From d00a96c846dc7bad686d174aa27ad7d66da149da Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Thu, 2 Dec 2021 21:35:45 +0100
Subject: Add support for bootstrapping with custom compiler, including check
 for c++20 support.

---
 bootstrap.sh     | 13 ++++++++++---
 src/bootstrap.cc | 12 ++++++++++++
 src/configure.cc | 33 ++++++++++++++++-----------------
 3 files changed, 38 insertions(+), 20 deletions(-)

diff --git a/bootstrap.sh b/bootstrap.sh
index a5c11ac..510320a 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -1,7 +1,14 @@
 #!/bin/sh
 echo "Bootstrapping..."
-g++ -std=c++20 -Wall -O3 -Isrc -pthread src/bootstrap.cc ctor.cc test/ctor.cc -o ctor && \
-./ctor && \
-g++ -std=c++20 -Wall -O3 -Isrc -pthread ctor.cc test/ctor.cc -Lbuild -lctor -o ctor && \
+: ${CXX:=g++}
+$CXX -std=c++20 /dev/null -c -o /dev/null 2> /dev/null 1> /dev/null
+if [ $? != 0 ]
+then
+	echo "Set CXX to a compiler supporting c++20."
+	exit 1
+fi
+$CXX -std=c++20 -Wall -O3 -Isrc -pthread src/bootstrap.cc ctor.cc -o ctor && \
+CXX=`which $CXX` ./ctor && \
+$CXX -std=c++20 -Wall -O3 -Isrc -pthread ctor.cc test/ctor.cc -Lbuild -lctor -o ctor && \
 ./ctor configure --ctor-includedir=src --ctor-libdir=build && \
 echo "Done. Now run ./ctor to (re)build."
diff --git a/src/bootstrap.cc b/src/bootstrap.cc
index 08f7b1f..bf597ea 100644
--- a/src/bootstrap.cc
+++ b/src/bootstrap.cc
@@ -3,6 +3,7 @@
 // See accompanying file LICENSE for details.
 #include <iostream>
 #include <array>
+#include <cstdlib>
 
 #define BOOTSTRAP
 
@@ -29,12 +30,23 @@ const Configuration& configuration()
 
 bool hasConfiguration(const std::string& key)
 {
+	if(key == cfg::host_cxx && std::getenv("CXX"))
+	{
+		return true;
+	}
+
 	return false;
 }
 
 const std::string& getConfiguration(const std::string& key,
                                     const std::string& defaultValue)
 {
+	if(key == cfg::host_cxx && std::getenv("CXX"))
+	{
+		static std::string s = std::getenv("CXX");
+		return s;
+	}
+
 	return defaultValue;
 }
 
diff --git a/src/configure.cc b/src/configure.cc
index 37bd3cf..60c3ed6 100644
--- a/src/configure.cc
+++ b/src/configure.cc
@@ -27,18 +27,12 @@ const Configuration& __attribute__((weak)) configuration()
 
 namespace ctor
 {
-std::optional<std::string> includedir;
-std::optional<std::string> libdir;
+std::map<std::string, std::string> conf_values;
 }
 
 bool hasConfiguration(const std::string& key)
 {
-	if(key == cfg::ctor_includedir && ctor::includedir)
-	{
-		return true;
-	}
-
-	if(key == cfg::ctor_libdir && ctor::libdir)
+	if(ctor::conf_values.find(key) != ctor::conf_values.end())
 	{
 		return true;
 	}
@@ -50,14 +44,9 @@ bool hasConfiguration(const std::string& key)
 const std::string& getConfiguration(const std::string& key,
                                     const std::string& defaultValue)
 {
-	if(key == cfg::ctor_includedir && ctor::includedir)
-	{
-		return *ctor::includedir;
-	}
-
-	if(key == cfg::ctor_libdir && ctor::libdir)
+	if(ctor::conf_values.find(key) != ctor::conf_values.end())
 	{
-		return *ctor::libdir;
+		return ctor::conf_values[key];
 	}
 
 	const auto& c = configuration();
@@ -335,6 +324,18 @@ int regenerateCache(const Settings& default_settings,
 		                       newExternalConfigs.end());
 	}
 
+	// Store current values for execution in this execution context.
+	if(!ctor_includedir.empty())
+	{
+		ctor::conf_values[cfg::ctor_includedir] = ctor_includedir;
+	}
+	if(!ctor_libdir.empty())
+	{
+		ctor::conf_values[cfg::ctor_libdir] = ctor_libdir;
+	}
+	ctor::conf_values[cfg::host_cxx] = host_cxx;
+	ctor::conf_values[cfg::build_cxx] = build_cxx;
+
 	std::cout << "Writing results to: " << configurationFile.string() << "\n";
 	{
 		std::ofstream istr(configurationFile);
@@ -369,12 +370,10 @@ int regenerateCache(const Settings& default_settings,
 		if(!ctor_includedir.empty())
 		{
 			istr << "			{ \"" << cfg::ctor_includedir << "\", \"" << ctor_includedir << "\" },\n";
-			ctor::includedir = ctor_includedir;
 		}
 		if(!ctor_libdir.empty())
 		{
 			istr << "			{ \"" << cfg::ctor_libdir << "\", \"" << ctor_libdir << "\" },\n";
-			ctor::libdir = ctor_libdir;
 		}
 
 		istr << "		},\n";
-- 
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