[clang] [clang][frontend] Add support for attribute plugins for statement attributes (PR #110334)
Eric Astor via cfe-commits
cfe-commits at lists.llvm.org
Thu Oct 10 07:25:22 PDT 2024
https://github.com/ericastor updated https://github.com/llvm/llvm-project/pull/110334
>From 0411b2939e10ca335e84731502126145509bef2d Mon Sep 17 00:00:00 2001
From: Eric Astor <epastor at google.com>
Date: Fri, 27 Sep 2024 22:35:28 +0000
Subject: [PATCH 1/3] [clang][frontend] Add support for attribute plugins for
statement attributes
We already have support for declaration attributes; this is just a matter of extending the plugin infrastructure to cover one more case.
---
clang/docs/ClangPlugins.rst | 17 +++++---
clang/examples/Attribute/Attribute.cpp | 49 ++++++++++++++++++++++
clang/include/clang/Basic/ParsedAttrInfo.h | 10 +++++
clang/lib/Sema/SemaStmtAttr.cpp | 4 ++
clang/test/Frontend/plugin-attribute.cpp | 40 ++++++++++++++----
5 files changed, 108 insertions(+), 12 deletions(-)
diff --git a/clang/docs/ClangPlugins.rst b/clang/docs/ClangPlugins.rst
index 001e66e434efb1..92e41fb5877fe8 100644
--- a/clang/docs/ClangPlugins.rst
+++ b/clang/docs/ClangPlugins.rst
@@ -92,11 +92,6 @@ The members of ``ParsedAttrInfo`` that a plugin attribute must define are:
attribute, each of which consists of an attribute syntax and how the
attribute name is spelled for that syntax. If the syntax allows a scope then
the spelling must be "scope::attr" if a scope is present or "::attr" if not.
- * ``handleDeclAttribute``, which is the function that applies the attribute to
- a declaration. It is responsible for checking that the attribute's arguments
- are valid, and typically applies the attribute by adding an ``Attr`` to the
- ``Decl``. It returns either ``AttributeApplied``, to indicate that the
- attribute was successfully applied, or ``AttributeNotApplied`` if it wasn't.
The members of ``ParsedAttrInfo`` that may need to be defined, depending on the
attribute, are:
@@ -105,6 +100,18 @@ attribute, are:
arguments to the attribute.
* ``diagAppertainsToDecl``, which checks if the attribute has been used on the
right kind of declaration and issues a diagnostic if not.
+ * ``handleDeclAttribute``, which is the function that applies the attribute to
+ a declaration. It is responsible for checking that the attribute's arguments
+ are valid, and typically applies the attribute by adding an ``Attr`` to the
+ ``Decl``. It returns either ``AttributeApplied``, to indicate that the
+ attribute was successfully applied, or ``AttributeNotApplied`` if it wasn't.
+ * ``diagAppertainsToStmt``, which checks if the attribute has been used on the
+ right kind of statement and issues a diagnostic if not.
+ * ``handleStmtAttribute``, which is the function that applies the attribute to
+ a statement. It is responsible for checking that the attribute's arguments
+ are valid, and typically applies the attribute by adding an ``Attr`` to the
+ ``Stmt``. It returns either ``AttributeApplied``, to indicate that the
+ attribute was successfully applied, or ``AttributeNotApplied`` if it wasn't.
* ``diagLangOpts``, which checks if the attribute is permitted for the current
language mode and issues a diagnostic if not.
* ``existsInTarget``, which checks if the attribute is permitted for the given
diff --git a/clang/examples/Attribute/Attribute.cpp b/clang/examples/Attribute/Attribute.cpp
index 9d6cf9ae36c6a6..07dd19321195c8 100644
--- a/clang/examples/Attribute/Attribute.cpp
+++ b/clang/examples/Attribute/Attribute.cpp
@@ -94,6 +94,55 @@ struct ExampleAttrInfo : public ParsedAttrInfo {
}
return AttributeApplied;
}
+
+ bool diagAppertainsToStmt(Sema &S, const ParsedAttr &Attr,
+ const Stmt *St) const override {
+ // This attribute appertains to for loop statements only.
