-Rename -Wargument-larger-than -> -Wlarge-by-value-copy
-Improve the diagnostic message
-Add some comments
Suggestions by Chris.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@119594 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index 1010e84..711380f 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -158,7 +158,7 @@
def VolatileRegisterVar : DiagGroup<"volatile-register-var">;
def : DiagGroup<"write-strings">;
def CharSubscript : DiagGroup<"char-subscripts">;
-def ArgumentSizeLargerThan : DiagGroup<"argument-larger-than">;
+def LargeByValueCopy : DiagGroup<"large-by-value-copy">;
// Aggregation warning settings.
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index f2cd0ce..198f0e1 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -113,10 +113,12 @@
def warn_used_but_marked_unused: Warning<"%0 was marked unused but was used">,
InGroup<UsedButMarkedUnused>, DefaultIgnore;
-def warn_parameter_size: Warning<"size of %0 is %1 bytes">,
- InGroup<ArgumentSizeLargerThan>;
-def warn_return_value_size: Warning<"return value of %0 is %1 bytes">,
- InGroup<ArgumentSizeLargerThan>;
+def warn_parameter_size: Warning<
+ "%0 is a large (%1 bytes) pass-by-value argument; "
+ "pass it by reference instead ?">, InGroup<LargeByValueCopy>;
+def warn_return_value_size: Warning<
+ "return value of %0 is a large (%1 bytes) pass-by-value object; "
+ "pass it by reference instead ?">, InGroup<LargeByValueCopy>;
def warn_implicit_function_decl : Warning<
"implicit declaration of function %0">,
diff --git a/include/clang/Basic/LangOptions.h b/include/clang/Basic/LangOptions.h
index 558d6dc..2fef7ba 100644
--- a/include/clang/Basic/LangOptions.h
+++ b/include/clang/Basic/LangOptions.h
@@ -122,7 +122,7 @@
public:
unsigned InstantiationDepth; // Maximum template instantiation depth.
- unsigned ArgumentLargerThan; // Warn if parameter/return value is larger
+ unsigned NumLargeByValueCopy; // Warn if parameter/return value is larger
// in bytes than this setting. 0 is no check.
// Version of Microsoft Visual C/C++ we are pretending to be. This is
@@ -177,7 +177,7 @@
InstantiationDepth = 1024;
- ArgumentLargerThan = 0;
+ NumLargeByValueCopy = 0;
Optimize = 0;
OptimizeSize = 0;
diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td
index 78f79c1..87a7680 100644
--- a/include/clang/Driver/CC1Options.td
+++ b/include/clang/Driver/CC1Options.td
@@ -500,11 +500,11 @@
HelpText<"Give inline C++ member functions default visibility by default">;
def ftemplate_depth : Separate<"-ftemplate-depth">,
HelpText<"Maximum depth of recursive template instantiation">;
-def Wargument_larger_than : Separate<"-Wargument-larger-than">,
+def Wlarge_by_value_copy : Separate<"-Wlarge-by-value-copy">,
HelpText<"Warn if a function definition returns or accepts an object larger "
"in bytes that a given value">;
-def Wargument_larger_than_EQ : Joined<"-Wargument-larger-than=">,
- Alias<Wargument_larger_than>;
+def Wlarge_by_value_copy_EQ : Joined<"-Wlarge-by-value-copy=">,
+ Alias<Wlarge_by_value_copy>;
def trigraphs : Flag<"-trigraphs">,
HelpText<"Process trigraph sequences">;
def fwritable_strings : Flag<"-fwritable-strings">,
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 51c3665..0198f34 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -401,8 +401,8 @@
def ftemplate_depth_ : Joined<"-ftemplate-depth-">, Group<f_Group>;
def ftemplate_backtrace_limit_EQ : Joined<"-ftemplate-backtrace-limit=">,
Group<f_Group>;
-def Wargument_larger_than_def : Flag<"-Wargument-larger-than">;
-def Wargument_larger_than_EQ : Joined<"-Wargument-larger-than=">;
+def Wlarge_by_value_copy_def : Flag<"-Wlarge-by-value-copy">;
+def Wlarge_by_value_copy_EQ : Joined<"-Wlarge-by-value-copy=">;
def fterminated_vtables : Flag<"-fterminated-vtables">, Group<f_Group>;
def fthreadsafe_statics : Flag<"-fthreadsafe-statics">, Group<f_Group>;
def ftime_report : Flag<"-ftime-report">, Group<f_Group>;
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index cae11a4..aac36bb 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -760,8 +760,9 @@
void DiagnoseUnusedParameters(ParmVarDecl * const *Begin,
ParmVarDecl * const *End);
- /// \brief Diagnose size of parameters and return value of a Function
- /// or ObjCMethod.
