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-rw-r--r--libbuild2/bin/def-rule.cxx610
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diff --git a/libbuild2/bin/def-rule.cxx b/libbuild2/bin/def-rule.cxx
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+// file : libbuild2/bin/def-rule.cxx -*- C++ -*-
+// license : MIT; see accompanying LICENSE file
+
+#include <libbuild2/bin/def-rule.hxx>
+
+#include <libbuild2/depdb.hxx>
+#include <libbuild2/scope.hxx>
+#include <libbuild2/target.hxx>
+#include <libbuild2/algorithm.hxx>
+#include <libbuild2/diagnostics.hxx>
+
+#include <libbuild2/bin/target.hxx>
+#include <libbuild2/bin/utility.hxx>
+
+namespace build2
+{
+ namespace bin
+ {
+ struct symbols
+ {
+ set<string> d; // data
+ set<string> r; // read-only data
+ set<string> b; // uninitialized data (BSS)
+ set<string> t; // text (code)
+ };
+
+ static void
+ parse_dumpbin (istream& is, symbols& syms)
+ {
+ // Lines that describe symbols look like:
+ //
+ // 0 1 2 3 4 5 6
+ // IDX OFFSET SECT SYMTYPE VISIBILITY SYMNAME
+ // ------------------------------------------------------------------------
+ // 02E 00000130 SECTA notype External | _standbyState
+ // 02F 00000009 SECT9 notype Static | _LocalRecoveryInProgress
+ // 064 00000020 SECTC notype () Static | _XLogCheckBuffer
+ // 065 00000000 UNDEF notype () External | _BufferGetTag
+ //
+ // IDX is the symbol index and OFFSET is its offset.
+ //
+ // SECT[ION] is the name of the section where the symbol is defined. If
+ // UNDEF, then it's a symbol to be resolved at link time from another
+ // object file.
+ //
+ // SYMTYPE is always notype for C/C++ symbols as there's no typeinfo and
+ // no way to get the symbol type from name (de)mangling. However, we
+ // care if "notype" is suffixed by "()" or not. The presence of () means
+ // the symbol is a function, the absence means it isn't.
+ //
+ // VISIBILITY indicates whether it's a compilation-unit local static
+ // symbol ("Static"), or whether it's available for use from other
+ // compilation units ("External"). Note that there are other values,
+ // such as "WeakExternal", and "Label".
+ //
+ // SYMNAME is the symbol name.
+ //
+ // The first symbol in each section appears to specify the section type,
+ // for example:
+ //
+ // 006 00000000 SECT3 notype Static | .rdata
+ // B44 00000000 SECT4 notype Static | .rdata$r
+ // AA2 00000000 SECT5 notype Static | .bss
+ //
+
+ // Map of read-only (.rdata, .xdata) and uninitialized (.bss) sections
+ // to their types (R and B, respectively). If a section is not found in
+ // this map, then it's assumed to be normal data (.data).
+ //
+ map<string, char> sections;
+
+ string l;
+ while (!eof (getline (is, l)))
+ {
+ size_t b (0), e (0), n;
+
+ // IDX (note that it can be more than 3 characters).
+ //
+ if (next_word (l, b, e) == 0)
+ continue;
+
+ // OFFSET (always 8 characters).
+ //
+ n = next_word (l, b, e);
+
+ if (n != 8)
+ continue;
+
+ string off (l, b, n);
+
+ // SECT
+ //
+ n = next_word (l, b, e);
+
+ if (n == 0 || l.compare (b, n, "UNDEF") == 0)
+ continue;
+
+ string sec (l, b, n);
+
+ // TYPE
+ //
+ n = next_word (l, b, e);
+
+ if (l.compare (b, n, "notype") != 0)
+ continue;
+
+ bool d;
+ if (l[e] == ' ' && l[e + 1] == '(' && l[e + 2] == ')')
+ {
+ e += 3;
+ d = false;
+ }
+ else
+ d = true;
+
+ // VISIBILITY
+ //
+ n = next_word (l, b, e);
+
+ if (n == 0)
+ continue;
+
+ string vis (l, b, n);
+
+ // |
+ //
+ n = next_word (l, b, e);
+
+ if (n != 1 || l[b] != '|')
+ continue;
+
+ // SYMNAME
+ //
+ n = next_word (l, b, e);
+
+ if (n == 0)
+ continue;
+
+ string s (l, b, n);
+
+ // See if this is the section type symbol.
+ //
+ if (d && off == "00000000" && vis == "Static" && s[0] == '.')