+ if (!isa<ForStmt>(St)) {
+ S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type_str)
+ << Attr << Attr.isRegularKeywordAttribute() << "for loop statements";
+ return false;
+ }
+ return true;
+ }
+
+ AttrHandling handleStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &Attr,
+ class Attr *&Result) const override {
+ // We make some rules here:
+ // 1. Only accept at most 3 arguments here.
+ // 2. The first argument must be a string literal if it exists.
+ if (Attr.getNumArgs() > 3) {
+ unsigned ID = S.getDiagnostics().getCustomDiagID(
+ DiagnosticsEngine::Error,
+ "'example' attribute only accepts at most three arguments");
+ S.Diag(Attr.getLoc(), ID);
+ return AttributeNotApplied;
+ }
+ // If there are arguments, the first argument should be a string literal.
+ if (Attr.getNumArgs() > 0) {
+ auto *Arg0 = Attr.getArgAsExpr(0);
+ StringLiteral *Literal =
+ dyn_cast<StringLiteral>(Arg0->IgnoreParenCasts());
+ if (!Literal) {
+ unsigned ID = S.getDiagnostics().getCustomDiagID(
+ DiagnosticsEngine::Error, "first argument to the 'example' "
+ "attribute must be a string literal");
+ S.Diag(Attr.getLoc(), ID);
+ return AttributeNotApplied;
+ }
+ SmallVector<Expr *, 16> ArgsBuf;
+ for (unsigned i = 0; i < Attr.getNumArgs(); i++) {
+ ArgsBuf.push_back(Attr.getArgAsExpr(i));
+ }
+ Result = AnnotateAttr::Create(S.Context, "example", ArgsBuf.data(),
+ ArgsBuf.size(), Attr.getRange());
+ } else {
+ // Attach an annotate attribute to the Decl.
+ Result = AnnotateAttr::Create(S.Context, "example", nullptr, 0,
+ Attr.getRange());
+ }
+ return AttributeApplied;
+ }
};
} // namespace
diff --git a/clang/include/clang/Basic/ParsedAttrInfo.h b/clang/include/clang/Basic/ParsedAttrInfo.h
index 537d8f3391d589..fab5c6f1377d27 100644
--- a/clang/include/clang/Basic/ParsedAttrInfo.h
+++ b/clang/include/clang/Basic/ParsedAttrInfo.h
@@ -24,6 +24,7 @@
namespace clang {
+class Attr;
class Decl;
class LangOptions;
class ParsedAttr;
@@ -154,6 +155,15 @@ struct ParsedAttrInfo {
const ParsedAttr &Attr) const {
return NotHandled;
}
+ /// If this ParsedAttrInfo knows how to handle this ParsedAttr applied to this
+ /// Stmt then do so (referencing the resulting Attr in Result) and return
+ /// either AttributeApplied if it was applied or AttributeNotApplied if it
+ /// wasn't. Otherwise return NotHandled.
+ virtual AttrHandling handleStmtAttribute(Sema &S, Stmt *St,
+ const ParsedAttr &Attr,
+ class Attr *&Result) const {
+ return NotHandled;
+ }
static const ParsedAttrInfo &get(const AttributeCommonInfo &A);
static ArrayRef<const ParsedAttrInfo *> getAllBuiltin();
diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index b9b3b4063bc383..3ebd1148e8bbfb 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -680,6 +680,10 @@ static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &A,
case ParsedAttr::AT_NoConvergent:
return handleNoConvergentAttr(S, St, A, Range);
default:
+ if (Attr *AT = nullptr; A.getInfo().handleStmtAttribute(S, St, A, AT) !=
+ ParsedAttrInfo::NotHandled) {
+ return AT;
+ }
// N.B., ClangAttrEmitter.cpp emits a diagnostic helper that ensures a
// declaration attribute is not written on a statement, but this code is
// needed for attributes in Attr.td that do not list any subjects.
