Initial work on child process diagnostics buffering

Currently this is implemented for C/C++ compile and link rules.

3 files changed, 141 insertions, 81 deletions

diff --git a/libbuild2/cc/compile-rule.cxx b/libbuild2/cc/compile-rule.cxx
index fda97a0..8d507e7 100644
--- a/libbuild2/cc/compile-rule.cxx
+++ b/libbuild2/cc/compile-rule.cxx
@@ -264,6 +264,10 @@ namespace build2
     compile_rule::
     compile_rule (data&& d, const scope& rs)
         : common (move (d)),
+          //
+          // @@ TODO: split into rule_name (string) and rule_version (integer)
+          //    on next increment.
+          //
           rule_id (string (x) += ".compile 6")
     {
       // Locate the header cache (see enter_header() for details).
@@ -3961,6 +3965,8 @@ namespace build2
               // diagnostics (if things go badly we will restart with this
               // support).
               //
+              // @@ TODO: diag_buffer
+              //
               if (drmp == nullptr) // Dependency info goes to stdout.
               {
                 assert (!sense_diag); // Note: could support with fdselect().
@@ -3970,7 +3976,7 @@ namespace build2
                 //
                 pr = process (
                   cpath,
-                  args.data (),
+                  args,
                   0,
                   -1,
                   cclass == compiler_class::msvc ? 1 : gen ? 2 : -2,
@@ -3980,7 +3986,7 @@ namespace build2
               else // Dependency info goes to a temporary file.
               {
                 pr = process (cpath,
-                              args.data (),
+                              args,
                               mod_mapper ? -1 : 0,
                               mod_mapper ? -1 : 2, // Send stdout to stderr.
                               gen ? 2 : sense_diag ? -1 : -2,
@@ -4890,10 +4896,10 @@ namespace build2
               print_process (args);
 
             // We don't want to see warnings multiple times so ignore all
-            // diagnostics.
+            // diagnostics (thus no need for diag_buffer).
             //
             pr = process (cpath,
-                          args.data (),
+                          args,
                           0, -1, -2,
                           nullptr, // CWD
                           env.empty () ? nullptr : env.data ());
@@ -6327,7 +6333,7 @@ namespace build2
     // Filter cl.exe noise (msvc.cxx).
     //
     void
-    msvc_filter_cl (ifdstream&, const path& src);
+    msvc_filter_cl (diag_buffer&, const path& src);
 
     // Append header unit-related options.
     //
@@ -6674,7 +6680,7 @@ namespace build2
       small_vector<string, 2> module_args; // Module options storage.
 
       size_t out_i (0);  // Index of the -o option.
-      size_t lang_n (0); // Number of lang options.
+      //size_t lang_n (0); // Number of lang options. @@ TMP
 
       switch (cclass)
       {
@@ -7025,7 +7031,7 @@ namespace build2
             args.push_back ("-c");
           }
 
-          lang_n = append_lang_options (args, md);
+          /*lang_n = */append_lang_options (args, md); // @@ TMP
 
           if (md.pp == preprocessed::all)
           {
@@ -7074,6 +7080,8 @@ namespace build2
       // the source file, not its preprocessed version (so that it's easy to
       // copy and re-run, etc). Only at level 3 and above print the real deal.
       //
+      // @@ TODO: why don't we print env (here and/or below)? Also link rule.
+      //
       if (verb == 1)
         text << x_name << ' ' << s;
       else if (verb == 2)
@@ -7081,12 +7089,17 @@ namespace build2
 
       // If we have the (partially) preprocessed output, switch to that.
       //
+      // But we remember the original source/position to restore later.
+      //
       bool psrc (md.psrc);
       bool ptmp (psrc && md.psrc.temporary);
+      pair<size_t, const char*> osrc;
       if (psrc)
       {
         args.pop_back (); // nullptr
+        osrc.second = args.back ();
         args.pop_back (); // sp
+        osrc.first = args.size ();
 
         sp = &md.psrc.path ();
 