+ {
+ auto cmp = [&s] (const char* n, size_t l)
+ {
+ return s.compare (0, l, n) == 0 && (s[l] == '\0' || s[l] == '$');
+ };
+
+ if (cmp (".rdata", 6) ||
+ cmp (".xdata", 6)) sections.emplace (move (sec), 'R');
+ else if (cmp (".bss", 4)) sections.emplace (move (sec), 'B');
+
+ continue;
+ }
+
+ // We can only export extern symbols.
+ //
+ if (vis != "External")
+ continue;
+
+ if (d)
+ {
+ auto i (sections.find (sec));
+ switch (i == sections.end () ? 'D' : i->second)
+ {
+ case 'D': syms.d.insert (move (s)); break;
+ case 'R': syms.r.insert (move (s)); break;
+ case 'B': syms.b.insert (move (s)); break;
+ }
+ }
+ else
+ syms.t.insert (move (s));
+ }
+ }
+
+ static void
+ parse_llvm_nm (istream& is, symbols& syms)
+ {
+ // Lines that describe symbols look like:
+ //
+ // <NAME> <TYPE> <VALUE> <SIZE>
+ //
+ // The types that we are interested in are T, D, R, and B.
+ //
+ string l;
+ while (!eof (getline (is, l)))
+ {
+ size_t b (0), e (0), n;
+
+ // NAME
+ //
+ n = next_word (l, b, e);
+
+ if (n == 0)
+ continue;
+
+ string s (l, b, n);
+
+ // TYPE
+ //
+ n = next_word (l, b, e);
+
+ if (n != 1)
+ continue;
+
+ switch (l[b])
+ {
+ case 'D': syms.d.insert (move (s)); break;
+ case 'R': syms.r.insert (move (s)); break;
+ case 'B': syms.b.insert (move (s)); break;
+ case 'T': syms.t.insert (move (s)); break;
+ }
+ }
+ }
+
+ bool def_rule::
+ match (action a, target& t, const string&) const
+ {
+ tracer trace ("bin::def_rule::match");
+
+ // See if we have an object file or a utility library.
+ //
+ for (prerequisite_member p: reverse_group_prerequisite_members (a, t))
+ {
+ // If excluded or ad hoc, then don't factor it into our tests.
+ //
+ if (include (a, t, p) != include_type::normal)
+ continue;
+
+ if (p.is_a<obj> () || p.is_a<objs> () ||
+ p.is_a<bmi> () || p.is_a<bmis> () ||
+ p.is_a<libul> () || p.is_a<libus> ())
+ return true;
+ }
+
+ l4 ([&]{trace << "no object or utility library prerequisite for target "
+ << t;});
+ return false;
+ }
+
+ recipe def_rule::
+ apply (action a, target& xt) const
+ {
+ def& t (xt.as<def> ());
+
+ t.derive_path ();
+
+ // Inject dependency on the output directory.
+ //
+ inject_fsdir (a, t);
+
+ // Match prerequisites only picking object files and utility libraries.
+ //
+ match_prerequisite_members (
+ a,
+ t,
+ [] (action a,
+ const target& t,
+ const prerequisite_member& p,
+ include_type i) -> prerequisite_target
+ {
+ return
+ i == include_type::adhoc ? nullptr :
+ //
+ // If this is a target group, then pick the appropriate member
+ // (the same semantics as what we have in link-rule).
+ //
+ p.is_a<obj> () ? &search (t, objs::static_type, p.key ()) :
+ p.is_a<bmi> () ? &search (t, bmis::static_type, p.key ()) :
+ p.is_a<libul> () ? link_member (p.search (t).as<libul> (),
+ a,
+ linfo {otype::s, lorder::s}) :
+ p.is_a<objs> () ||
+ p.is_a<bmis> () ||
+ p.is_a<libus> () ? &p.search (t) : nullptr;
+ });
+
+ switch (a)
+ {
+ case perform_update_id: return &perform_update;
+ case perform_clean_id: return &perform_clean_depdb; // Standard clean.
+ default: return noop_recipe; // Configure update.
+ }
+ }
+
+ target_state def_rule::
+ perform_update (action a, const target& xt)
+ {
+ tracer trace ("bin::def_rule::perform_update");
+
+ const def& t (xt.as<def> ());
+ const path& tp (t.path ());
+
+ context& ctx (t.ctx);
+
+ const scope& bs (t.base_scope ());
+ const scope& rs (*bs.root_scope ());
+
+ // For link.exe we use its /DUMP option to access dunpbin.exe. For
+ // lld-link we use llvm-nm.
+ //
+ const string& lid (cast<string> (rs["bin.ld.id"]));
+
+ // Update prerequisites and determine if anything changed.