diff --git a/clang/test/Frontend/plugin-attribute.cpp b/clang/test/Frontend/plugin-attribute.cpp
index 1c5a2440b26888..2e9d171a0095a9 100644
--- a/clang/test/Frontend/plugin-attribute.cpp
+++ b/clang/test/Frontend/plugin-attribute.cpp
@@ -4,11 +4,33 @@
// REQUIRES: plugins, examples
//--- good_attr.cpp
// expected-no-diagnostics
-void fn1a() __attribute__((example)) {}
-[[example]] void fn1b() {}
-[[plugin::example]] void fn1c() {}
-void fn2() __attribute__((example("somestring", 1, 2.0))) {}
-// CHECK-COUNT-4: -AnnotateAttr 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} "example"
+void fn1a() __attribute__((example)) {
+ __attribute__((example)) for (int i = 0; i < 10; ++i) {}
+}
+[[example]] void fn1b() {
+ [[example]] for (int i = 0; i < 10; ++i) {}
+}
+[[plugin::example]] void fn1c() {
+ [[plugin::example]] for (int i = 0; i < 10; ++i) {}
+}
+void fn2() __attribute__((example("somestring", 1, 2.0))) {
+ __attribute__((example("abc", 3, 4.0))) for (int i = 0; i < 10; ++i) {}
+}
+// CHECK: -AttributedStmt 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}}
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} "example"
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}} "example"
+// CHECK: -AttributedStmt 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}}
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} "example"
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}} "example"
+// CHECK: -AttributedStmt 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}}
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} "example"
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}} "example"
+// CHECK: -AttributedStmt 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}}
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} "example"
+// CHECK: -StringLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'const char[{{[0-9]+}}]' lvalue "abc"
+// CHECK: -IntegerLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'int' 3
+// CHECK: -FloatingLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'double' 4.000000e+00
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}} "example"
// CHECK: -StringLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'const char[{{[0-9]+}}]' lvalue "somestring"
// CHECK: -IntegerLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'int' 1
// CHECK: -FloatingLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'double' 2.000000e+00
@@ -18,5 +40,9 @@ int var1 __attribute__((example("otherstring"))) = 1; // expected-warning {{'exa
class Example {
void __attribute__((example)) fn3(); // expected-error {{'example' attribute only allowed at file scope}}
};
-void fn4() __attribute__((example(123))) { } // expected-error {{first argument to the 'example' attribute must be a string literal}}
-void fn5() __attribute__((example("a","b", 3, 4.0))) { } // expected-error {{'example' attribute only accepts at most three arguments}}
+void fn4() __attribute__((example(123))) { // expected-error {{first argument to the 'example' attribute must be a string literal}}
+ __attribute__((example("somestring"))) while (true); // expected-warning {{'example' attribute only applies to for loop statements}}
+}
+void fn5() __attribute__((example("a","b", 3, 4.0))) { // expected-error {{'example' attribute only accepts at most three arguments}}
+ __attribute__((example("a","b", 3, 4.0))) for (int i = 0; i < 10; ++i) {} // expected-error {{'example' attribute only accepts at most three arguments}}
+}
>From 2398a73022d1f6d2d669e2265e8cdb7a5e3425a9 Mon Sep 17 00:00:00 2001
From: Eric Astor <epastor at google.com>
Date: Mon, 30 Sep 2024 13:20:23 +0000
Subject: [PATCH 2/3] Fix desync'd comment
---
clang/examples/Attribute/Attribute.cpp | 1 -
1 file changed, 1 deletion(-)
diff --git a/clang/examples/Attribute/Attribute.cpp b/clang/examples/Attribute/Attribute.cpp
index 07dd19321195c8..3b90724ad22205 100644
--- a/clang/examples/Attribute/Attribute.cpp
+++ b/clang/examples/Attribute/Attribute.cpp
@@ -137,7 +137,6 @@ struct ExampleAttrInfo : public ParsedAttrInfo {
Result = AnnotateAttr::Create(S.Context, "example", ArgsBuf.data(),
ArgsBuf.size(), Attr.getRange());
} else {
- // Attach an annotate attribute to the Decl.
