jcai19 created this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
When using -ftrivial-auto-var-init=* options to initiate automatic
variables in a file, to disable initialization on some variables,
currently we have to manually annotate the variables with uninitialized
attribute, such as
int dont_initialize_me __attribute((uninitialized));
Making pragma clang attribute to support this attribute would make
annotating variables much easier, and could be particular useful for
bisection efforts, e.g.
void use(void*);
void buggy() {
int arr[256];
int boom;
float bam;
struct { int oops; } oops;
union { int oof; float aaaaa; } oof;
use(&arr);
use(&boom);
use(&bam);
use(&oops);
use(&oof);
}
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D78693
Files:
clang/include/clang/Basic/Attr.td
clang/test/CodeGenCXX/trivial-auto-var-init-attribute.cpp
clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/Parser/pragma-attribute.cpp
Index: clang/test/Parser/pragma-attribute.cpp
===================================================================
--- clang/test/Parser/pragma-attribute.cpp
+++ clang/test/Parser/pragma-attribute.cpp
@@ -63,14 +63,14 @@
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = hasType(functionType)) // OK
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable( )) // expected-error {{expected ')'}}
-#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable( ) )) // expected-error {{expected an identifier that corresponds to an attribute subject matcher sub-rule; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_parameter', 'unless(is_parameter)'}}
-#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable(is ) )) // expected-error {{unknown attribute subject matcher sub-rule 'is'; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_parameter', 'unless(is_parameter)'}}
+#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any(variable())) // expected-error {{expected an identifier that corresponds to an attribute subject matcher sub-rule; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_local', 'is_parameter', 'unless(is_parameter)'}}
+#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any(variable(is))) // expected-error {{unknown attribute subject matcher sub-rule 'is'; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_local', 'is_parameter', 'unless(is_parameter)'}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable(is_parameter, not) )) // expected-error {{expected ')'}} expected-note {{to match this '('}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable is_parameter )) // expected-error {{expected ')'}} expected-note {{to match this '('}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable ( ) // expected-error {{expected ')'}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = variable ( // expected-error {{expected ')'}}
-#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( function, variable (is ()) )) // expected-error {{unknown attribute subject matcher sub-rule 'is'; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_parameter', 'unless(is_parameter)'}}
-#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( function, variable (42) )) // expected-error {{expected an identifier that corresponds to an attribute subject matcher sub-rule; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_parameter', 'unless(is_parameter)'}}
+#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any(function, variable(is()))) // expected-error {{unknown attribute subject matcher sub-rule 'is'; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_local', 'is_parameter', 'unless(is_parameter)'}}
+#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any(function, variable(42))) // expected-error {{expected an identifier that corresponds to an attribute subject matcher sub-rule; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_local', 'is_parameter', 'unless(is_parameter)'}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( function, namespace("test") )) // expected-error {{expected an identifier that corresponds to an attribute subject matcher sub-rule; 'namespace' matcher does not support sub-rules}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( function, variable ("test" )) // expected-error {{expected ')'}}
@@ -79,15 +79,15 @@
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any (function, variable (unless) )) // expected-error {{expected '('}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any (function, variable (unless() )) // expected-error {{expected ')'}}
-#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any ( function, variable (unless(is)) )) // expected-error {{unknown attribute subject matcher sub-rule 'unless(is)'; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_parameter', 'unless(is_parameter)'}}
+#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any(function, variable(unless(is)))) // expected-error {{unknown attribute subject matcher sub-rule 'unless(is)'; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_local', 'is_parameter', 'unless(is_parameter)'}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable(unless(is_parameter, not)) )) // expected-error {{expected ')'}} expected-note {{to match this '('}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable(unless(is_parameter), not) ) // expected-error {{expected ')'}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable unless is_parameter )) // expected-error {{expected ')'}} expected-note {{to match this '('}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( variable(unless is_parameter) )) // expected-error {{expected '('}}
-#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( function, variable (unless(42)) )) // expected-error {{expected an identifier that corresponds to an attribute subject matcher sub-rule; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_parameter', 'unless(is_parameter)'}}
