationUnit(ExpensiveToCopyType A) {
// CHECK-MESSAGES: [[@LINE-1]]:75: warning: the parameter 'A' is copied
// CHECK-FIXES: void PositiveOnlyMessageAsReferencedInCompilationUnit(ExpensiveToCopyType A) {
}

void ReferenceFunctionOutsideOfCallExpr() {
void (*ptr)(ExpensiveToCopyType) = &PositiveOnlyMessageAsReferencedInCompilationUnit;
// CHECK-FIXES: void PositiveOnlyMessageAsReferencedInCompilationUnit(const ExpensiveToCopyType& A) {
}

void PositiveMessageAndFixAsFunctionIsCalled(ExpensiveToCopyType A) {
Expand Down