Result = AnnotateAttr::Create(S.Context, "example", nullptr, 0,
Attr.getRange());
}
>From 5a5ff132a96c471c079b35851c6c067687dc28e0 Mon Sep 17 00:00:00 2001
From: Eric Astor <epastor at google.com>
Date: Wed, 9 Oct 2024 17:05:13 +0000
Subject: [PATCH 3/3] Add support for template-instantiations of AnnotateAttr
---
clang/lib/Sema/SemaTemplateInstantiate.cpp | 14 ++++++++++++++
clang/test/Frontend/plugin-attribute.cpp | 20 ++++++++++++++++----
2 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index fd51fa4afcacbf..00a5f81dbca8fe 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -1537,6 +1537,7 @@ namespace {
NamedDecl *FirstQualifierInScope = nullptr,
bool AllowInjectedClassName = false);
+ const AnnotateAttr *TransformAnnotateAttr(const AnnotateAttr *AA);
const CXXAssumeAttr *TransformCXXAssumeAttr(const CXXAssumeAttr *AA);
const LoopHintAttr *TransformLoopHintAttr(const LoopHintAttr *LH);
const NoInlineAttr *TransformStmtNoInlineAttr(const Stmt *OrigS,
@@ -2125,6 +2126,19 @@ TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
Arg, PackIndex);
}
+const AnnotateAttr *
+TemplateInstantiator::TransformAnnotateAttr(const AnnotateAttr *AA) {
+ SmallVector<Expr *> Args;
+ for (Expr *Arg : AA->args()) {
+ ExprResult Res = getDerived().TransformExpr(Arg);
+ if (!Res.isUsable())
+ return AA;
+ Args.push_back(Res.get());
+ }
+ return AnnotateAttr::CreateImplicit(getSema().Context, AA->getAnnotation(),
+ Args.data(), Args.size(), AA->getRange());
+}
+
const CXXAssumeAttr *
TemplateInstantiator::TransformCXXAssumeAttr(const CXXAssumeAttr *AA) {
ExprResult Res = getDerived().TransformExpr(AA->getAssumption());
diff --git a/clang/test/Frontend/plugin-attribute.cpp b/clang/test/Frontend/plugin-attribute.cpp
index 2e9d171a0095a9..094ce9f5cbb85f 100644
--- a/clang/test/Frontend/plugin-attribute.cpp
+++ b/clang/test/Frontend/plugin-attribute.cpp
@@ -5,17 +5,21 @@
//--- good_attr.cpp
// expected-no-diagnostics
void fn1a() __attribute__((example)) {
- __attribute__((example)) for (int i = 0; i < 10; ++i) {}
+ __attribute__((example)) for (int i = 0; i < 9; ++i) {}
}
[[example]] void fn1b() {
- [[example]] for (int i = 0; i < 10; ++i) {}
+ [[example]] for (int i = 0; i < 9; ++i) {}
}
[[plugin::example]] void fn1c() {
- [[plugin::example]] for (int i = 0; i < 10; ++i) {}
+ [[plugin::example]] for (int i = 0; i < 9; ++i) {}
}
void fn2() __attribute__((example("somestring", 1, 2.0))) {
- __attribute__((example("abc", 3, 4.0))) for (int i = 0; i < 10; ++i) {}
+ __attribute__((example("abc", 3, 4.0))) for (int i = 0; i < 9; ++i) {}
}
+template <int N> void template_fn() __attribute__((example("template", N))) {
+ __attribute__((example("def", N + 1))) for (int i = 0; i < 9; ++i) {}
+}
+void fn3() { template_fn<5>(); }
// CHECK: -AttributedStmt 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}}
// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} "example"
// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}} "example"
@@ -34,6 +38,14 @@ void fn2() __attribute__((example("somestring", 1, 2.0))) {
// CHECK: -StringLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'const char[{{[0-9]+}}]' lvalue "somestring"
// CHECK: -IntegerLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'int' 1
// CHECK: -FloatingLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'double' 2.000000e+00
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} Implicit "example"
+// CHECK: -StringLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'const char[{{[0-9]+}}]' lvalue "def"
+// CHECK: -BinaryOperator 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'int' '+'
+// CHECK: -IntegerLiteral 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}} 'int' 5
+// CHECK: -IntegerLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'int' 1
+// CHECK: -AnnotateAttr 0x{{[0-9a-z]+}} {{<line:[0-9]+:[0-9]+(, col:[0-9]+)?>}} "example"
+// CHECK: -StringLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'const char[{{[0-9]+}}]' lvalue "template"
+// CHECK: -IntegerLiteral 0x{{[0-9a-z]+}} {{<col:[0-9]+(, col:[0-9]+)?>}} 'int' 5
//--- bad_attr.cpp
int var1 __attribute__((example("otherstring"))) = 1; // expected-warning {{'example' attribute only applies to functions}}
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