Introduce option -Wargument-larger-than[=N] which warns about function definitions if they take by-value
or return by-value any POD that is larger than some threshold (default is 64 bytes).
Implements rdar://8548050.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@119583 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index aa1b439..d9e3760 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1199,6 +1199,15 @@
CmdArgs.push_back(A->getValue(Args));
}
+ if (Arg *A = Args.getLastArg(options::OPT_Wargument_larger_than_EQ,
+ options::OPT_Wargument_larger_than_def)) {
+ CmdArgs.push_back("-Wargument-larger-than");
+ if (A->getNumValues())
+ CmdArgs.push_back(A->getValue(Args));
+ else
+ CmdArgs.push_back("64"); // default value for -Wargument-larger-than
+ }
+
if (Args.hasArg(options::OPT__relocatable_pch))
CmdArgs.push_back("-relocatable-pch");
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index b20520b..466dfbd 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1373,6 +1373,8 @@
Opts.MathErrno = Args.hasArg(OPT_fmath_errno);
Opts.InstantiationDepth = Args.getLastArgIntValue(OPT_ftemplate_depth, 1024,
Diags);
+ Opts.ArgumentLargerThan = Args.getLastArgIntValue(OPT_Wargument_larger_than,
+ 0, Diags);
Opts.NeXTRuntime = !Args.hasArg(OPT_fgnu_runtime);
Opts.ObjCConstantStringClass =
Args.getLastArgValue(OPT_fconstant_string_class);
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index c246cad..dc017d2 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -26,6 +26,7 @@
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/StmtCXX.h"
+#include "clang/AST/CharUnits.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Parse/ParseDiagnostic.h"
@@ -4864,6 +4865,36 @@
}
}
+void Sema::DiagnoseSizeOfParametersAndReturnValue(ParmVarDecl * const *Param,
+ ParmVarDecl * const *ParamEnd,
+ QualType ReturnTy,
+ NamedDecl *D) {
+ if (LangOpts.ArgumentLargerThan == 0) // No check.
+ return;
+
+ if (ReturnTy->isPODType() &&
+ Diags.getDiagnosticLevel(diag::warn_return_value_size) !=
+ Diagnostic::Ignored) {
+ unsigned Size = Context.getTypeSizeInChars(ReturnTy).getQuantity();
+ if (Size > LangOpts.ArgumentLargerThan)
+ Diag(D->getLocation(), diag::warn_return_value_size)
+ << D->getDeclName() << Size;
+ }
+
+ if (Diags.getDiagnosticLevel(diag::warn_parameter_size)==Diagnostic::Ignored)
+ return;
+
+ for (; Param != ParamEnd; ++Param) {
+ QualType T = (*Param)->getType();
+ if (!T->isPODType())
+ continue;
+ unsigned Size = Context.getTypeSizeInChars(T).getQuantity();
+ if (Size > LangOpts.ArgumentLargerThan)
+ Diag((*Param)->getLocation(), diag::warn_parameter_size)
+ << (*Param)->getDeclName() << Size;
+ }
+}
+
ParmVarDecl *Sema::CheckParameter(DeclContext *DC,
TypeSourceInfo *TSInfo, QualType T,
IdentifierInfo *Name,
@@ -5162,6 +5193,8 @@
if (!FD->isInvalidDecl()) {
DiagnoseUnusedParameters(FD->param_begin(), FD->param_end());
+ DiagnoseSizeOfParametersAndReturnValue(FD->param_begin(), FD->param_end(),
+ FD->getResultType(), FD);
// If this is a constructor, we need a vtable.
if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(FD))
@@ -5175,8 +5208,11 @@
assert(MD == getCurMethodDecl() && "Method parsing confused");
MD->setBody(Body);
MD->setEndLoc(Body->getLocEnd());
- if (!MD->isInvalidDecl())
+ if (!MD->isInvalidDecl()) {
DiagnoseUnusedParameters(MD->param_begin(), MD->param_end());
+ DiagnoseSizeOfParametersAndReturnValue(MD->param_begin(), MD->param_end(),
+ MD->getResultType(), MD);
+ }
} else {
return 0;
}