From 74dddb20753ad9f4addc54597674041d5fc40412 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 3 Dec 2017 13:08:24 +0200
Subject: [PATCH] Also get the linker system path from the actual linker
 program

---
 source/gnulinker.cpp | 97 +++++++++++++++++++++++++++++++++++++-------
 source/gnulinker.h   |  3 ++
 2 files changed, 86 insertions(+), 14 deletions(-)

diff --git a/source/gnulinker.cpp b/source/gnulinker.cpp
index a93f809..adc3efc 100644
--- a/source/gnulinker.cpp
+++ b/source/gnulinker.cpp
@@ -30,21 +30,7 @@ GnuLinker::GnuLinker(Builder &b, const Architecture &a, const FS::Path &sysroot)
 	processing_unit = COMPONENT;
 
 	if(!sysroot.empty())
-	{
 		build_info.sysroot = sysroot;
-		system_path.push_back(sysroot/"usr"/"lib");
-	}
-	else if(architecture->is_native())
-	{
-		system_path.push_back("/lib");
-		system_path.push_back("/usr/lib");
-		if(architecture->match_name("pc-32-linux"))
-			system_path.push_back("/usr/lib/i386-linux-gnu");
-		else if(architecture->match_name("pc-64-linux"))
-			system_path.push_back("/usr/lib/x86_64-linux-gnu");
-	}
-	else
-		system_path.push_back("/usr/"+architecture->get_cross_prefix()+"/lib");
 
 	default_linker = new Linker(*this, "CC");
 	cxx_linker = new Linker(*this, "CXX");
@@ -113,6 +99,89 @@ Target *GnuLinker::create_install(Target &target) const
 		return 0;
 }
 
+void GnuLinker::do_prepare()
+{
+	bool path_found = false;
+	const FS::Path &sysroot = build_info.sysroot;
+
+	Tool &compiler = builder.get_toolchain().get_tool("CC");
+	if(dynamic_cast<GnuCompiler *>(&compiler))
+	{
+		compiler.prepare();
+		FileTarget *compiler_exe = compiler.get_executable();
+		if(compiler_exe)
+		{
+			ExternalTask::Arguments argv;
+			argv.push_back(compiler_exe->get_path().str());
+			argv.push_back("-Wl,--verbose");
+			argv.push_back("-nostdlib");
+			if(!sysroot.empty())
+				argv.push_back("--sysroot="+sysroot.str());
+
+			builder.get_logger().log("auxcommands", format("Running %s", join(argv.begin(), argv.end())));
+			try
+			{
+				string output = ExternalTask::run_and_capture_output(argv, FS::Path(), true);
+				string::size_type start = 0;
+				while(start<output.size())
+				{
+					string::size_type search_dir = output.find("SEARCH_DIR(\"", start);
+					if(search_dir==string::npos)
+						break;
+
+					search_dir += 12;
+					string::size_type end = output.find("\");", search_dir);
+					if(end==string::npos)
+						break;
+
+					FS::Path path;
+					if(!output.compare(search_dir, 2, "=/"))
+					{
+						search_dir += 2;
+						if(sysroot.empty())
+							path = "/";
+						else
+							path = sysroot;
+					}
+
+					path /= output.substr(search_dir, end-search_dir);
+					builder.get_logger().log("tools", format("Got %s system path: %s", tag, path));
+					system_path.push_back(path);
+					path_found = true;
+
+					start = end+3;
+				}
+			}
+			catch(...)
+			{ }
+		}
+	}
+
+	if(!path_found)
+	{
+		builder.get_logger().log("tools", format("No %s system path found, using defaults", tag));
+		if(!sysroot.empty())
+			system_path.push_back(sysroot/"usr/lib");
+		else if(architecture->is_native())
+		{
+			system_path.push_back("/lib");
+			system_path.push_back("/usr/lib");
+			if(architecture->match_name("pc-32-linux"))
+			{
+				system_path.push_back("/lib/i386-linux-gnu");
+				system_path.push_back("/usr/lib/i386-linux-gnu");
+			}
+			else if(architecture->match_name("pc-64-linux"))
+			{
+				system_path.push_back("/lib/x86_64-linux-gnu");
+				system_path.push_back("/usr/lib/x86_64-linux-gnu");
+			}
+		}
+		else
+			system_path.push_back("/usr/"+architecture->get_cross_prefix()+"/lib");
+	}
+}
+
 Task *GnuLinker::run(const Target &) const
 {
 	throw logic_error("GnuLinker should not be run directly");
diff --git a/source/gnulinker.h b/source/gnulinker.h
index 872234a..7841700 100644
--- a/source/gnulinker.h
+++ b/source/gnulinker.h
@@ -37,6 +37,9 @@ public:
 
 	virtual Target *create_target(const std::list<Target *> &, const std::string &);
 	virtual Target *create_install(Target &) const;
+protected:
+	virtual void do_prepare();
+public:
 	virtual Task *run(const Target &) const;
 };
 
-- 
2.43.0