+ /// \brief Diagnose whether the size of parameters or return value of a
+ /// function or obj-c method definition is pass-by-value and larger than a
+ /// specified threshold.
void DiagnoseSizeOfParametersAndReturnValue(ParmVarDecl * const *Begin,
ParmVarDecl * const *End,
QualType ReturnTy,
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index d9e3760..60d2fe3 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1199,13 +1199,13 @@
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 (Arg *A = Args.getLastArg(options::OPT_Wlarge_by_value_copy_EQ,
+ options::OPT_Wlarge_by_value_copy_def)) {
+ CmdArgs.push_back("-Wlarge-by-value-copy");
if (A->getNumValues())
CmdArgs.push_back(A->getValue(Args));
else
- CmdArgs.push_back("64"); // default value for -Wargument-larger-than
+ CmdArgs.push_back("64"); // default value for -Wlarge-by-value-copy.
}
if (Args.hasArg(options::OPT__relocatable_pch))
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 466dfbd..b1d6adb 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1373,7 +1373,7 @@
Opts.MathErrno = Args.hasArg(OPT_fmath_errno);
Opts.InstantiationDepth = Args.getLastArgIntValue(OPT_ftemplate_depth, 1024,
Diags);
- Opts.ArgumentLargerThan = Args.getLastArgIntValue(OPT_Wargument_larger_than,
+ Opts.NumLargeByValueCopy = Args.getLastArgIntValue(OPT_Wlarge_by_value_copy,
0, Diags);
Opts.NeXTRuntime = !Args.hasArg(OPT_fgnu_runtime);
Opts.ObjCConstantStringClass =
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index dc017d2..d36bd17 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -4869,14 +4869,16 @@
ParmVarDecl * const *ParamEnd,
QualType ReturnTy,
NamedDecl *D) {
- if (LangOpts.ArgumentLargerThan == 0) // No check.
+ if (LangOpts.NumLargeByValueCopy == 0) // No check.
return;
+ // Warn if the return value is pass-by-value and larger than the specified
+ // threshold.
if (ReturnTy->isPODType() &&
Diags.getDiagnosticLevel(diag::warn_return_value_size) !=
Diagnostic::Ignored) {
unsigned Size = Context.getTypeSizeInChars(ReturnTy).getQuantity();
- if (Size > LangOpts.ArgumentLargerThan)
+ if (Size > LangOpts.NumLargeByValueCopy)
Diag(D->getLocation(), diag::warn_return_value_size)
<< D->getDeclName() << Size;
}
@@ -4884,12 +4886,14 @@
if (Diags.getDiagnosticLevel(diag::warn_parameter_size)==Diagnostic::Ignored)
return;
+ // Warn if any parameter is pass-by-value and larger than the specified
+ // threshold.
for (; Param != ParamEnd; ++Param) {
QualType T = (*Param)->getType();
if (!T->isPODType())
continue;
unsigned Size = Context.getTypeSizeInChars(T).getQuantity();
- if (Size > LangOpts.ArgumentLargerThan)
+ if (Size > LangOpts.NumLargeByValueCopy)
Diag((*Param)->getLocation(), diag::warn_parameter_size)
<< (*Param)->getDeclName() << Size;
}
diff --git a/test/SemaCXX/warn-argument-larger-than.cpp b/test/SemaCXX/warn-large-by-value-copy.cpp
similarity index 60%
rename from test/SemaCXX/warn-argument-larger-than.cpp
rename to test/SemaCXX/warn-large-by-value-copy.cpp
index 7a80025..39dbd76 100644
--- a/test/SemaCXX/warn-argument-larger-than.cpp
+++ b/test/SemaCXX/warn-large-by-value-copy.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -verify -fsyntax-only -Wargument-larger-than=100 %s
+// RUN: %clang_cc1 -verify -fsyntax-only -Wlarge-by-value-copy=100 %s
// rdar://8548050
namespace rdar8548050 {
@@ -13,8 +13,8 @@
S100 f100(S100 s) { return s; }
-S101 f101(S101 s) { return s; } // expected-warning {{return value of 'f101' is 101 bytes}} \
- // expected-warning {{size of 's' is 101 bytes}}
+S101 f101(S101 s) { return s; } // expected-warning {{return value of 'f101' is a large (101 bytes) pass-by-value object}} \
+ // expected-warning {{'s' is a large (101 bytes) pass-by-value argument}}
typedef int Arr[200];
void farr(Arr a) { }
@@ -32,7 +32,7 @@
};
template <unsigned size>
-void tf(TS<size> ts) {} // expected-warning {{size of 'ts' is 300 bytes}}
+void tf(TS<size> ts) {} // expected-warning {{ts' is a large (300 bytes) pass-by-value argument}}
void g() {
TS<300> ts;