Opened 7 years ago
Last modified 7 years ago
#11 new defect
Compiler uses all Resources when Copying from Generic Function Result
Reported by: | ajbeach | Owned by: | |
---|---|---|---|
Priority: | minor | Component: | cfa-cc |
Version: | 1.0 | Keywords: | |
Cc: |
Description
If I try to compile the following code the cfa compiler uses 100% CPU and 100% MEM and crashes the computer.
maybe(char) letter = maybe_value('a');
However the following code compiles with no noticeable slowdown:
maybe(char) letter; letter = maybe_value('a'); maybe(char) rune = letter;
I also tried annotating the argument, (char)'a', and that got it to work. I'm not sure why as under the current rules that should be a no-op. But it does suggest a resolver issue.
I also tried annotating the call of maybe_value with maybe(char) and got the following error:
*CFA assertion error* from program "cfa-cpp" in "virtual void CodeGen::CodeGenerator::visit(TypeExpr*)" at line 733 in file "CodeGen/CodeGenerator.cc": TypeExpr should not reach code generation. Stack back trace for: /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp (0) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::CodeGenerator::visit(TypeExpr*)+0xd2 [0x4630d2] (1) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::GenType::handleGeneric[abi:cxx11](ReferenceToType*)+0x206 [0x468d56] (2) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::GenType::visit(StructInstType*)+0x32 [0x46b6f2] (3) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::genType(Type*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool, bool, bool)+0x1fc [0x4691ac] (4) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::CodeGenerator::visit(ObjectDecl*)+0xa7 [0x467247] (5) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::CodeGenerator::visit(DeclStmt*)+0x18 [0x4636d8] (6) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::CodeGenerator::visit(CompoundStmt*)+0x16c [0x46665c] (7) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::CodeGenerator::visit(FunctionDecl*)+0xef [0x4670af] (8) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : CodeGen::generate(std::__cxx11::list<Declaration*, std::allocator<Declaration*> >, std::ostream&, bool, bool, bool, bool)+0x80 [0x462be0] (9) /home/ajbeach/cfa-cc/lib/cfa/cfa-cpp : main(/*unknown*/)+0x89f [0x45c37f] CFA Translator error: cfa-cpp failed with signal 6
Some related maybe function definitions (from the new containers/maybe library header)
forall(otype T) void ?{}(maybe(T) * this, maybe(T) other); forall(otype T) maybe(T) ?=?(maybe(T) * this, maybe(T) other); forall(otype T) maybe(T) maybe_value(T value);
Change History (3)
comment:1 Changed 7 years ago by
comment:2 Changed 7 years ago by
The issue with the code above seems to actually be maybe(char) rune = maybe_none();
The existing resolver is not good at inferring types that don't exist in the parameter list of the function, though I can perhaps take a look at this.
As a workaround for this case, maybe(char) rune = {};
should work.
Andrew pointed out that the following also don't work, I strongly suspect it's the same underlying bug (the error and value types, respectively, are not bound in the parameter list):
result(int, char) answer = result_value( 42 ); result(int, char) nonanswer = result_error( '!' );
Workarounds for the above cases are as follows:
result(int, char) answer = { 1, 42 }; result(int, char) nonanswer = { 0, '!' };
It is worth noting that the resolver prototype already handles these cases (more or less, it doesn't support generic types yet, but it does do inference over return types).
comment:3 Changed 7 years ago by
Smallest reproduction of this bug (works under -XCFA -n
no-prelude compilation, and if you comment out line 4 it doesn't occur):
Sorry, may have cut too much out of the context. This still seems to cause problems.