+ //
+ timestamp mt (t.load_mtime ());
+ optional<target_state> ts (execute_prerequisites (a, t, mt));
+
+ bool update (!ts);
+
+ // We use depdb to track changes to the input set, etc.
+ //
+ depdb dd (tp + ".d");
+
+ // First should come the rule name/version.
+ //
+ if (dd.expect (rule_id_) != nullptr)
+ l4 ([&]{trace << "rule mismatch forcing update of " << t;});
+
+ // Then the nm checksum.
+ //
+ if (dd.expect (lid == "msvc-lld"
+ ? cast<string> (rs["bin.nm.checksum"])
+ : cast<string> (rs["bin.ld.checksum"])) != nullptr)
+ l4 ([&]{trace << "linker mismatch forcing update of " << t;});
+
+ // @@ TODO: track in depdb if making symbol filtering configurable.
+
+ // Collect and hash the list of object files seeing through libus{}.
+ //
+ vector<reference_wrapper<const objs>> os;
+ {
+ sha256 cs;
+
+ auto collect = [a, &rs, &os, &cs] (const file& t,
+ const auto& collect) -> void
+ {
+ for (const target* pt: t.prerequisite_targets[a])
+ {
+ if (pt == nullptr)
+ continue;
+
+ const objs* o;
+ if ((o = pt->is_a<objs> ()) != nullptr)
+ ;
+ else if (pt->is_a<hbmi> ())
+ o = find_adhoc_member<objs> (*pt);
+ //
+ // Note that in prerequisite targets we will have the libux{}
+ // members, not the group.
+ //
+ else if (const libus* l = pt->is_a<libus> ())
+ {
+ collect (*l, collect);
+ continue;
+ }
+ else
+ continue;
+
+ hash_path (cs, o->path (), rs.out_path ());
+ os.push_back (*o);
+ }
+ };
+
+ collect (t, collect);
+
+ if (dd.expect (cs.string ()) != nullptr)
+ l4 ([&]{trace << "file set mismatch forcing update of " << t;});
+ }
+
+ // Update if any mismatch or depdb is newer that the output.
+ //
+ if (dd.writing () || dd.mtime > mt)
+ update = true;
+
+ dd.close ();
+
+ // If nothing changed, then we are done.
+ //
+ if (!update)
+ return *ts;
+
+ const process_path& nm (lid == "msvc-lld"
+ ? cast<process_path> (rs["bin.nm.path"])
+ : cast<process_path> (rs["bin.ld.path"]));
+
+ const string& cpu (cast<string> (rs["bin.target.cpu"]));
+ bool i386 (cpu.size () == 4 &&
+ cpu[0] == 'i' && cpu[2] == '8' && cpu[3] == '6');
+
+ cstrings args {nm.recall_string ()};
+
+ if (lid == "msvc-lld")
+ {
+ args.push_back ("--no-weak");
+ args.push_back ("--defined-only");
+ args.push_back ("--format=posix");
+ }
+ else
+ {
+ args.push_back ("/DUMP"); // Must come first.
+ args.push_back ("/NOLOGO");
+ args.push_back ("/SYMBOLS");
+ }
+
+ args.push_back (nullptr); // Argument placeholder.
+ args.push_back (nullptr);
+
+ const char*& arg (*(args.end () - 2));
+
+ if (verb == 1)
+ text << "gen " << t;
+
+ // Extract symbols from each object file.
+ //
+ symbols syms;
+ for (const objs& o: os)
+ {
+ // Use a relative path for nicer diagnostics.
+ //
+ path rp (relative (o.path ()));
+ arg = rp.string ().c_str ();
+
+ if (verb >= 2)
+ print_process (args);
+
+ if (ctx.dry_run)
+ continue;
+
+ // Both link.exe /DUMP and llvm-nm send their output to stdout. While
+ // llvm-nm sends diagnostics to stderr, link.exe sends it to stdout
+ // together with the output.
+ //
+ process pr (run_start (nm,
+ args,
+ 0 /* stdin */,
+ -1 /* stdout */));
+ bool io (false);
+ try
+ {
+ ifdstream is (
+ move (pr.in_ofd), fdstream_mode::skip, ifdstream::badbit);
+
+ if (lid == "msvc-lld")
+ parse_llvm_nm (is, syms);
+ else
+ parse_dumpbin (is, syms);
+
+ is.close ();
+ }
+ catch (const io_error&)
+ {
+ // Presumably the child process failed so let run_finish() deal with
+ // that first.
