[llvm-branch-commits] [clang] b2ba686 - Refactoring the attribute plugin example to fit the new API

Aaron Ballman via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Mon Dec 21 05:29:04 PST 2020


Author: Yafei Liu
Date: 2020-12-21T08:24:09-05:00
New Revision: b2ba6867eac10874bd279c739639bdb9e60c1996

URL: https://github.com/llvm/llvm-project/commit/b2ba6867eac10874bd279c739639bdb9e60c1996
DIFF: https://github.com/llvm/llvm-project/commit/b2ba6867eac10874bd279c739639bdb9e60c1996.diff

LOG: Refactoring the attribute plugin example to fit the new API

Make the example compile and the test case pass.

Added: 
    

Modified: 
    clang/examples/Attribute/Attribute.cpp
    clang/test/Frontend/plugin-attribute.cpp

Removed: 
    


################################################################################
diff  --git a/clang/examples/Attribute/Attribute.cpp b/clang/examples/Attribute/Attribute.cpp
index 998f175dae54..159b09e4b154 100644
--- a/clang/examples/Attribute/Attribute.cpp
+++ b/clang/examples/Attribute/Attribute.cpp
@@ -23,9 +23,10 @@ namespace {
 
 struct ExampleAttrInfo : public ParsedAttrInfo {
   ExampleAttrInfo() {
-    // Can take an optional string argument (the check that the argument
-    // actually is a string happens in handleDeclAttribute).
-    OptArgs = 1;
+    // Can take up to 15 optional arguments, to emulate accepting a variadic
+    // number of arguments. This just illustrates how many arguments a
+    // `ParsedAttrInfo` can hold, we will not use that much in this example.
+    OptArgs = 15;
     // GNU-style __attribute__(("example")) and C++-style [[example]] and
     // [[plugin::example]] supported.
     static constexpr Spelling S[] = {{ParsedAttr::AS_GNU, "example"},
@@ -39,7 +40,7 @@ struct ExampleAttrInfo : public ParsedAttrInfo {
     // This attribute appertains to functions only.
     if (!isa<FunctionDecl>(D)) {
       S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type_str)
-        << Attr << "functions";
+          << Attr << "functions";
       return false;
     }
     return true;
@@ -55,23 +56,39 @@ struct ExampleAttrInfo : public ParsedAttrInfo {
       S.Diag(Attr.getLoc(), ID);
       return AttributeNotApplied;
     }
-    // Check if we have an optional string argument.
-    StringRef Str = "";
+    // 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) {
-      Expr *ArgExpr = Attr.getArgAsExpr(0);
+      auto *Arg0 = Attr.getArgAsExpr(0);
       StringLiteral *Literal =
-          dyn_cast<StringLiteral>(ArgExpr->IgnoreParenCasts());
-      if (Literal) {
-        Str = Literal->getString();
-      } else {
-        S.Diag(ArgExpr->getExprLoc(), diag::err_attribute_argument_type)
-            << Attr.getAttrName() << AANT_ArgumentString;
+          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));
+      }
+      D->addAttr(AnnotateAttr::Create(S.Context, "example", ArgsBuf.data(),
+                                      ArgsBuf.size(), Attr.getRange()));
+    } else {
+      // Attach an annotate attribute to the Decl.
+      D->addAttr(AnnotateAttr::Create(S.Context, "example", nullptr, 0,
+                                      Attr.getRange()));
     }
-    // Attach an annotate attribute to the Decl.
-    D->addAttr(AnnotateAttr::Create(S.Context, "example(" + Str.str() + ")",
-                                    Attr.getRange()));
     return AttributeApplied;
   }
 };

diff  --git a/clang/test/Frontend/plugin-attribute.cpp b/clang/test/Frontend/plugin-attribute.cpp
index 571ede3dc0b1..969105927be5 100644
--- a/clang/test/Frontend/plugin-attribute.cpp
+++ b/clang/test/Frontend/plugin-attribute.cpp
@@ -1,25 +1,22 @@
-// RUN: %clang -fplugin=%llvmshlibdir/Attribute%pluginext -emit-llvm -S %s -o - 2>&1 | FileCheck %s --check-prefix=ATTRIBUTE
-// RUN: not %clang -fplugin=%llvmshlibdir/Attribute%pluginext -emit-llvm -DBAD_ATTRIBUTE -S %s -o - 2>&1 | FileCheck %s --check-prefix=BADATTRIBUTE
+// RUN: split-file %s %t
+// RUN: %clang -cc1 -load %llvmshlibdir/Attribute%pluginext -fsyntax-only -ast-dump -verify %t/good_attr.cpp | FileCheck %s
+// RUN: %clang -fplugin=%llvmshlibdir/Attribute%pluginext -fsyntax-only -Xclang -verify %t/bad_attr.cpp
 // 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"
+// 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
 
-void fn1a() __attribute__((example)) { }
-[[example]] void fn1b() { }
-[[plugin::example]] void fn1c() { }
-void fn2() __attribute__((example("somestring"))) { }
-// ATTRIBUTE: warning: 'example' attribute only applies to functions
-int var1 __attribute__((example("otherstring"))) = 1;
-
-// ATTRIBUTE: [[STR1_VAR:@.+]] = private unnamed_addr constant [10 x i8] c"example()\00"
-// ATTRIBUTE: [[STR2_VAR:@.+]] = private unnamed_addr constant [20 x i8] c"example(somestring)\00"
-// ATTRIBUTE: @llvm.global.annotations = {{.*}}@{{.*}}fn1a{{.*}}[[STR1_VAR]]{{.*}}@{{.*}}fn1b{{.*}}[[STR1_VAR]]{{.*}}@{{.*}}fn1c{{.*}}[[STR1_VAR]]{{.*}}@{{.*}}fn2{{.*}}[[STR2_VAR]]
-
-#ifdef BAD_ATTRIBUTE
+//--- bad_attr.cpp
+int var1 __attribute__((example("otherstring"))) = 1; // expected-warning {{'example' attribute only applies to functions}}
 class Example {
-  // BADATTRIBUTE: error: 'example' attribute only allowed at file scope
-  void __attribute__((example)) fn3();
+  void __attribute__((example)) fn3(); // expected-error {{'example' attribute only allowed at file scope}}
 };
-// BADATTRIBUTE: error: 'example' attribute requires a string
-void fn4() __attribute__((example(123))) { }
-// BADATTRIBUTE: error: 'example' attribute takes no more than 1 argument
-void fn5() __attribute__((example("a","b"))) { }
-#endif
+void fn4() __attribute__((example(123))) { } // expected-error {{'example's first argument should be a string literal}}
+void fn5() __attribute__((example("a","b", 3, 4.0))) { } // expected-error {{'example' attribute only allowed at most three arguments}}


        


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