@@ -7096,6 +7109,8 @@ namespace build2
         {
         case compiler_type::gcc:
           {
+            // @@ TMP
+#if 0
             // The -fpreprocessed is implied by .i/.ii. But not when compiling
             // a header unit (there is no .hi/.hii).
             //
@@ -7109,6 +7124,15 @@ namespace build2
               //
               for (; lang_n != 0; --lang_n)
                 args.pop_back ();
+#else
+            // -fpreprocessed is implied by .i/.ii unless compiling a header
+            // unit (there is no .hi/.hii). Also, we would need to pop -x
+            // since it takes precedence over the extension, which would mess
+            // up our osrc logic. So in the end it feels like always passing
+            // explicit -fpreprocessed is the way to go.
+            //
+            args.push_back ("-fpreprocessed");
+#endif
 
             args.push_back ("-fdirectives-only");
             break;
@@ -7145,6 +7169,8 @@ namespace build2
       if (verb >= 3)
         print_process (args);
 
+      diag_buffer dbuf (ctx);
+
       // @@ DRYRUN: Currently we discard the (partially) preprocessed file on
       // dry-run which is a waste. Even if we keep the file around (like we do
       // for the error case; see above), we currently have no support for
@@ -7163,45 +7189,36 @@ namespace build2
           file_cache::read psrcr (psrc ? md.psrc.open () : file_cache::read ());
 
           // VC cl.exe sends diagnostics to stdout. It also prints the file
-          // name being compiled as the first line. So for cl.exe we redirect
-          // stdout to a pipe, filter that noise out, and send the rest to
-          // stderr.
+          // name being compiled as the first line. So for cl.exe we filter
+          // that noise out.
           //
-          // For other compilers redirect stdout to stderr, in case any of
-          // them tries to pull off something similar. For sane compilers this
-          // should be harmless.
+          // For other compilers also redirect stdout to stderr, in case any
+          // of them tries to pull off something similar. For sane compilers
+          // this should be harmless.
           //
           bool filter (ctype == compiler_type::msvc);
 
           process pr (cpath,
-                      args.data (),
-                      0, (filter ? -1 : 2), 2,
+                      args,
+                      0, 2, dbuf.open (args[0], filter),
                       nullptr, // CWD
                       env.empty () ? nullptr : env.data ());
 
           if (filter)
-          {
-            try
-            {
-              ifdstream is (
-                move (pr.in_ofd), fdstream_mode::text, ifdstream::badbit);
-
-              msvc_filter_cl (is, *sp);
+            msvc_filter_cl (dbuf, *sp);
 
-              // If anything remains in the stream, send it all to stderr.
-              // Note that the eof check is important: if the stream is at
-              // eof, this and all subsequent writes to the diagnostics stream
-              // will fail (and you won't see a thing).
-              //
-              if (is.peek () != ifdstream::traits_type::eof ())
-                diag_stream_lock () << is.rdbuf ();
+          dbuf.read ();
 
-              is.close ();
-            }
-            catch (const io_error&) {} // Assume exits with error.
+          // Restore the original source if we switched to preprocessed.
+          //
+          if (psrc)
+          {
+            args.resize (osrc.first);
+            args.push_back (osrc.second);
+            args.push_back (nullptr);
           }
 
-          run_finish (args, pr);
+          dbuf.finish (args, pr);
         }
         catch (const process_error& e)
         {
@@ -7252,12 +7269,14 @@ namespace build2
           try
           {
             process pr (cpath,
-                        args.data (),
-                        0, 2, 2,
+                        args,
+                        0, 2, dbuf.open (args[0]),
                         nullptr, // CWD
                         env.empty () ? nullptr : env.data ());
 
-            run_finish (args, pr);
+            dbuf.read ();
+
+            dbuf.finish (args, pr);
           }
           catch (const process_error& e)
           {
diff --git a/libbuild2/cc/link-rule.cxx b/libbuild2/cc/link-rule.cxx
index a5fa7bc..5d212e6 100644
--- a/libbuild2/cc/link-rule.cxx
+++ b/libbuild2/cc/link-rule.cxx
@@ -254,6 +254,10 @@ namespace build2
     link_rule::
     link_rule (data&& d)
         : common (move (d)),
+          //
+          // @@ TODO: split into rule_name (string) and rule_version (integer)
+          //    on next increment.
+          //
           rule_id (string (x) += ".link 3")
     {
     }
@@ -2671,7 +2675,7 @@ namespace build2
     // Filter link.exe noise (msvc.cxx).
     //
     void
-    msvc_filter_link (ifdstream&, const file&, otype);
+    msvc_filter_link (diag_buffer&, const file&, otype);
 
