[PATCH] Pragma optimize on/off
Dario Domizioli
dario.domizioli at gmail.com
Tue May 6 06:38:20 PDT 2014
Hi,
Please review the attached patch for adding "pragma clang optimize on/off"
to clang.
This pragma is implemented by decorating function definitions in the "off"
regions with attribute 'optnone'.
The syntax and semantics have been discussed in here:
http://lists.cs.uiuc.edu/pipermail/cfe-dev/2014-April/036561.html
The final consensus was that the feature was worth having, and after a
while I think we converged on the syntax, so I am now sending the patch for
review.
Here is a very short summary of how the pragma works:
// The default status is "on".
#pragma clang optimize off
// Function definitions in here are decorated with attribute 'optnone'
// but only if it does not conflict with existing attributes.
#pragma clang optimize on
// Code compiled as normal.
The test provided with the patch checks a number of interesting cases,
including template definitions and instantiations, macros, and conflicting
attributes (e.g. always_inline).
I will prepare another patch for the documentation.
Cheers,
Dario Domizioli
SN Systems - Sony Computer Entertainment Group
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20140506/4f039118/attachment.html>
-------------- next part --------------
Index: lib/Sema/SemaAttr.cpp
===================================================================
--- lib/Sema/SemaAttr.cpp (revision 208078)
+++ lib/Sema/SemaAttr.cpp (working copy)
@@ -470,6 +470,34 @@
D->addAttr(CFAuditedTransferAttr::CreateImplicit(Context, Loc));
}
+void Sema::ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc) {
+ if(On)
+ OptimizeOffPragmaLocation = SourceLocation();
+ else
+ OptimizeOffPragmaLocation = PragmaLoc;
+}
+
+void Sema::AddRangeBasedOptnone(FunctionDecl *FD) {
+ // In the future, check other pragmas if they're implemented (e.g. pragma
+ // optimize 0 will probably map to this functionality too).
+ if(OptimizeOffPragmaLocation.isValid())
+ AddOptnoneAttributeIfNoConflicts(FD, OptimizeOffPragmaLocation);
+}
+
+void Sema::AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD,
+ SourceLocation Loc) {
+ // Don't add a conflicting attribute. No diagnostic is needed.
+ if (FD->hasAttr<MinSizeAttr>() || FD->hasAttr<AlwaysInlineAttr>())
+ return;
+
+ // Add attributes only if required. Optnone requires noinline as well, but if
+ // either is already present then don't bother adding them.
+ if (!FD->hasAttr<OptimizeNoneAttr>())
+ FD->addAttr(OptimizeNoneAttr::CreateImplicit(Context, Loc));
+ if (!FD->hasAttr<NoInlineAttr>())
+ FD->addAttr(NoInlineAttr::CreateImplicit(Context, Loc));
+}
+
typedef std::vector<std::pair<unsigned, SourceLocation> > VisStack;
enum : unsigned { NoVisibility = ~0U };
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp (revision 208078)
+++ lib/Sema/SemaDecl.cpp (working copy)
@@ -7378,6 +7378,11 @@
// marking the function.
AddCFAuditedAttribute(NewFD);
+ // If this is a function definition, check if we have to apply optnone due to
+ // a pragma.
+ if(D.isFunctionDefinition())
+ AddRangeBasedOptnone(NewFD);
+
// If this is the first declaration of an extern C variable, update
// the map of such variables.
if (NewFD->isFirstDecl() && !NewFD->isInvalidDecl() &&
Index: lib/Parse/ParsePragma.cpp
===================================================================
--- lib/Parse/ParsePragma.cpp (revision 208078)
+++ lib/Parse/ParsePragma.cpp (working copy)
@@ -131,6 +131,16 @@
Token &FirstToken) override;
};
+/// PragmaOptimizeHandler - "\#pragma clang optimize on/off".
+struct PragmaOptimizeHandler : public PragmaHandler {
+ PragmaOptimizeHandler(Sema &S)
+ : PragmaHandler("optimize"), Actions(S) {}
+ void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+ Token &FirstToken) override;
+private:
+ Sema &Actions;
+};
+
} // end namespace
void Parser::initializePragmaHandlers() {
@@ -195,6 +205,9 @@
MSSection.reset(new PragmaMSPragma("section"));
PP.AddPragmaHandler(MSSection.get());
}
+
+ OptimizeHandler.reset(new PragmaOptimizeHandler(Actions));
+ PP.AddPragmaHandler("clang", OptimizeHandler.get());
}
void Parser::resetPragmaHandlers() {
@@ -249,6 +262,9 @@
PP.RemovePragmaHandler("STDC", FPContractHandler.get());
FPContractHandler.reset();
+
+ PP.RemovePragmaHandler("clang", OptimizeHandler.get());
+ OptimizeHandler.reset();
}
/// \brief Handle the annotation token produced for #pragma unused(...)