+#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any(function, variable(unless(42)))) // expected-error {{expected an identifier that corresponds to an attribute subject matcher sub-rule; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_local', 'is_parameter', 'unless(is_parameter)'}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( function, enum(unless("test")) )) // expected-error {{expected an identifier that corresponds to an attribute subject matcher sub-rule; 'enum' matcher does not support sub-rules}}
-#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( function, variable (unless(is_global)) )) // expected-error {{unknown attribute subject matcher sub-rule 'unless(is_global)'; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_parameter', 'unless(is_parameter)'}}
+#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any(function, variable(unless(is_global)))) // expected-error {{unknown attribute subject matcher sub-rule 'unless(is_global)'; 'variable' matcher supports the following sub-rules: 'is_thread_local', 'is_global', 'is_local', 'is_parameter', 'unless(is_parameter)'}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( enum(unless(is_parameter)) )) // expected-error {{invalid use of attribute subject matcher sub-rule 'unless(is_parameter)'; 'enum' matcher does not support sub-rules}}
#pragma clang attribute push(__attribute__((annotate("test"))), apply_to = any( function, function )) // expected-error {{duplicate attribute subject matcher 'function'}}
@@ -182,3 +182,16 @@
// expected-note@-1 {{use the GNU '__attribute__' syntax}}
#pragma clang attribute push (annotate("test")) // expected-error {{expected an attribute that is specified using the GNU, C++11 or '__declspec' syntax}}
// expected-note@-1 {{use the GNU '__attribute__' syntax}}
+
+#pragma clang attribute push([[clang::uninitialized]], apply_to = variable(is_local))
+#pragma clang attribute pop
+#pragma clang attribute push([[clang::uninitialized]], apply_to = function) // expected-error {{attribute 'uninitialized' can't be applied to 'function'}}
+#pragma clang attribute pop
+#pragma clang attribute push([[clang::uninitialized]], apply_to = variable) // expected-error {{attribute 'uninitialized' can't be applied to 'variable'}}
+#pragma clang attribute pop
+#pragma clang attribute push([[clang::uninitialized]], apply_to = variable(is_thread_local)) // expected-error {{attribute 'uninitialized' can't be applied to 'variable(is_thread_local)'}}
+#pragma clang attribute pop
+#pragma clang attribute push([[clang::uninitialized]], apply_to = variable(is_global)) // expected-error {{attribute 'uninitialized' can't be applied to 'variable(is_global)'}}
+#pragma clang attribute pop
+#pragma clang attribute push([[clang::uninitialized]], apply_to = any(variable(is_parameter), variable(unless(is_parameter)))) // expected-error {{attribute 'uninitialized' can't be applied to 'variable(is_parameter)', and 'variable(unless(is_parameter))'}}
+#pragma clang attribute pop
Index: clang/test/Misc/pragma-attribute-supported-attributes-list.test
===================================================================
--- clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -41,6 +41,7 @@
// CHECK-NEXT: Callback (SubjectMatchRule_function)
// CHECK-NEXT: Capability (SubjectMatchRule_record, SubjectMatchRule_type_alias)
// CHECK-NEXT: CarriesDependency (SubjectMatchRule_variable_is_parameter, SubjectMatchRule_objc_method, SubjectMatchRule_function)
+// CHECK-NEXT: Cleanup (SubjectMatchRule_variable_is_local)
// CHECK-NEXT: CmseNSEntry (SubjectMatchRule_function)
// CHECK-NEXT: Cold (SubjectMatchRule_function)
// CHECK-NEXT: Common (SubjectMatchRule_variable)
@@ -151,6 +152,7 @@
// CHECK-NEXT: Target (SubjectMatchRule_function)
// CHECK-NEXT: TestTypestate (SubjectMatchRule_function_is_member)
// CHECK-NEXT: TrivialABI (SubjectMatchRule_record)
+// CHECK-NEXT: Uninitialized (SubjectMatchRule_variable_is_local)
// CHECK-NEXT: UseHandle (SubjectMatchRule_variable_is_parameter)
// CHECK-NEXT: VecReturn (SubjectMatchRule_record)
// CHECK-NEXT: VecTypeHint (SubjectMatchRule_function)
Index: clang/test/CodeGenCXX/trivial-auto-var-init-attribute.cpp
===================================================================
--- clang/test/CodeGenCXX/trivial-auto-var-init-attribute.cpp
+++ clang/test/CodeGenCXX/trivial-auto-var-init-attribute.cpp
@@ -20,4 +20,35 @@
used(i);
}
+#pragma clang attribute push([[clang::uninitialized]], apply_to = variable(is_local))
+// UNINIT-LABEL: test_pragma_attribute_uninitialized_f1(
+// UNINIT: alloca
+// UNINIT-NEXT: call void
+// ZERO-LABEL: test_pragma_attribute_uninitialized_f1(
+// ZERO: alloca
+// ZERO-NEXT: call void
+// PATTERN-LABEL: test_pragma_attribute_uninitialized_f1(
+// PATTERN: alloca
+// PATTERN-NEXT: call void
+void test_pragma_attribute_uninitialized_f1() {
+ int i;
+ used(i);
+}
+
+// UNINIT-LABEL: test_pragma_attribute_uninitialized_f2(
+// UNINIT: alloca
+// UNINIT-NEXT: call void
+// ZERO-LABEL: test_pragma_attribute_uninitialized_f2(
+// ZERO: alloca
+// ZERO-NEXT: call void
+// PATTERN-LABEL: test_pragma_attribute_uninitialized_f2(
+// PATTERN: alloca
+// PATTERN-NEXT: call void
+void test_pragma_attribute_uninitialized_f2() {
+ int i;
+ used(i);
+}
+
+#pragma clang attribute pop
+
} // extern "C"
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -441,6 +441,7 @@
def SubjectMatcherForVar : AttrSubjectMatcherRule<"variable", [Var], [
AttrSubjectMatcherSubRule<"is_thread_local", [TLSVar]>,
AttrSubjectMatcherSubRule<"is_global", [GlobalVar]>,
+ AttrSubjectMatcherSubRule<"is_local", [LocalVar]>,
AttrSubjectMatcherSubRule<"is_parameter", [ParmVar]>,
// unless(is_parameter)
AttrSubjectMatcherSubRule<"is_parameter", [NonParmVar], 1>
@@ -3381,6 +3382,7 @@
def Uninitialized : InheritableAttr {
let Spellings = [Clang<"uninitialized", 0>];
let Subjects = SubjectList<[LocalVar]>;
+ let PragmaAttributeSupport = 1;
let Documentation = [UninitializedDocs];
}
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