HighCommander4 wrote:
I poked at this a bit more. A few more notes:
* Since the test case currently in the patch does not trigger the crash
(without the fix), and it was not obvious to me what sort of call to
`spelledForExpanded()` to formulate to trigger the crash, I instead formulated
a test case in `DumpASTTests.cpp` that calls `dumpAST()` on the
`TranslationUnitDecl` of a file containing the code `int main() {`. This does
trigger the crash.
* The crash occurs when dumping the `FunctionDecl` node for `main`. When
dumping a node, `dumpAST()`
[calls](https://searchfox.org/llvm/rev/fd1c156e5d6584684ce58c0536dca96cedcc41f0/clang-tools-extra/clangd/DumpAST.cpp#93)
`Tokens.spelledForExpanded(Tokens.expandedTokens(SR))` where `SR` is the
node's source range.
* For this `FunctionDecl` node, the end location of its source range points to
a `tok::eof` token.
* This comes from the end location of the function's `CompoundStmt` body,
which is what the parser assigns in
[Parser::ParseCompoundStatementBody()](https://searchfox.org/llvm/rev/fd1c156e5d6584684ce58c0536dca96cedcc41f0/clang/lib/Parse/ParseStmt.cpp#1292)
in this situation.
* The range of expanded tokens returned by `Tok.expandedTokens(SR)` thus
includes as its last element the `tok::eof` token.
* The
[comment](https://searchfox.org/llvm/rev/fd1c156e5d6584684ce58c0536dca96cedcc41f0/clang/include/clang/Tooling/Syntax/Tokens.h#162)
above `TokenBuffer` says "the expanded token stream has a `tok::eof` token at
the end, the spelled tokens never store a 'eof' token".
I haven't dug into the implementation of `spelledForExpanded()` yet, but from
the above it's looking to me like `spelledForExpanded()` is not expecting an
input expanded token range that includes the `eof` token, but we are passing it
one (and such a token range can legitimately arise from the source range of the
AST node in cases of invalid code like this).
https://github.com/llvm/llvm-project/pull/69849
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
