tools/frr-llvm-debuginfo.cpp

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  25
  26 #include <llvm-c/BitReader.h>
  27 #include <llvm-c/BitWriter.h>
  28 #include <llvm-c/Core.h>
  29 #include <llvm-c/DebugInfo.h>
  30
  31 #include <llvm/IR/Module.h>
  32 #include <llvm/IR/Value.h>
  33 #include <llvm/IR/Type.h>
  34 #include <llvm/IR/DebugInfo.h>
  35 #include <llvm/IR/DebugInfoMetadata.h>
  36 #include <llvm/Support/raw_ostream.h>
  37
  38 #include <map>
  39
  40 #include "frr-llvm-debuginfo.h"
  41
  42 /* llvm::DebugInfoFinder is unfortunately not exposed in the llvm-c API... */
  43
  44 struct dbginfo {
  45         llvm::DebugInfoFinder finder;
  46         std::map<std::string, llvm::DICompositeType *> tab;
  47 };
  48
  49 struct dbginfo *dbginfo_load(LLVMModuleRef _mod)
  50 {
  51         llvm::Module *mod = llvm::unwrap(_mod);
  52         struct dbginfo *info = new dbginfo();
  53
  54         info->finder.processModule(*mod);
  55
  56         for (auto ty : info->finder.types()) {
  57                 if (ty->getMetadataID() != llvm::Metadata::DICompositeTypeKind)
  58                         continue;
  59
  60                 llvm::DICompositeType *cty = (llvm::DICompositeType *)ty;
  61                 /* empty forward declarations aka "struct foobar;" */
  62                 if (cty->getElements().size() == 0)
  63                         continue;
  64
  65                 info->tab.emplace(std::move(ty->getName().str()), cty);
  66         }
  67
  68         return info;
  69 }
  70
  71 bool dbginfo_struct_member(struct dbginfo *info, LLVMTypeRef _typ,
  72                            unsigned long long idx, char **struct_name,
  73                            char **member_name)
  74 {
  75         *struct_name = NULL;
  76         *member_name = NULL;
  77
  78         llvm::Type *typ = llvm::unwrap(_typ);
  79
  80         if (!typ->isStructTy())
  81                 return false;
  82
  83         llvm::StructType *styp = (llvm::StructType *)typ;
  84         auto sname = styp->getStructName();
  85
  86         if (!sname.startswith("struct."))
  87                 return false;
  88         sname = sname.drop_front(7);
  89
  90         size_t dot = sname.find_last_of(".");
  91         if (dot != sname.npos)
  92                 sname = sname.take_front(dot);
  93
  94         auto item = info->tab.find(sname.str());
  95         if (item == info->tab.end())
  96                 return false;
  97
  98         auto elements = item->second->getElements();
  99         if (idx >= elements.size())
 100                 return false;
 101
 102         auto elem = elements[idx];
 103
 104         if (elem->getMetadataID() != llvm::Metadata::DIDerivedTypeKind)
 105                 return false;
 106
 107         llvm::DIDerivedType *dtyp = (llvm::DIDerivedType *)elem;
 108
 109         *struct_name = strdup(sname.str().c_str());
 110         *member_name = strdup(dtyp->getName().str().c_str());
 111         return true;
 112 }