+ //
+ io = true;
+ }
+
+ if (!run_finish_code (args.data (), pr) || io)
+ fail << "unable to extract symbols from " << arg;
+ }
+
+ /*
+ for (const string& s: syms.d) text << "D " << s;
+ for (const string& s: syms.r) text << "R " << s;
+ for (const string& s: syms.b) text << "B " << s;
+ for (const string& s: syms.t) text << "T " << s;
+ */
+
+ if (verb >= 3)
+ text << "cat >" << tp;
+
+ if (!ctx.dry_run)
+ {
+ auto_rmfile rm (tp);
+
+ try
+ {
+ ofdstream os (tp);
+
+ os << "; Auto-generated, do not edit.\n"
+ << "EXPORTS\n";
+
+ // Our goal here is to export the same types of symbols as what gets
+ // exported with __declspec(dllexport) (which can be viewed with
+ // dumpbin /EXPORTS).
+ //
+ // Some special C++ symbol patterns:
+ //
+ // Data symbols:
+ //
+ // ??_C* -- string literal (R, not exported)
+ // ??_7* -- vtable (R, exported)
+ // ??_R* -- rtti, can be prefixed with _CT/__CT (D/R, not exported)
+ //
+ // Text symbols:
+ //
+ // ??_G* -- scalar deleting destructor (not exported)
+ // ??_E* -- vector deleting destructor (not exported)
+ //
+ // The following two symbols seem to be related to exception
+ // throwing and most likely should not be exported.
+ //
+ // R _CTA3?AVinvalid_argument@std@@
+ // R _TI3?AVinvalid_argument@std@@
+ //
+ // There are also what appears to be floating point literals:
+ //
+ // R __real@3f80000
+ //
+ // For some reason i386 object files have extern "C" symbols (both
+ // data and text) prefixed with an underscore which must be stripped
+ // in the .def file.
+ //
+ // Note that the extra prefix seems to be also added to special
+ // symbols so something like _CT??... becomes __CT??... on i386.
+ // However, for such symbols the underscore shall not be removed.
+ // Which means an extern "C" _CT becomes __CT on i383 and hard to
+ // distinguish from the special symbols. We deal with this by only
+ // stripping the underscore if the symbols doesn't contain any
+ // special characters (?@).
+ //
+ auto extern_c = [] (const string& s)
+ {
+ return s.find_first_of ("?@") == string::npos;
+ };
+
+ auto strip = [i386, &extern_c] (const string& s) -> const char*
+ {
+ const char* r (s.c_str ());
+
+ if (i386 && s[0] == '_' && extern_c (s))
+ r++;
+
+ return r;
+ };
+
+ for (const string& s: syms.t)
+ {
+ auto filter = [&strip] (const string& s) -> const char*
+ {
+ if (s.compare (0, 4, "??_G") == 0 ||
+ s.compare (0, 4, "??_E") == 0)
+ return nullptr;
+
+ return strip (s);
+ };
+
+ if (const char* v = filter (s))
+ os << " " << v << '\n';
+ }
+
+ // Note that it's not easy to import data without a dllimport
+ // declaration.
+ //
+ if (true)
+ {
+ auto filter = [&strip] (const string& s) -> const char*
+ {
+ if (s.compare (0, 4, "??_R") == 0 ||
+ s.compare (0, 4, "??_C") == 0)
+ return nullptr;
+
+ return strip (s);
+ };
+
+ for (const string& s: syms.d)
+ if (const char* v = filter (s))
+ os << " " << v << " DATA\n";
+
+ for (const string& s: syms.b)
+ if (const char* v = filter (s))
+ os << " " << v << " DATA\n";
+
+ // Read-only data contains an especially large number of various
+ // special symbols. Instead of trying to filter them out case by
+ // case, we will try to recognize C/C++ identifiers plus the
+ // special symbols that we need to export (e.g., vtable).
+ //
+ //
+ for (const string& s: syms.r)
+ {
+ if (extern_c (s) || // C
+ (s[0] == '?' && s[1] != '?') || // C++
+ s.compare (0, 4, "??_7") == 0) // vtable
+ {
+ os << " " << strip (s) << " DATA\n";
+ }
+ }
+ }
+
+ os.close ();
+ rm.cancel ();
+ }
+ catch (const io_error& e)
+ {
+ fail << "unable to write to " << tp << ": " << e;
+ }
+
+ dd.check_mtime (tp);
+ }
+
+ t.mtime (system_clock::now ());
+ return target_state::changed;
+ }
+
+ const string def_rule::rule_id_ {"bin.def 1"};
+ }
+}
generated by cgit v1.1 at 2024-11-01 09:27:31 +0000