[flang-commits] [flang] [flang][OpenMP] Make parsing of trait properties more context-sensitive (PR #122900)
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flang-commits at lists.llvm.org
Tue Jan 14 05:29:37 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-flang-parser
Author: Krzysztof Parzyszek (kparzysz)
<details>
<summary>Changes</summary>
A trait poperty can be one of serveral alternatives (name, expression, etc.), and each property in a list was parsed as if it could be any of these alternatives independently from other properties. This made the parsing vulnerable to certain ambiguities in the trait grammar (provided in the OpenMP spec).
At the same time the OpenMP spec gives the expected types of properties for almost every trait: all properties listed for a given trait are usually of the same type, e.g. names, clauses, etc.
Incorporate these restrictions into the parser, and additionally use property extensions as the fallback if the parsing of the expected property type failed. This is intended to allow the parser to succeed, and instead let the semantic-checking code emit a more user-friendly message.
---
Full diff: https://github.com/llvm/llvm-project/pull/122900.diff
4 Files Affected:
- (modified) flang/include/flang/Parser/dump-parse-tree.h (+1-1)
- (modified) flang/include/flang/Parser/parse-tree.h (+13-27)
- (modified) flang/lib/Parser/openmp-parsers.cpp (+99-26)
- (modified) flang/lib/Parser/unparse.cpp (+3-2)
``````````diff
diff --git a/flang/include/flang/Parser/dump-parse-tree.h b/flang/include/flang/Parser/dump-parse-tree.h
index 11725991e9c9a9..49eeed0e7b4393 100644
--- a/flang/include/flang/Parser/dump-parse-tree.h
+++ b/flang/include/flang/Parser/dump-parse-tree.h
@@ -479,7 +479,7 @@ class ParseTreeDumper {
NODE(parser, OmpTraitPropertyName)
NODE(parser, OmpTraitScore)
NODE(parser, OmpTraitPropertyExtension)
- NODE(OmpTraitPropertyExtension, ExtensionValue)
+ NODE(OmpTraitPropertyExtension, Complex)
NODE(parser, OmpTraitProperty)
NODE(parser, OmpTraitSelectorName)
NODE_ENUM(OmpTraitSelectorName, Value)
diff --git a/flang/include/flang/Parser/parse-tree.h b/flang/include/flang/Parser/parse-tree.h
index 00d85aa05fb3a5..f8175ea1de679e 100644
--- a/flang/include/flang/Parser/parse-tree.h
+++ b/flang/include/flang/Parser/parse-tree.h
@@ -3505,37 +3505,22 @@ struct OmpTraitScore {
};
// trait-property-extension ->
-// trait-property-name (trait-property-value, ...)
-// trait-property-value ->
// trait-property-name |
-// scalar-integer-expression |
-// trait-property-extension
-//
-// The grammar in OpenMP 5.2+ spec is ambiguous, the above is a different
-// version (but equivalent) that doesn't have ambiguities.
-// The ambiguity is in
-// trait-property:
-// trait-property-name <- (a)
-// trait-property-clause
-// trait-property-expression <- (b)
-// trait-property-extension <- this conflicts with (a) and (b)
-// trait-property-extension:
-// trait-property-name <- conflict with (a)
-// identifier(trait-property-extension[, trait-property-extension[, ...]])
-// constant integer expression <- conflict with (b)
+// scalar-expr |
+// trait-property-name (trait-property-extension, ...)
//
struct OmpTraitPropertyExtension {
CharBlock source;
- TUPLE_CLASS_BOILERPLATE(OmpTraitPropertyExtension);
- struct ExtensionValue {
+ UNION_CLASS_BOILERPLATE(OmpTraitPropertyExtension);
+ struct Complex { // name (prop-ext, prop-ext, ...)
CharBlock source;
- UNION_CLASS_BOILERPLATE(ExtensionValue);
- std::variant<OmpTraitPropertyName, ScalarExpr,
- common::Indirection<OmpTraitPropertyExtension>>
- u;
+ TUPLE_CLASS_BOILERPLATE(Complex);
+ std::tuple<OmpTraitPropertyName,
+ std::list<common::Indirection<OmpTraitPropertyExtension>>>
+ t;
};
- using ExtensionList = std::list<ExtensionValue>;
- std::tuple<OmpTraitPropertyName, ExtensionList> t;
+
+ std::variant<OmpTraitPropertyName, ScalarExpr, Complex> u;
};
// trait-property ->
@@ -3568,9 +3553,10 @@ struct OmpTraitProperty {
// UID | T // unique-string-id /impl-defined
// VENDOR | I // name-list (vendor-id /add-def-doc)
// EXTENSION | I // name-list (ext_name /impl-defined)
-// ATOMIC_DEFAULT_MEM_ORDER I | // value of admo
+// ATOMIC_DEFAULT_MEM_ORDER I | // clause-list (value of admo)
// REQUIRES | I // clause-list (from requires)
// CONDITION U // logical-expr
+// <other name> I // treated as extension
//
// Trait-set-selectors:
// [D]evice, [T]arget_device, [C]onstruct, [I]mplementation, [U]ser.