@@ -1531,3 +1547,36 @@
Actions.ActOnPragmaMSComment(Kind, ArgumentString);
}
+
+// #pragma clang optimize off
+// #pragma clang optimize on
+void PragmaOptimizeHandler::HandlePragma(Preprocessor &PP,
+ PragmaIntroducerKind Introducer,
+ Token &FirstToken) {
+ bool isOn = false;
+ Token Tok;
+ PP.Lex(Tok);
+ if (Tok.isNot(tok::identifier)) {
+ PP.Diag(Tok.getLocation(), diag::err_pragma_optimize_malformed);
+ return;
+ }
+ const IdentifierInfo *II = Tok.getIdentifierInfo();
+ if (II->isStr("on")) {
+ isOn = true;
+ PP.Lex(Tok);
+ }
+ else if (II->isStr("off"))
+ PP.Lex(Tok);
+ else {
+ PP.Diag(Tok.getLocation(), diag::err_pragma_optimize_malformed);
+ return;
+ }
+
+ if (Tok.isNot(tok::eod)) {
+ PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol)
+ << "clang optimize";
+ return;
+ }
+
+ Actions.ActOnPragmaOptimize(isOn, FirstToken.getLocation());
+}
Index: test/SemaCXX/pragma-optimize.cpp
===================================================================
--- test/SemaCXX/pragma-optimize.cpp (revision 0)
+++ test/SemaCXX/pragma-optimize.cpp (revision 0)
@@ -0,0 +1,120 @@
+// RUN: %clang_cc1 -x c++ -std=c++11 -emit-llvm -O2 < %s | FileCheck %s
+
+#pragma clang optimize off
+
+#pragma clang optimize on
+
+#pragma clang optimize on top of spaghetti // expected-warning {{extra tokens at end of '#pragma clang optimize' - ignored}}
+
+
+#pragma clang optimize off
+
+// This is a macro definition and therefore its text is not present after
+// preprocessing. The pragma has no effect here.
+#define CREATE_FUNC(name) \
+int name (int param) { \
+ return param; \
+} \
+
+// This is a declaration and therefore it is not decorated with `optnone`.
+extern int foo(int a, int b);
+// CHECK-DAG: @_Z3fooii{{.*}} [[ATTRFOO:#[0-9]+]]
+
+// This is a definition and therefore it will be decorated with `optnone`.
+int bar(int x, int y) {
+ for(int i = 0; i < x; ++i)
+ y += x;
+ return y + foo(x, y);
+}
+// CHECK-DAG: @_Z3barii{{.*}} [[ATTRBAR:#[0-9]+]]
+
+// The function "int created (int param)" created by the macro invocation
+// is also decorated with the `optnone` attribute because it is within a
+// region of code affected by the functionality (not because of the position
+// of the macro definition).
+CREATE_FUNC (created)
+// CHECK-DAG: @_Z7createdi{{.*}} [[ATTRCREATED:#[0-9]+]]
+
+class MyClass {
+ public:
+ // The declaration of the method is not decorated with `optnone`.
+ int method(int blah);
+};
+
+// The definition of the method instead is decorated with `optnone`.
+int MyClass::method(int blah) {
+ return blah + 1;
+}
+// CHECK-DAG: @_ZN7MyClass6methodEi{{.*}} [[ATTRMETHOD:#[0-9]+]]
+
+// A template declaration will not be decorated with `optnone`.
+template <typename T> T twice (T param);
+
+// The template definition will be decorated with the attribute `optnone`.
+template <typename T> T thrice (T param) {
+ return 3 * param;
+}
+
+// This function definition will not be decorated with `optnone` because the
+// attribute would conflict with `always_inline`.
+int __attribute__((always_inline)) baz(int z) {
+ return foo(z, 2);
+}
+// CHECK-DAG: @_Z3bazi{{.*}} [[ATTRBAZ:#[0-9]+]]
+
+#pragma clang optimize on
+
+// The function "int wombat(int param)" created by the macro is not
+// decorated with `optnone`, because the pragma applies its effects only
+// after preprocessing. The position of the macro definition is not
+// relevant.
+CREATE_FUNC (wombat)
+// CHECK-DAG: @_Z6wombati{{.*}} [[ATTRWOMBAT:#[0-9]+]]
+
+// This instantiation of the "twice" template function with a "float" type
+// will not have an `optnone` attribute because the template declaration was
+// not affected by the pragma.
+float container (float par) {
+ return twice(par);
+}
+// CHECK-DAG: @_Z9containerf{{.*}} [[ATTRCONTAINER:#[0-9]+]]
+// CHECK-DAG: @_Z5twiceIfET_S0_{{.*}} [[ATTRTWICE:#[0-9]+]]
+
+// This instantiation of the "thrice" template function with a "float" type
+// will have an `optnone` attribute because the template definition was
+// affected by the pragma.
+float container2 (float par) {
+ return thrice(par);
+}
+// CHECK-DAG: @_Z10container2f{{.*}} [[ATTRCONTAINER2:#[0-9]+]]
+// CHECK-DAG: @_Z6thriceIfET_S0_{{.*}} [[ATTRTHRICEFLOAT:#[0-9]+]]
+
+
+// A template specialization is a new definition and it will not be
+// decorated with an `optnone` attribute because it is now outside of the
+// affected region.
