diff options
Diffstat (limited to 'libbuild2/cc/parser.cxx')
| -rw-r--r-- | libbuild2/cc/parser.cxx | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/libbuild2/cc/parser.cxx b/libbuild2/cc/parser.cxx index 690f41c..706dc48 100644 --- a/libbuild2/cc/parser.cxx +++ b/libbuild2/cc/parser.cxx @@ -30,8 +30,16 @@ namespace build2 // issue warnings. But the problem with this approach is that they are // easy to miss. So for now we fail. And it turns out we don't mis- // parse much. + + // We keep a {}-balance and skip everything at depth 1 and greater. + // While after P1703 and P1857 everything that we are interested in + // (module and import declarations) are treated as pseudo-pp-directives + // and recognized everywhere, they are illegal everywhere execept at + // depth 0. So we are going to skip for performance reasons and expect + // the compiler to complain about the syntax rather than, say, module + // BMI not being found. // - size_t bb (0); // {}-balance. + int64_t bb (0); token t; for (bool n (true); (n ? l_->next (t) : t.type) != type::eos; ) @@ -50,7 +58,7 @@ namespace build2 } case type::rcbrace: { - if (bb-- == 0) + if (--bb < 0) break; // Imbalance. continue; @@ -60,9 +68,9 @@ namespace build2 // Constructs we need to recognize: // // module ; + // [export] module <module-name> [<attributes>] ; // [export] import <module-name> [<attributes>] ; // [export] import <header-name> [<attributes>] ; - // [export] module <module-name> [<attributes>] ; // // Additionally, when include is translated to an import, it's // normally replaced with the special __import keyword since it @@ -100,8 +108,21 @@ namespace build2 break; } + // We used to issue an error here but the diagnostics and, especially, + // the location are not very helpful. While the compilers don't do a + // much better job at it, there are often other semantic errors that are + // more helpful and which we cannot match. So now we warn and let the + // compiler fail. + // + // Another option would have been to postpone this diagnostics until + // after the compiler fails (and thus also confirming that it indeed has + // failed) but that would require propagating this state from apply() to + // perform_update() and also making sure we issue this diagnostics even + // if anything in between fails (probably by having it sitting in a + // diag_frame). So let's keep it simple for now. + // if (bb != 0) - /*warn*/ fail (t) << "{}-imbalance detected"; + warn (t) << (bb > 0 ? "missing '}'" : "extraneous '}'"); if (module_marker_ && u.module_info.name.empty ()) fail (*module_marker_) << "module declaration expected after " |