     // Translate target CPU to the link.exe/lib.exe /MACHINE option.
     //
@@ -2879,6 +2883,8 @@ namespace build2
         env_ptrs.push_back (nullptr);
       }
 
+      diag_buffer dbuf (ctx);
+
       // If targeting Windows, take care of the manifest.
       //
       path manifest; // Manifest itself (msvc) or compiled object file.
@@ -2929,12 +2935,15 @@ namespace build2
 
               try
               {
+                // We assume that what we write to stdin is small enough to
+                // fit into the pipe's buffer without blocking.
+                //
                 process pr (rc,
                             args,
-                            -1      /* stdin  */,
-                            1       /* stdout */,
-                            2       /* stderr */,
-                            nullptr /* cwd    */,
+                            -1                  /* stdin  */,
+                            1                   /* stdout */,
+                            dbuf.open (args[0]) /* stderr */,
+                            nullptr             /* cwd    */,
                             env_ptrs.empty () ? nullptr : env_ptrs.data ());
 
                 try
@@ -2960,7 +2969,8 @@ namespace build2
                   // was caused by that and let run_finish() deal with it.
                 }
 
-                run_finish (args, pr);
+                dbuf.read ();
+                dbuf.finish (args, pr, 2 /* verbosity */);
               }
               catch (const process_error& e)
               {
@@ -3823,8 +3833,21 @@ namespace build2
       else if (verb == 2)
         print_process (args);
 
+      // Do any necessary fixups to the command line to make it runnable.
+      //
+      // Notice the split in the diagnostics: at verbosity level 1 we print
+      // the "logical" command line while at level 2 and above -- what we are
+      // actually executing.
+      //
+      // We also need to save the original for the diag_buffer::close() call
+      // below if at verbosity level 1.
+      //
+      cstrings oargs;
+
       // Adjust linker parallelism.
       //
+      // Note that we are not going to bother with oargs for this.
+      //
       string jobs_arg;
       scheduler::alloc_guard jobs_extra;
 
@@ -3875,12 +3898,6 @@ namespace build2
         }
       }
 
-      // Do any necessary fixups to the command line to make it runnable.
-      //
-      // Notice the split in the diagnostics: at verbosity level 1 we print
-      // the "logical" command line while at level 2 and above -- what we are
-      // actually executing.
-      //
       // On Windows we need to deal with the command line length limit. The
       // best workaround seems to be passing (part of) the command line in an
       // "options file" ("response file" in Microsoft's terminology). Both
@@ -3966,14 +3983,15 @@ namespace build2
             fail << "unable to write to " << f << ": " << e;
           }
 
+          if (verb == 1)
+            oargs = args;
+
           // Replace input arguments with @file.
           //
           targ = '@' + f.string ();
           args.resize (args_input);
           args.push_back (targ.c_str());
           args.push_back (nullptr);
-
-          //@@ TODO: leave .t file if linker failed and verb > 2?
         }
       }
 #endif
@@ -3996,51 +4014,48 @@ namespace build2
         {
           // VC tools (both lib.exe and link.exe) send diagnostics to stdout.
           // Also, link.exe likes to print various gratuitous messages. So for
-          // link.exe we redirect stdout to a pipe, filter that noise out, and
-          // send the rest to stderr.
+          // link.exe we filter that noise out.
           //
           // For lib.exe (and any other insane linker that may try to pull off
           // something like this) we are going to redirect stdout to stderr.
           // For sane compilers this should be harmless.
           //
           // Note that we don't need this for LLD's link.exe replacement which
-          // is quiet.
+          // is thankfully quiet.
           //
           bool filter (tsys == "win32-msvc"  &&
                        !lt.static_library () &&
                        cast<string> (rs["bin.ld.id"]) != "msvc-lld");
 
           process pr (*ld,
-                      args.data (),
-                      0                  /* stdin  */,
-                      (filter ? -1 : 2)  /* stdout */,
-                      2                  /* stderr */,
-                      nullptr            /* cwd    */,
+                      args,
+                      0                           /* stdin  */,
+                      2                           /* stdout */,
+                      dbuf.open (args[0], filter) /* stderr */,
+                      nullptr                     /* cwd    */,
                       env_ptrs.empty () ? nullptr : env_ptrs.data ());
 
           if (filter)
+            msvc_filter_link (dbuf, t, ot);
+
+          dbuf.read ();
+
           {
-            try
-            {
-              ifdstream is (
-                move (pr.in_ofd), fdstream_mode::text, ifdstream::badbit);
+            bool e (pr.wait ());
 
