tools/frr-llvm-debuginfo.cpp

   1 // SPDX-License-Identifier: Unlicense
   2
   3 #include <llvm-c/BitReader.h>
   4 #include <llvm-c/BitWriter.h>
   5 #include <llvm-c/Core.h>
   6 #include <llvm-c/DebugInfo.h>
   7
   8 #include <llvm/IR/Module.h>
   9 #include <llvm/IR/Value.h>
  10 #include <llvm/IR/Type.h>
  11 #include <llvm/IR/DebugInfo.h>
  12 #include <llvm/IR/DebugInfoMetadata.h>
  13 #include <llvm/Support/raw_ostream.h>
  14
  15 #include <map>
  16
  17 #include "frr-llvm-debuginfo.h"
  18
  19 /* llvm::DebugInfoFinder is unfortunately not exposed in the llvm-c API... */
  20
  21 struct dbginfo {
  22         llvm::DebugInfoFinder finder;
  23         std::map<std::string, llvm::DICompositeType *> tab;
  24 };
  25
  26 struct dbginfo *dbginfo_load(LLVMModuleRef _mod)
  27 {
  28         llvm::Module *mod = llvm::unwrap(_mod);
  29         struct dbginfo *info = new dbginfo();
  30
  31         info->finder.processModule(*mod);
  32
  33         for (auto ty : info->finder.types()) {
  34                 if (ty->getMetadataID() != llvm::Metadata::DICompositeTypeKind)
  35                         continue;
  36
  37                 llvm::DICompositeType *cty = (llvm::DICompositeType *)ty;
  38                 /* empty forward declarations aka "struct foobar;" */
  39                 if (cty->getElements().size() == 0)
  40                         continue;
  41
  42                 info->tab.emplace(std::move(ty->getName().str()), cty);
  43         }
  44
  45         return info;
  46 }
  47
  48 bool dbginfo_struct_member(struct dbginfo *info, LLVMTypeRef _typ,
  49                            unsigned long long idx, char **struct_name,
  50                            char **member_name)
  51 {
  52         *struct_name = NULL;
  53         *member_name = NULL;
  54
  55         llvm::Type *typ = llvm::unwrap(_typ);
  56
  57         if (!typ->isStructTy())
  58                 return false;
  59
  60         llvm::StructType *styp = (llvm::StructType *)typ;
  61         auto sname = styp->getStructName();
  62
  63         if (!sname.startswith("struct."))
  64                 return false;
  65         sname = sname.drop_front(7);
  66
  67         size_t dot = sname.find_last_of(".");
  68         if (dot != sname.npos)
  69                 sname = sname.take_front(dot);
  70
  71         auto item = info->tab.find(sname.str());
  72         if (item == info->tab.end())
  73                 return false;
  74
  75         auto elements = item->second->getElements();
  76         if (idx >= elements.size())
  77                 return false;
  78
  79         auto elem = elements[idx];
  80
  81         if (elem->getMetadataID() != llvm::Metadata::DIDerivedTypeKind)
  82                 return false;
  83
  84         llvm::DIDerivedType *dtyp = (llvm::DIDerivedType *)elem;
  85
  86         *struct_name = strdup(sname.str().c_str());
  87         *member_name = strdup(dtyp->getName().str().c_str());
  88         return true;
  89 }