How do I add an attribute alias to LLVM (add targeted support)?

I am working on adding AVR target to LLVM and Clang . Now I have to add support __attribute__ ((progmem))

.

The first thing I tried to do was add a new attribute to Attr.td

:

def TargetAVR : TargetArch<["avr"]>;
def AVRProgmem : InheritableAttr, TargetSpecificAttr<TargetAVR> {
  let Spellings = [GCC<"progmem">];
  let Subjects = SubjectList<[Function, GlobalVar], ErrorDiag,
                             "ExpectedFunctionGlobalVarMethodOrProperty">;
  let Documentation = [SectionDocs];
}

      

        
        
        
      

    

I tested it with the following code:

#include <avr/io.h>

#define PROGMEM __attribute__ ((progmem))

static const uint8_t tone_pin_to_timer_PGM[] PROGMEM = { 2 };

int main()
{
    DDRB = 0x00;        //configure portB as input
    DDRC = 0xFF;        //configure portC as output

    while(1)
    {
        PORTC = PINB;
    }
    return 0;
}

      

        
        
        
      

    

Unfortunately, this does not work because the "section" attribute is not a normal attribute, but special attributes that LLVM knows that the item it is attached to should be placed in a specific section.

Assertion failed: (Attr.isTypeAttr() && "Non-type attribute not handled"), function ProcessDeclAttribute, file /Users/asmirnov/Documents/dev/src/llvm_dylan/tools/clang/lib/Sema/SemaDeclAttr.cpp, line 4232.
0  clang                    0x000000011001b72e llvm::sys::PrintStackTrace(__sFILE*) + 46
1  clang                    0x000000011001cadb PrintStackTraceSignalHandler(void*) + 27
2  clang                    0x000000011001cf25 SignalHandler(int) + 565
3  libsystem_platform.dylib 0x00007fff8fd785aa _sigtramp + 26
4  libsystem_platform.dylib 0x00007fff532b82e8 _sigtramp + 3277061464
5  clang                    0x000000011001cb0b raise + 27
6  clang                    0x000000011001cbc2 abort + 18
7  clang                    0x000000011001cba1 __assert_rtn + 129
8  clang                    0x000000010d38b415 ProcessDeclAttribute(clang::Sema&, clang::Scope*, clang::Decl*, clang::AttributeList const&, bool) + 485
9  clang                    0x000000010d38aff5 clang::Sema::ProcessDeclAttributeList(clang::Scope*, clang::Decl*, clang::AttributeList const*, bool) + 101
10 clang                    0x000000010d38d3e1 clang::Sema::ProcessDeclAttributes(clang::Scope*, clang::Decl*, clang::Declarator const&) + 273
11 clang                    0x000000010d347d8d clang::Sema::ActOnVariableDeclarator(clang::Scope*, clang::Declarator&, clang::DeclContext*, clang::TypeSourceInfo*, clang::LookupResult&, llvm::MutableArrayRef<clang::TemplateParameterList*>, bool&) + 6845
12 clang                    0x000000010d340dbe clang::Sema::HandleDeclarator(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>) + 3214
13 clang                    0x000000010d3400ae clang::Sema::ActOnDeclarator(clang::Scope*, clang::Declarator&) + 94
14 clang                    0x000000010d1199c7 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) + 215
15 clang                    0x000000010d118a29 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, unsigned int, bool, clang::SourceLocation*, clang::Parser::ForRangeInit*) + 2185
16 clang                    0x000000010d1afb7c clang::Parser::ParseDeclOrFunctionDefInternal(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec&, clang::AccessSpecifier) + 1228
17 clang                    0x000000010d1af295 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*, clang::AccessSpecifier) + 197
18 clang                    0x000000010d1aea21 clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*) + 3441
19 clang                    0x000000010d1adc65 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&) + 773
20 clang                    0x000000010d1059fc clang::ParseAST(clang::Sema&, bool, bool) + 988
21 clang                    0x000000010caaf82a clang::ASTFrontendAction::ExecuteAction() + 522
22 clang                    0x000000010cface23 clang::CodeGenAction::ExecuteAction() + 3939
23 clang                    0x000000010caaeda8 clang::FrontendAction::Execute() + 120
24 clang                    0x000000010ca40a89 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 1017
25 clang                    0x000000010c964c01 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 3201
26 clang                    0x000000010c944360 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 2496
27 clang                    0x000000010c959deb ExecuteCC1Tool(llvm::ArrayRef<char const*>, llvm::StringRef) + 171
28 clang                    0x000000010c958c5b main + 1275
29 libdyld.dylib            0x00007fff8aeb05fd start + 1
30 libdyld.dylib            0x000000000000002e start + 1964309042

      

        
        
        
      

    

I don't want to copy this code, so I can make llvm know __attribute__ ((progmem))

- is this just an alias for __attribute__ ((section ("progmem") ))

?

PS. It is undesirable to use a macro, as it requires additional inclusion with macros in each source code.