@@ -3579,7 +3565,7 @@ struct OmpTraitSelectorName {
UNION_CLASS_BOILERPLATE(OmpTraitSelectorName);
ENUM_CLASS(Value, Arch, Atomic_Default_Mem_Order, Condition, Device_Num,
Extension, Isa, Kind, Requires, Simd, Uid, Vendor)
- std::variant<Value, llvm::omp::Directive> u;
+ std::variant<Value, llvm::omp::Directive, std::string> u;
};
// trait-selector ->
diff --git a/flang/lib/Parser/openmp-parsers.cpp b/flang/lib/Parser/openmp-parsers.cpp
index 5ff91da082c852..a7b3986845d985 100644
--- a/flang/lib/Parser/openmp-parsers.cpp
+++ b/flang/lib/Parser/openmp-parsers.cpp
@@ -158,31 +158,23 @@ static TypeDeclarationStmt makeIterSpecDecl(std::list<ObjectName> &&names) {
static std::string nameToString(Name &&name) { return name.ToString(); }
TYPE_PARSER(sourced(construct<OmpTraitPropertyName>( //
- (space >> charLiteralConstantWithoutKind) ||
- applyFunction(nameToString, Parser<Name>{}))))
+ construct<OmpTraitPropertyName>(space >> charLiteralConstantWithoutKind) ||
+ construct<OmpTraitPropertyName>(
+ applyFunction(nameToString, Parser<Name>{})))))
TYPE_PARSER(sourced(construct<OmpTraitScore>( //
- "SCORE" >> parenthesized(scalarIntExpr))))
+ "SCORE"_tok >> parenthesized(scalarIntExpr))))
-TYPE_PARSER(sourced(construct<OmpTraitPropertyExtension::ExtensionValue>(
- // Parse nested extension first.
- construct<OmpTraitPropertyExtension::ExtensionValue>(
- indirect(Parser<OmpTraitPropertyExtension>{})) ||
- construct<OmpTraitPropertyExtension::ExtensionValue>(
- Parser<OmpTraitPropertyName>{}) ||
- construct<OmpTraitPropertyExtension::ExtensionValue>(scalarExpr))))
-
-TYPE_PARSER(sourced(construct<OmpTraitPropertyExtension>( //
+TYPE_PARSER(sourced(construct<OmpTraitPropertyExtension::Complex>(
Parser<OmpTraitPropertyName>{},
parenthesized(nonemptySeparated(
- Parser<OmpTraitPropertyExtension::ExtensionValue>{}, ","_tok)))))
+ indirect(Parser<OmpTraitPropertyExtension>{}), ","_tok)))))
-TYPE_PARSER(sourced(construct<OmpTraitProperty>(
- // Try clause first, then extension before OmpTraitPropertyName.
- construct<OmpTraitProperty>(indirect(Parser<OmpClause>{})) ||
- construct<OmpTraitProperty>(Parser<OmpTraitPropertyExtension>{}) ||
- construct<OmpTraitProperty>(Parser<OmpTraitPropertyName>{}) ||
- construct<OmpTraitProperty>(scalarExpr))))
+TYPE_PARSER(sourced(construct<OmpTraitPropertyExtension>(
+ construct<OmpTraitPropertyExtension>(
+ Parser<OmpTraitPropertyExtension::Complex>{}) ||
+ construct<OmpTraitPropertyExtension>(Parser<OmpTraitPropertyName>{}) ||
+ construct<OmpTraitPropertyExtension>(scalarExpr))))
TYPE_PARSER(construct<OmpTraitSelectorName::Value>(
"ARCH" >> pure(OmpTraitSelectorName::Value::Arch) ||
@@ -201,15 +193,96 @@ TYPE_PARSER(construct<OmpTraitSelectorName::Value>(
TYPE_PARSER(sourced(construct<OmpTraitSelectorName>(
// Parse predefined names first (because of SIMD).
construct<OmpTraitSelectorName>(Parser<OmpTraitSelectorName::Value>{}) ||
- construct<OmpTraitSelectorName>(OmpDirectiveNameParser{}))))
+ construct<OmpTraitSelectorName>(OmpDirectiveNameParser{}) ||
+ // identifier-or-string for extensions
+ construct<OmpTraitSelectorName>(
+ applyFunction(nameToString, Parser<Name>{})) ||
+ construct<OmpTraitSelectorName>(space >> charLiteralConstantWithoutKind))))
+
+// Parser for OmpTraitSelector::Properties
+template <typename... PropParser>
+static constexpr auto propertyListParser(PropParser... pp) {
+ // Parse the property list "(score(expr): item1...)" in three steps:
+ // 1. Parse the "("
+ // 2. Parse the optional "score(expr):"
+ // 3. Parse the "item1, ...)", together with the ")".
+ // The reason for including the ")" in the 3rd step is to force parsing
+ // the entire list in each of the alternative property parsers. Otherwise,
+ // the name parser could stop after "foo" in "(foo, bar(1))", without
+ // allowing the next parser to give the list a try.
