zbrid created this revision.
Herald added a reviewer: aaron.ballman.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
zbrid requested review of this revision.
Starting with if support first
- Parse attribute check for diagnosable issues with its usage
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D86034
Files:
clang/include/clang/Basic/Attr.td
clang/include/clang/Basic/AttrDocs.td
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaStmtAttr.cpp
clang/test/SemaCXX/attr-harden-misspeculation-unsupported-target.cpp
clang/test/SemaCXX/attr-harden-misspeculation.cpp
Index: clang/test/SemaCXX/attr-harden-misspeculation.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/attr-harden-misspeculation.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only %s -verify
+
+int b(int a, int b) {
+ if (a < b)
+ [[clang::harden_misspeculation]] { // expected-error {{'harden_misspeculation' attribute takes at least 1 argument}}
+ a += 2;
+ }
+
+ if (a == b)
+ [[clang::harden_misspeculation(1)]] { // expected-error {{'harden_misspeculation' attribute requires an identifier}}
+ a += 1;
+ }
+
+ if (a > b)
+ [[clang::harden_misspeculation(a)]] // expected-error {{'harden_misspeculation' attribute is only allowed on compound statements (ie block statements)}}
+ return a;
+
+ return a;
+}
Index: clang/test/SemaCXX/attr-harden-misspeculation-unsupported-target.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/attr-harden-misspeculation-unsupported-target.cpp
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -std=c++11 -triple armv7 -fsyntax-only %s -verify
+
+int b(int a, int b) {
+ if (a < b)
+ [[clang::harden_misspeculation(a)]] { // expected-error {{'harden_misspeculation' attribute is not supported for this target}}
+ return a;
+ }
+ return b;
+}
Index: clang/lib/Sema/SemaStmtAttr.cpp
===================================================================
--- clang/lib/Sema/SemaStmtAttr.cpp
+++ clang/lib/Sema/SemaStmtAttr.cpp
@@ -10,14 +10,16 @@
//
//===----------------------------------------------------------------------===//
-#include "clang/AST/EvaluatedExprVisitor.h"
-#include "clang/Sema/SemaInternal.h"
#include "clang/AST/ASTContext.h"
+#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/TargetInfo.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ScopeInfo.h"
+#include "clang/Sema/SemaInternal.h"
#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Triple.h"
using namespace clang;
using namespace sema;
@@ -51,6 +53,38 @@
return ::new (S.Context) FallThroughAttr(S.Context, A);
}
+static Attr *handleHardenMisspeculationAttr(Sema &S, Stmt *St,
+ const ParsedAttr &A,
+ SourceRange Range) {
+ if (!isa<CompoundStmt>(St)) {
+ S.Diag(A.getRange().getBegin(),
+ diag::err_harden_misspeculation_attr_wrong_target)
+ << A << St->getBeginLoc();
+ }
+
+ // FIXME: Support non-x86_64 targets
+ if (!(S.Context.getTargetInfo().getTriple().getArch() ==
+ llvm::Triple::ArchType::x86_64)) {
+ S.Diag(A.getLoc(), diag::err_attribute_unsupported) << A;
+ return nullptr;
+ }
+
+ if (A.getNumArgs() < 1) {
+ S.Diag(A.getLoc(), diag::err_attribute_too_few_arguments) << A << 1;
+ return nullptr;
+ }
+
+ for (unsigned I = 0, E = A.getNumArgs(); I != E; ++I) {
+ if (!A.isArgIdent(I)) {
+ S.Diag(A.getLoc(), diag::err_attribute_argument_type)
+ << A << AANT_ArgumentIdentifier;
+ return nullptr;
+ }
+ }
+
+ return ::new (S.Context) HardenMisspeculationAttr(S.Context, A);
+}
+
static Attr *handleSuppressAttr(Sema &S, Stmt *St, const ParsedAttr &A,
SourceRange Range) {
if (A.getNumArgs() < 1) {
@@ -374,6 +408,8 @@
return handleOpenCLUnrollHint(S, St, A, Range);
case ParsedAttr::AT_Suppress:
return handleSuppressAttr(S, St, A, Range);
+ case ParsedAttr::AT_HardenMisspeculation:
+ return handleHardenMisspeculationAttr(S, St, A, Range);
case ParsedAttr::AT_NoMerge:
return handleNoMergeAttr(S, St, A, Range);
default:
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9155,6 +9155,10 @@
"fallthrough annotation in unreachable code">,
InGroup<ImplicitFallthrough>, DefaultIgnore;
+def err_harden_misspeculation_attr_wrong_target
+ : Error<"%0 attribute is only allowed on compound statements (ie block "
+ "statements)">;
+
def warn_unreachable_default : Warning<
"default label in switch which covers all enumeration values">,
InGroup<CoveredSwitchDefault>, DefaultIgnore;
Index: clang/include/clang/Basic/AttrDocs.td
===================================================================
--- clang/include/clang/Basic/AttrDocs.td
+++ clang/include/clang/Basic/AttrDocs.td
@@ -3873,6 +3873,13 @@
}];
}
+def HardenMisspeculationDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+TODO(zbrid): Add documentation
+ }];
+}
+
def AbiTagsDocs : Documentation {
let Category = DocCatFunction;
let Content = [{
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -2216,6 +2216,12 @@
let Documentation = [SuppressDocs];
}
+def HardenMisspeculation : StmtAttr {
+ let Spellings = [Clang<"harden_misspeculation">];
+ let Args = [VariadicIdentifierArgument<"VariablesToHarden">];
+ let Documentation = [HardenMisspeculationDocs];
+}
+
def SysVABI : DeclOrTypeAttr {
let Spellings = [GCC<"sysv_abi">];
// let Subjects = [Function, ObjCMethod];
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