robotpy-cppheaderparser
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robotpy
Unions nested inside structures are not parsed
Hello everyone! Thank you for maintaining this library, and fixing various bugs with the original library. I am trying to parse headers with a anonymous union defined inside a struct :
typedef struct
{
volatile union
{
volatile uint8_t u8;
volatile uint16_t u16;
volatile uint32_t u32;
} PORT [32];
uint32_t RESERVED0[864];
volatile uint32_t TER;
.....
} ITM_Type;
However, this union is not parsed as such, and i have no way of isolating the data allocated inside the union from the rest of the structure. Output, printed as another C header gives :
typedef struct ITM_Type
{
volatile uint8_t u8;
volatile uint16_t u16;
volatile uint32_t u32;
PORT ;
uint32_t RESERVED0;
volatile uint32_t TER;
.....
} ITM_Type;
As you can see the resulting memory allocated is not correct.
The output in json is :
{
"headerFileName": "report_issue/input_union.h",
"curClass": "",
"classes": {
"ITM_Type": {
"nested_classes": [],
"abstract": false,
"final": false,
"namespace": "",
"using": {},
"name": "ITM_Type",
"bare_name": "<anon-struct-1>",
"inherits": [],
"filename": "report_issue/input_union.h",
"line_number": 2,
"methods": {
"public": [],
"protected": [],
"private": []
},
"properties": {
"public": [
{
"extern": false,
"array": 0,
"filename": "report_issue/input_union.h",
"line_number": 6,
"function_pointer": 0,
"type": "volatile uint8_t",
"name": "u8",
"aliases": [
"volatile"
],
"typedef": null,
"constant": 0,
"constexpr": 0,
"reference": 0,
"pointer": 0,
"static": 0,
"typedefs": 0,
"class": 0,
"fundamental": 0,
"unresolved": true,
"namespace": "",
"property_of_class": "<anon-struct-1>",
"mutable": false,
"raw_type": "volatile uint8_t"
},
{
"extern": false,
"array": 0,
"filename": "report_issue/input_union.h",
"line_number": 7,
"function_pointer": 0,
"type": "volatile uint16_t",
"name": "u16",
"aliases": [
"volatile"
],
"typedef": null,
"constant": 0,
"constexpr": 0,
"reference": 0,
"pointer": 0,
"static": 0,
"typedefs": 0,
"class": 0,
"fundamental": 0,
"unresolved": true,
"namespace": "",
"property_of_class": "<anon-struct-1>",
"mutable": false,
"raw_type": "volatile uint16_t"
},
{
"extern": false,
"array": 0,
"filename": "report_issue/input_union.h",
"line_number": 8,
"function_pointer": 0,
"type": "volatile uint32_t",
"name": "u32",
"aliases": [
"volatile"
],
"typedef": null,
"constant": 0,
"constexpr": 0,
"reference": 0,
"pointer": 0,
"static": 0,
"typedefs": 0,
"class": 0,
"fundamental": 0,
"unresolved": true,
"namespace": "",
"property_of_class": "<anon-struct-1>",
"mutable": false,
"raw_type": "volatile uint32_t"
},
{
"extern": false,
"array_size": "32",
"array": 1,
"filename": "report_issue/input_union.h",
"line_number": 9,
"function_pointer": 0,
"type": "PORT",
"name": "",
"aliases": [
"PORT"
],
"typedef": null,
"constant": 0,
"constexpr": 0,
"reference": 0,
"pointer": 0,
"static": 0,
"typedefs": 0,
"class": 0,
"fundamental": 0,
"unresolved": true,
"namespace": "",
"property_of_class": "<anon-struct-1>",
"mutable": false,
"raw_type": "PORT"
},
{
"extern": false,
"array_size": "864",
"array": 1,
"filename": "report_issue/input_union.h",
"line_number": 10,
"function_pointer": 0,
"type": "uint32_t",
"name": "RESERVED0",
"aliases": [
"uint32_t"
],
"typedef": null,
"constant": 0,
"constexpr": 0,
"reference": 0,
"pointer": 0,
"static": 0,
"typedefs": 0,
"class": 0,
"fundamental": 0,
"unresolved": true,
"namespace": "",
"property_of_class": "<anon-struct-1>",
"mutable": false,
"raw_type": "uint32_t"
},
{
"extern": false,
"array": 0,
"filename": "report_issue/input_union.h",
"line_number": 11,
"function_pointer": 0,
"type": "volatile uint32_t",
"name": "TER",
"aliases": [
"volatile"
],
"typedef": null,
"constant": 0,
"constexpr": 0,
"reference": 0,
"pointer": 0,
"static": 0,