+template<> int thrice(int par) {
+ return (par << 1) + par;
+}
+int container3 (int par) {
+ return thrice(par);
+}
+// CHECK-DAG: @_Z10container3i{{.*}} [[ATTRCONTAINER3:#[0-9]+]]
+// CHECK-DAG: @_Z6thriceIiET_S0_{{.*}} [[ATTRTHRICEINT:#[0-9]+]]
+
+
+// Check for both noinline and optnone on each function that should have them.
+// CHECK-DAG: attributes [[ATTRBAR]] = { {{.*}}noinline{{.*}}optnone{{.*}} }
+// CHECK-DAG: attributes [[ATTRCREATED]] = { {{.*}}noinline{{.*}}optnone{{.*}} }
+// CHECK-DAG: attributes [[ATTRMETHOD]] = { {{.*}}noinline{{.*}}optnone{{.*}} }
+// CHECK-DAG: attributes [[ATTRTHRICEFLOAT]] = { {{.*}}noinline{{.*}}optnone{{.*}} }
+
+// Check that the other functions do NOT have optnone.
+// CHECK-DAG-NOT: attributes [[ATTRFOO]] = { {{.*}}optnone{{.*}} }
+// CHECK-DAG-NOT: attributes [[ATTRBAZ]] = { {{.*}}optnone{{.*}} }
+// CHECK-DAG-NOT: attributes [[ATTRWOMBAT]] = { {{.*}}optnone{{.*}} }
+// CHECK-DAG-NOT: attributes [[ATTRCONTAINER]] = { {{.*}}optnone{{.*}} }
+// CHECK-DAG-NOT: attributes [[ATTRTWICE]] = { {{.*}}optnone{{.*}} }
+// CHECK-DAG-NOT: attributes [[ATTRCONTAINER2]] = { {{.*}}optnone{{.*}} }
+// CHECK-DAG-NOT: attributes [[ATTRCONTAINER3]] = { {{.*}}optnone{{.*}} }
+// CHECK-DAG-NOT: attributes [[ATTRTHRICEINT]] = { {{.*}}optnone{{.*}} }
Index: include/clang/Parse/Parser.h
===================================================================
--- include/clang/Parse/Parser.h (revision 208078)
+++ include/clang/Parse/Parser.h (working copy)
@@ -160,6 +160,7 @@
std::unique_ptr<PragmaHandler> MSConstSeg;
std::unique_ptr<PragmaHandler> MSCodeSeg;
std::unique_ptr<PragmaHandler> MSSection;
+ std::unique_ptr<PragmaHandler> OptimizeHandler;
std::unique_ptr<CommentHandler> CommentSemaHandler;
Index: include/clang/Basic/DiagnosticParseKinds.td
===================================================================
--- include/clang/Basic/DiagnosticParseKinds.td (revision 208078)
+++ include/clang/Basic/DiagnosticParseKinds.td (working copy)
@@ -841,6 +841,9 @@
def err_pragma_pointers_to_members_unknown_kind : Error<
"unexpected %0, expected to see one of %select{|'best_case', 'full_generality', }1"
"'single_inheritance', 'multiple_inheritance', or 'virtual_inheritance'">;
+// - #pragma clang optimize on/off
+def err_pragma_optimize_malformed : Error<
+ "malformed argument to '#pragma clang optimize' - expected 'on' or 'off'">;
// OpenCL Section 6.8.g
def err_not_opencl_storage_class_specifier : Error<
Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h (revision 208078)
+++ include/clang/Sema/Sema.h (working copy)
@@ -333,6 +333,12 @@
/// VisContext - Manages the stack for \#pragma GCC visibility.
void *VisContext; // Really a "PragmaVisStack*"
+ /// OptimizeOffPragmaLocation - it represents the last location of a "#pragma
+ /// clang optimize off" directive if such directive has not been closed by an
+ /// "on" yet. If optimizations are currently "on", this is set to an invalid
+ /// location.
+ SourceLocation OptimizeOffPragmaLocation;
+
/// \brief Flag indicating if Sema is building a recovery call expression.
///
/// This flag is used to avoid building recovery call expressions
@@ -7227,6 +7233,20 @@
/// the appropriate attribute.
void AddCFAuditedAttribute(Decl *D);
+ /// ActOnPragmaOptimize - called on well formed \#pragma clang optimize.
+ void ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc);
+
+ /// Only called on function definitions; if there is a pragma in scope with
+ /// the effect of a range-based optnone, consider marking the function with
+ /// attribute optnone.
+ void AddRangeBasedOptnone(FunctionDecl *FD);
+
+ /// AddOptnoneAttributeIfNoConflicts - adds the 'optnone' attribute to the
+ /// function declaration if there are no conflicts; Loc represents the
+ /// location causing the 'optnone' attribute to be added (usually because of
+ /// a pragma).
+ void AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD, SourceLocation Loc);
+
/// AddAlignedAttr - Adds an aligned attribute to a particular declaration.
void AddAlignedAttr(SourceRange AttrRange, Decl *D, Expr *E,
unsigned SpellingListIndex, bool IsPackExpansion);
More information about the cfe-commits
mailing list