acomminos updated this revision to Diff 155246.
acomminos added a comment.
Thanks for the feedback! This diff switches to using a source range for
captures provided by the parser, which is more accurate, future-proof, and
correctly handles macros.
Repository:
rC Clang
https://reviews.llvm.org/D48845
Files:
include/clang/Sema/DeclSpec.h
include/clang/Sema/ScopeInfo.h
include/clang/Sema/Sema.h
lib/Parse/ParseExprCXX.cpp
lib/Sema/SemaLambda.cpp
test/FixIt/fixit-unused-lambda-capture.cpp
Index: test/FixIt/fixit-unused-lambda-capture.cpp
===================================================================
--- /dev/null
+++ test/FixIt/fixit-unused-lambda-capture.cpp
@@ -0,0 +1,71 @@
+// RUN: cp %s %t
+// RUN: %clang_cc1 -x c++ -fsyntax-only -Wunused-lambda-capture -std=c++1z -fixit %t
+// RUN: grep -v CHECK %t | FileCheck %s
+
+void test() {
+ int i = 0;
+ int j = 0;
+ int k = 0;
+ int c = 10;
+ int a[c];
+
+ [i,j] { return i; };
+ // CHECK: [i] { return i; };
+ [i,j] { return j; };
+ // CHECK: [j] { return j; };
+ [i,j,k] {};
+ // CHECK: [] {};
+ [i,j,k] { return i + j; };
+ // CHECK: [i,j] { return i + j; };
+ [i,j,k] { return j + k; };
+ // CHECK: [j,k] { return j + k; };
+ [i,j,k] { return i + k; };
+ // CHECK: [i,k] { return i + k; };
+ [i,j,k] { return i + j + k; };
+ // CHECK: [i,j,k] { return i + j + k; };
+ [&,i] { return k; };
+ // CHECK: [&] { return k; };
+ [=,&i] { return k; };
+ // CHECK: [=] { return k; };
+ [=,&i,&j] { return j; };
+ // CHECK: [=,&j] { return j; };
+ [=,&i,&j] { return i; };
+ // CHECK: [=,&i] { return i; };
+ [z = i] {};
+ // CHECK: [] {};
+ [i,z = i,j] { return z; };
+ // CHECK: [z = i] { return z; };
+ [&a] {};
+ // CHECK: [] {};
+
+ #define I_MACRO() i
+ #define I_REF_MACRO() &i
+ [I_MACRO()] {};
+ // CHECK: [] {};
+ [I_MACRO(),j] { return j; };
+ // CHECK: [j] { return j; };
+ [j,I_MACRO()] { return j; };
+ // CHECK: [j] { return j; };
+ [I_REF_MACRO(),j] { return j; };
+ // CHECK: [j] { return j; };
+ [j,I_REF_MACRO()] { return j; };
+ // CHECK: [j] { return j; };
+}
+
+class ThisTest {
+ void test() {
+ int i = 0;
+ [this] {};
+ // CHECK: [] {};
+ [i,this] { return i; };
+ // CHECK: [i] { return i; };
+ [this,i] { return i; };
+ // CHECK: [i] { return i; };
+ [*this] {};
+ // CHECK: [] {};
+ [*this,i] { return i; };
+ // CHECK: [i] { return i; };
+ [i,*this] { return i; };
+ // CHECK: [i] { return i; };
+ }
+};
Index: lib/Sema/SemaLambda.cpp
===================================================================
--- lib/Sema/SemaLambda.cpp
+++ lib/Sema/SemaLambda.cpp
@@ -824,6 +824,7 @@
LSI->addCapture(Var, /*isBlock*/false, Var->getType()->isReferenceType(),
/*isNested*/false, Var->getLocation(), SourceLocation(),
Var->getType(), Var->getInit());
+
return Field;
}
@@ -954,6 +955,9 @@
= Intro.Default == LCD_None? Intro.Range.getBegin() : Intro.DefaultLoc;
for (auto C = Intro.Captures.begin(), E = Intro.Captures.end(); C != E;
PrevCaptureLoc = C->Loc, ++C) {
+ LSI->ExplicitCaptureRanges[C - Intro.Captures.begin()] =
+ SourceRange(C->LocStart, C->LocEnd);
+
if (C->Kind == LCK_This || C->Kind == LCK_StarThis) {
if (C->Kind == LCK_StarThis)
Diag(C->Loc, !getLangOpts().CPlusPlus17
@@ -1478,7 +1482,8 @@
return false;
}
-void Sema::DiagnoseUnusedLambdaCapture(const Capture &From) {
+void Sema::DiagnoseUnusedLambdaCapture(const SourceRange CaptureRange,
+ const Capture &From) {
if (CaptureHasSideEffects(From))
return;
@@ -1491,6 +1496,7 @@
else
diag << From.getVariable();
diag << From.isNonODRUsed();
+ diag << FixItHint::CreateRemoval(CaptureRange);
}
ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
@@ -1532,19 +1538,47 @@
// Translate captures.
auto CurField = Class->field_begin();
+ // True if the current capture has a used capture or default before it.
+ bool CurHasPreviousCapture = CaptureDefault != LCD_None;
+ SourceLocation PrevCaptureLoc = CurHasPreviousCapture ?
+ CaptureDefaultLoc : IntroducerRange.getBegin();
+
for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I, ++CurField) {
const Capture &From = LSI->Captures[I];
assert(!From.isBlockCapture() && "Cannot capture __block variables");
bool IsImplicit = I >= LSI->NumExplicitCaptures;
+ // Use source ranges of explicit captures for fixits where available.