+
+ using P = OmpTraitProperty;
+ return maybe("(" >>
+ construct<OmpTraitSelector::Properties>(
+ maybe(Parser<OmpTraitScore>{} / ":"_tok),
+ (attempt(nonemptySeparated(construct<P>(pp), ","_tok) / ")"_tok) ||
+ ...)));
+}
+
+// Parser for OmpTraitSelector
+struct TraitSelectorParser {
+ using resultType = OmpTraitSelector;
+
+ constexpr TraitSelectorParser(Parser<OmpTraitSelectorName> p) : np(p) {}
+
+ std::optional<resultType> Parse(ParseState &state) const {
+ auto name{attempt(np).Parse(state)};
+ if (!name.has_value()) {
+ return std::nullopt;
+ }
+
+ // Default fallback parser for lists that cannot be parser using the
+ // primary property parser.
+ auto extParser{Parser<OmpTraitPropertyExtension>{}};
+
+ if (auto *v{std::get_if<OmpTraitSelectorName::Value>(&name->u)}) {
+ switch (*v) {
+ // name-list properties
+ case OmpTraitSelectorName::Value::Arch: // [6.0:319:18]
+ case OmpTraitSelectorName::Value::Extension: // [6.0:319:30]
+ case OmpTraitSelectorName::Value::Isa: // [6.0:319:15]
+ case OmpTraitSelectorName::Value::Kind: // [6.0:319:10]
+ case OmpTraitSelectorName::Value::Uid: // [6.0:319:23](*)
+ case OmpTraitSelectorName::Value::Vendor: { // [6.0:319:27]
+ auto pp{propertyListParser(Parser<OmpTraitPropertyName>{}, extParser)};
+ return OmpTraitSelector(std::move(*name), std::move(*pp.Parse(state)));
+ }
+ // clause-list
+ case OmpTraitSelectorName::Value::Atomic_Default_Mem_Order:
+ // [6.0:321:26-29](*)
+ case OmpTraitSelectorName::Value::Requires: // [6.0:319:33]
+ case OmpTraitSelectorName::Value::Simd: { // [6.0:318:31]
+ auto pp{propertyListParser(indirect(Parser<OmpClause>{}), extParser)};
+ return OmpTraitSelector(std::move(*name), std::move(*pp.Parse(state)));
+ }
+ // expr-list
+ case OmpTraitSelectorName::Value::Condition: // [6.0:321:33](*)
+ case OmpTraitSelectorName::Value::Device_Num: { // [6.0:321:23-24](*)
+ auto pp{propertyListParser(scalarExpr, extParser)};
+ return OmpTraitSelector(std::move(*name), std::move(*pp.Parse(state)));
+ }
+ // (*) The spec doesn't assign any list-type to these traits, but for
+ // convenience they can be treated as if they were.
+ } // switch
+ } else {
+ // The other alternatives are `llvm::omp::Directive`, and `std::string`.
+ // The former doesn't take any properties[1], the latter is a name of an
+ // extension[2].
+ // [1] [6.0:319:1-2]
+ // [2] [6.0:319:36-37]
+ auto pp{propertyListParser(extParser)};
+ return OmpTraitSelector(std::move(*name), std::move(*pp.Parse(state)));
+ }
-TYPE_PARSER(construct<OmpTraitSelector::Properties>(
- maybe(Parser<OmpTraitScore>{} / ":"_tok),
- nonemptySeparated(Parser<OmpTraitProperty>{}, ","_tok)))
+ llvm_unreachable("Unhandled trait name?");
+ }
+
+private:
+ const Parser<OmpTraitSelectorName> np;
+};
-TYPE_PARSER(sourced(construct<OmpTraitSelector>( //
- Parser<OmpTraitSelectorName>{}, //
- maybe(parenthesized(Parser<OmpTraitSelector::Properties>{})))))
+TYPE_PARSER(construct<OmpTraitSelector>(
+ TraitSelectorParser(Parser<OmpTraitSelectorName>{})))
TYPE_PARSER(construct<OmpTraitSetSelectorName::Value>(
"CONSTRUCT" >> pure(OmpTraitSetSelectorName::Value::Construct) ||
diff --git a/flang/lib/Parser/unparse.cpp b/flang/lib/Parser/unparse.cpp
index 7bf404bba2c3e4..af5259e1daec43 100644
--- a/flang/lib/Parser/unparse.cpp
+++ b/flang/lib/Parser/unparse.cpp
@@ -2075,10 +2075,11 @@ class UnparseVisitor {
Walk(x.v);
Put(")");
}
- void Unparse(const OmpTraitPropertyExtension &x) {
+ void Unparse(const OmpTraitPropertyExtension::Complex &x) {
+ using PropList = std::list<common::Indirection<OmpTraitPropertyExtension>>;
Walk(std::get<OmpTraitPropertyName>(x.t));
Put("(");
- Walk(std::get<OmpTraitPropertyExtension::ExtensionList>(x.t), ",");
+ Walk(std::get<PropList>(x.t), ",");
Put(")");
}
void Unparse(const OmpTraitSelector &x) {
``````````
</details>
https://github.com/llvm/llvm-project/pull/122900
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