Register environment variables for hermetic build configurations

3 files changed, 69 insertions, 4 deletions

diff --git a/libbuild2/bin/guess.cxx b/libbuild2/bin/guess.cxx
index 9f15030..219b8e8 100644
--- a/libbuild2/bin/guess.cxx
+++ b/libbuild2/bin/guess.cxx
@@ -326,6 +326,9 @@ namespace build2
           fail << "unable to guess " << *rl << " signature";
       }
 
+      // None of the ar/ranlib implementations we recognize seem to use
+      // environment variables (not even Microsoft lib.exe).
+      //
       return ar_cache.insert (move (key),
                               ar_info {
                                 move (arp),
@@ -333,13 +336,39 @@ namespace build2
                                 move (arr.signature),
                                 move (arr.checksum),
                                 move (*arr.version),
+                                nullptr,
 
                                 move (rlp),
                                 move (rlr.id),
                                 move (rlr.signature),
-                                move (rlr.checksum)});
+                                move (rlr.checksum),
+                                nullptr});
     }
 
+    // Linker environment variables (see also the cc module which duplicates
+    // some of these).
+    //
+    // Notes:
+    //
+    //  - GNU linkers search in LD_LIBRARY_PATH in addition to LD_RUN_PATH but
+    //    we assume the former is part of the built-in list. Interestingly,
+    //    LLD does not search in either.
+    //
+    //  - The LLD family of linkers have a bunch of undocumented, debugging-
+    //    related variables (LLD_REPRODUCE, LLD_VERSION, LLD_IN_TEST) that we
+    //    ignore.
+    //
+    //  - ld64 uses a ton of environment variables (according to the source
+    //    code) but none of them are documented in the man pages. So someone
+    //    will need to figure out what's important (some of them are clearly
+    //    for debugging of ld itself).
+    //
+    static const char* gnu_ld_env[] = {
+      "LD_RUN_PATH", "GNUTARGET", "LDEMULATION", "COLLECT_NO_DEMANGLE", nullptr};
+
+    static const char* msvc_ld_env[] = {
+      "LIB", "LINK", "_LINK_", nullptr};
+
     // Extracting ld information requires running it which can become
     // expensive if done repeatedly. So we cache the result.
     //
@@ -522,15 +551,26 @@ namespace build2
       if (r.empty ())
         fail << "unable to guess " << ld << " signature";
 
+      const char* const* ld_env ((r.id == "gnu"    ||
+                                  r.id == "gnu-gold") ? gnu_ld_env :
+                                 (r.id == "msvc"   ||
+                                  r.id == "msvc-lld") ? msvc_ld_env :
+                                 nullptr);
+
       return ld_cache.insert (move (key),
                               ld_info {
                                 move (pp),
                                 move (r.id),
                                 move (r.signature),
                                 move (r.checksum),
-                                move (r.version)});
+                                move (r.version),
+                                ld_env});
     }
 
+    // Resource compiler environment variables.
+    //
+    static const char* msvc_rc_env[] = {"INCLUDE", nullptr};
+
     // Extracting rc information requires running it which can become
     // expensive if done repeatedly. So we cache the result.
     //
@@ -632,12 +672,17 @@ namespace build2
       if (r.empty ())
         fail << "unable to guess " << rc << " signature";
 
+      const char* const* rc_env ((r.id == "msvc"   ||
+                                  r.id == "msvc-llvm") ? msvc_rc_env :
+                                 nullptr);
+
       return rc_cache.insert (move (key),
                               rc_info {
                                 move (pp),
                                 move (r.id),
                                 move (r.signature),
-                                move (r.checksum)});
+                                move (r.checksum),
+                                rc_env});
     }
   }
 }
diff --git a/libbuild2/bin/guess.hxx b/libbuild2/bin/guess.hxx
index 9a63fa1..e5da263 100644
--- a/libbuild2/bin/guess.hxx
+++ b/libbuild2/bin/guess.hxx
@@ -28,6 +28,9 @@ namespace build2
     // a toolchain-specific manner (usually the output of --version/-V) and
     // is not bulletproof.
     //
+    // The environment is an optional list of environment variables that
+    // affect ar/ranlib result.
+    //
     struct ar_info
     {
       process_path ar_path;
@@ -35,11 +38,13 @@ namespace build2
       string ar_signature;
       string ar_checksum;
       semantic_version ar_version;
+      const char* const* ar_environment;
 
       process_path ranlib_path;
       string ranlib_id;
       string ranlib_signature;
       string ranlib_checksum;
+      const char* const* ranlib_environment;
     };
 
     // The ranlib path can be NULL, in which case no ranlib guessing will be
@@ -72,6 +77,9 @@ namespace build2
     // toolchain-specific manner (usually the output of --version/-version/-v)
     // and is not bulletproof.
     //
+    // The environment is an optional list of environment variables that
+    // affect the linker result.
+    //
     // Note that for now the version is extracted only for some linkers. Once
     // it's done for all of them, we should drop optional.
     //
@@ -81,8 +89,8 @@ namespace build2
       string id;
       string signature;
       string checksum;
-
       optional<semantic_version> version;
+      const char* const* environment;
     };
 
     const ld_info&
@@ -102,12 +110,16 @@ namespace build2
     // toolchain-specific manner (usually the output of --version) and is not
     // bulletproof.
     //
+    // The environment is an optional list of environment variables that
+    // affect the resource compiler result.
+    //
     struct rc_info
     {
       process_path path;
       string id;
       string signature;
       string checksum;
+      const char* const* environment;
     };
 
     const rc_info&
diff --git a/libbuild2/bin/init.cxx b/libbuild2/bin/init.cxx
index 51066cb..62c7bcf 100644
--- a/libbuild2/bin/init.cxx
+++ b/libbuild2/bin/init.cxx
@@ -740,6 +740,8 @@ namespace build2
           rs.assign<string>   ("bin.ar.version.build") = v.build;
         }
 
+        config::save_environment (rs, ari.ar_environment);
+
         if (ranlib != nullptr)
         {
           rs.assign<process_path_ex> ("bin.ranlib.path")   =
@@ -747,6 +749,8 @@ namespace build2
           rs.assign<string>       ("bin.ranlib.id")        = ari.ranlib_id;
           rs.assign<string>       ("bin.ranlib.signature") = ari.ranlib_signature;
           rs.assign<string>       ("bin.ranlib.checksum")  = ari.ranlib_checksum;
+
+          config::save_environment (rs, ari.ranlib_environment);
         }
       }
 
@@ -871,6 +875,8 @@ namespace build2
           rs.assign<uint64_t> ("bin.ld.version.patch") = v.patch;
           rs.assign<string>   ("bin.ld.version.build") = v.build;
         }
+
+        config::save_environment (rs, ldi.environment);
       }
 
       return true;
@@ -995,6 +1001,8 @@ namespace build2
         rs.assign<string>       ("bin.rc.id")        = rci.id;
         rs.assign<string>       ("bin.rc.signature") = rci.signature;
         rs.assign<string>       ("bin.rc.checksum")  = rci.checksum;
+
+        config::save_environment (rs, rci.environment);
       }
 
       return true;