"typedefs": 0,
"class": 0,
"fundamental": 0,
"unresolved": true,
"namespace": "",
"property_of_class": "<anon-struct-1>",
"mutable": false,
"raw_type": "volatile uint32_t"
},
],
"protected": [],
"private": []
},
"enums": {
"public": [],
"protected": [],
"private": []
},
"typedefs": {
"public": [],
"protected": [],
"private": []
},
"forward_declares": {
"public": [],
"protected": [],
"private": []
},
"declaration_method": "struct"
}
},
"functions": [],
"pragmas": [],
"defines": [],
"includes": [],
"headerFileNames": [
"report_issue/input_union.h"
],
"enums": [],
"variables": [],
"global_enums": {},
"typedefs": {},
"namespaces": [],
"using": {}
}
Thanks in advance for any help
Definitely a bug. I don't really have an interest in fixing this myself (lots of stuff going on), but I can provide guidance for debugging/fixing this if you would like to fix it.
I had a lookat the parsing method, it appears that the method evaluate_class_stack expects only one keyword in the declaration (in my case it was not recognized because the union is volatile.
I can try to change this behavior and use if "struct" in self.nameStack etc in :
def _evaluate_class_stack(self):
parent = self.curClass
if parent:
debug_print("found nested subclass")
self.accessSpecifierStack.append(self.curAccessSpecifier)
if self.nameStack[0] == "typedef":
del self.nameStack[0]
if len(self.nameStack) == 1:
if self.nameStack[0] == "struct":
self.anon_struct_counter += 1
# We cant handle more than 1 anonymous struct, so name them uniquely
self.nameStack.append("anon-struct-%d" % self.anon_struct_counter)
elif self.nameStack[0] == "union":
self.anon_union_counter += 1
# We cant handle more than 1 anonymous union, so name them uniquely
self.nameStack.append("anon-union-%d" % self.anon_union_counter)
However, when I try with only a union declarator, the class is parsed, but not its instance in the structure. In my case, I have an array of unions, and the parser does not see it.
I find that setting the environment variable CPPHEADERPARSER_DEBUG=1 is really useful for figuring out what the parser is doing.
I used this to investigate a little bit, this is my debug log : for my array
[3192] <anon-struct-10> (public)
[3228] trace (Empty Stack)
[3181] Evaluating stack ['PORT', '[', '32', ']']
BraceDepth: 1 (called from 2952)
[3192] <anon-struct-10> (public)
[3312] trace
[2356] trace
[1186] var trace ['PORT', '[', '32', ']']
[1209] Array
[1221] Variable: ['PORT']
for a nested structure in the same file
[3192] <anon-union-1>::<anon-struct-2> (public)
[3228] trace (Empty Stack)
[3181] Evaluating stack ['b']
BraceDepth: 1 (called from 2952)
[3192] <anon-union-1> (public)
[3312] trace
[2356] trace
[2383] DEANONYMOIZING b to type '<anon-struct-2>'
[1186] var trace ['<anon-struct-2>', 'b']
[1221] Variable: ['<anon-struct-2>', 'b']
[3181] Evaluating stack ['uint32_t', 'w']
BraceDepth: 1 (called from 2952)
from my comprehension, the parser gets to the line 2371, where it decides what to do with the variable.
- if the variable declaration has a length of 1, it checks for nested class types.
- if not, it just declares a variable, assuming that the first keyword is the type.
Hence it goes to the declaration of a
CppVariableand sets the flags for an array of variables.
So my second issue here is that i can not parse an array of nested classes.
I don't know if just changing the condition to ( len(self.nameStack) == 1 or self.nameStack[1]=="[") would correct this or if it breaks a few things in the library. I try the 2 modifications and make a few checks.
So I made a pull request with a few changes that should not break anything.
This bug is made of 2 problems :
- The parser does not parse nested classes with preprocessor keywords
- The parser does not parse arrays of nested classes
the second issue should be adressed in the PR but the first one needs deeper changes