-              msvc_filter_link (is, t, ot);
+#ifdef _WIN32
+            // Keep the options file if we have shown it.
+            //
+            if (!e && verb > 2)
+              trm.cancel ();
+#endif
 
-              // If anything remains in the stream, send it all to stderr.
-              // Note that the eof check is important: if the stream is at
-              // eof, this and all subsequent writes to the diagnostics stream
-              // will fail (and you won't see a thing).
-              //
-              if (is.peek () != ifdstream::traits_type::eof ())
-                diag_stream_lock () << is.rdbuf ();
+            dbuf.close (oargs.empty () ? args : oargs, *pr.exit);
 
-              is.close ();
-            }
-            catch (const io_error&) {} // Assume exits with error.
+            if (!e)
+              throw failed ();
           }
 
-          run_finish (args, pr);
           jobs_extra.deallocate ();
         }
         catch (const process_error& e)
@@ -4100,10 +4115,25 @@ namespace build2
           print_process (args);
 
         if (!ctx.dry_run)
+        {
+#if 0
           run (rl,
                args,
                dir_path () /* cwd */,
                env_ptrs.empty () ? nullptr : env_ptrs.data ());
+#else
+          process pr (rl,
+                      args,
+                      0                   /* stdin  */,
+                      1                   /* stdout */,
+                      dbuf.open (args[0]) /* stderr */,
+                      nullptr             /* cwd    */,
+                      env_ptrs.empty () ? nullptr : env_ptrs.data ());
+
+          dbuf.read ();
+          dbuf.finish (args, pr);
+#endif
+        }
       }
 
       // For Windows generate (or clean up) rpath-emulating assembly.
diff --git a/libbuild2/cc/msvc.cxx b/libbuild2/cc/msvc.cxx
index f95cab0..9aff347 100644
--- a/libbuild2/cc/msvc.cxx
+++ b/libbuild2/cc/msvc.cxx
@@ -164,18 +164,21 @@ namespace build2
 
     // Filter cl.exe and link.exe noise.
     //
+    // Note: must be followed with the dbuf.read() call.
+    //
     void
-    msvc_filter_cl (ifdstream& is, const path& src)
+    msvc_filter_cl (diag_buffer& dbuf, const path& src)
+    try
     {
       // While it appears VC always prints the source name (event if the
       // file does not exist), let's do a sanity check. Also handle the
       // command line errors/warnings which come before the file name.
       //
-      for (string l; !eof (getline (is, l)); )
+      for (string l; !eof (getline (dbuf.is, l)); )
       {
         if (l != src.leaf ().string ())
         {
-          diag_stream_lock () << l << endl;
+          dbuf.write (l, true /* newline */);
 
           if (msvc_sense_diag (l, 'D').first != string::npos)
             continue;
@@ -184,14 +187,19 @@ namespace build2
         break;
       }
     }
+    catch (const io_error&)
+    {
+      // Let the following diag_buffer::read() call deal with this.
+    }
 
     void
-    msvc_filter_link (ifdstream& is, const file& t, otype lt)
+    msvc_filter_link (diag_buffer& dbuf, const file& t, otype lt)
+    try
     {
       // Filter lines until we encounter something we don't recognize. We also
       // have to assume the messages can be translated.
       //
-      for (string l; getline (is, l); )
+      for (string l; getline (dbuf.is, l); )
       {
         // "   Creating library foo\foo.dll.lib and object foo\foo.dll.exp"
         //
@@ -216,12 +224,15 @@ namespace build2
 
         // /INCREMENTAL causes linker to sometimes issue messages but now I
         // can't quite reproduce it.
-        //
 
-        diag_stream_lock () << l << endl;
+        dbuf.write (l, true /* newline */);
         break;
       }
     }
+    catch (const io_error&)
+    {
+      // Let the following diag_buffer::read() call deal with this.
+    }
 
     void
     msvc_extract_header_search_dirs (const strings& v, dir_paths& r)