+ SourceRange CaptureRange = LSI->ExplicitCaptureRanges[I];
+ if (CaptureRange.isInvalid()) {
+ CaptureRange = SourceRange(From.getLocation());
+ }
+
// Warn about unused explicit captures.
+ bool IsCaptureUsed = true;
if (!CurContext->isDependentContext() && !IsImplicit && !From.isODRUsed()) {
// Initialized captures that are non-ODR used may not be eliminated.
bool NonODRUsedInitCapture =
IsGenericLambda && From.isNonODRUsed() && From.getInitExpr();
- if (!NonODRUsedInitCapture)
- DiagnoseUnusedLambdaCapture(From);
+ if (!NonODRUsedInitCapture) {
+ bool IsLast = (I + 1) == LSI->NumExplicitCaptures;
+ SourceRange FixItRange;
+ if (!CurHasPreviousCapture && !IsLast) {
+ // If there are no captures preceding this capture, remove the
+ // following comma.
+ FixItRange = SourceRange(CaptureRange.getBegin(),
+ getLocForEndOfToken(CaptureRange.getEnd()));
+ } else {
+ // Otherwise, remove the comma since the last used capture.
+ FixItRange = SourceRange(getLocForEndOfToken(PrevCaptureLoc),
+ CaptureRange.getEnd());
+ }
+
+ DiagnoseUnusedLambdaCapture(FixItRange, From);
+ IsCaptureUsed = false;
+ }
}
+ CurHasPreviousCapture |= IsCaptureUsed;
// Handle 'this' capture.
if (From.isThisCapture()) {
@@ -1574,6 +1608,8 @@
Init = InitResult.get();
}
CaptureInits.push_back(Init);
+
+ PrevCaptureLoc = CaptureRange.getEnd();
}
// C++11 [expr.prim.lambda]p6:
Index: lib/Parse/ParseExprCXX.cpp
===================================================================
--- lib/Parse/ParseExprCXX.cpp
+++ lib/Parse/ParseExprCXX.cpp
@@ -808,6 +808,7 @@
IdentifierInfo *Id = nullptr;
SourceLocation EllipsisLoc;
ExprResult Init;
+ SourceLocation LocStart = Tok.getLocation();
if (Tok.is(tok::star)) {
Loc = ConsumeToken();
@@ -981,8 +982,11 @@
Loc, Kind == LCK_ByRef, Id, InitKind, InitExpr);
Init = InitExpr;
}
+
+ SourceLocation LocEnd = PrevTokLocation;
+
Intro.addCapture(Kind, Loc, Id, EllipsisLoc, InitKind, Init,
- InitCaptureType);
+ InitCaptureType, LocStart, LocEnd);
}
T.consumeClose();
Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h
+++ include/clang/Sema/Sema.h
@@ -5604,7 +5604,8 @@
bool CaptureHasSideEffects(const sema::Capture &From);
/// Diagnose if an explicit lambda capture is unused.
- void DiagnoseUnusedLambdaCapture(const sema::Capture &From);
+ void DiagnoseUnusedLambdaCapture(const SourceRange CaptureRange,
+ const sema::Capture &From);
/// Complete a lambda-expression having processed and attached the
/// lambda body.
Index: include/clang/Sema/ScopeInfo.h
===================================================================
--- include/clang/Sema/ScopeInfo.h
+++ include/clang/Sema/ScopeInfo.h
@@ -829,6 +829,9 @@
/// if the enclosing full-expression is instantiation dependent).
llvm::SmallSet<Expr *, 8> NonODRUsedCapturingExprs;
+ /// Contains source ranges for explicit captures within introducers.
+ llvm::DenseMap<unsigned, SourceRange> ExplicitCaptureRanges;
+
/// Contains all of the variables defined in this lambda that shadow variables
/// that were defined in parent contexts. Used to avoid warnings when the
/// shadowed variables are uncaptured by this lambda.
Index: include/clang/Sema/DeclSpec.h
===================================================================
--- include/clang/Sema/DeclSpec.h
+++ include/clang/Sema/DeclSpec.h
@@ -2549,12 +2549,17 @@
LambdaCaptureInitKind InitKind;
ExprResult Init;
ParsedType InitCaptureType;
+ SourceLocation LocStart;
+ SourceLocation LocEnd;
+
LambdaCapture(LambdaCaptureKind Kind, SourceLocation Loc,
IdentifierInfo *Id, SourceLocation EllipsisLoc,
LambdaCaptureInitKind InitKind, ExprResult Init,
- ParsedType InitCaptureType)
+ ParsedType InitCaptureType, SourceLocation LocStart,
+ SourceLocation LocEnd)
: Kind(Kind), Loc(Loc), Id(Id), EllipsisLoc(EllipsisLoc),
- InitKind(InitKind), Init(Init), InitCaptureType(InitCaptureType) {}
+ InitKind(InitKind), Init(Init), InitCaptureType(InitCaptureType),
+ LocStart(LocStart), LocEnd(LocEnd) {}
};
SourceRange Range;
@@ -2572,9 +2577,11 @@
SourceLocation EllipsisLoc,
LambdaCaptureInitKind InitKind,
ExprResult Init,
- ParsedType InitCaptureType) {
+ ParsedType InitCaptureType,
+ SourceLocation LocStart,
+ SourceLocation LocEnd) {
Captures.push_back(LambdaCapture(Kind, Loc, Id, EllipsisLoc, InitKind, Init,
- InitCaptureType));
+ InitCaptureType, LocStart, LocEnd));
}
};
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