{"id":2229017,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2229017/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/20260427161804.1717021-1-dmalcolm@redhat.com/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/1.1/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20260427161804.1717021-1-dmalcolm@redhat.com>","date":"2026-04-27T16:18:04","name":"[pushed] wwwdocs: Document my gcc 16 changes","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"9cb62abd2c749fda5bddc7c37ca752fb405d3525","submitter":{"id":24465,"url":"http://patchwork.ozlabs.org/api/1.1/people/24465/?format=json","name":"David Malcolm","email":"dmalcolm@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/20260427161804.1717021-1-dmalcolm@redhat.com/mbox/","series":[{"id":501686,"url":"http://patchwork.ozlabs.org/api/1.1/series/501686/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=501686","date":"2026-04-27T16:18:04","name":"[pushed] wwwdocs: Document my gcc 16 changes","version":1,"mbox":"http://patchwork.ozlabs.org/series/501686/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2229017/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2229017/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","gcc-patches@gcc.gnu.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","gcc-patches@gcc.gnu.org"],"Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=fZzVL1Pp;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; 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charset=UTF-8","Content-Transfer-Encoding":"8bit","X-BeenThere":"gcc-patches@gcc.gnu.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Gcc-patches mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"},"content":"I've pushed this patch for the website to cover my various\nGCC 16 changes (and porting notes).\n\nDave\n\n---\n htdocs/gcc-16/changes.html | 265 +++++++++++++++++++++++++++++++++-\n htdocs/gcc-16/porting_to.html | 183 +++++++++++++++++++++++\n 2 files changed, 447 insertions(+), 1 deletion(-)","diff":"diff --git a/htdocs/gcc-16/changes.html b/htdocs/gcc-16/changes.html\nindex c56f3b8b..65462545 100644\n--- a/htdocs/gcc-16/changes.html\n+++ b/htdocs/gcc-16/changes.html\n@@ -36,6 +36,12 @@ a work-in-progress.

\n predefines _REENTRANT on Solaris.\n See the porting notes for more\n information.\n+
  • The so-called \"json\" format for\n+ -fdiagnostics-format=\n+ has been removed in this release.\n+ Users seeking machine-readable diagnostics from GCC should use\n+ SARIF.\n+
    • \n \n \n \n@@ -265,6 +271,21 @@ for general information.

    \n of diagnostic text (PR102613)\n \n \n+
  • Various C++ error messages (such as for problems involving templates)\n+ now have a hierarchical structure. This nesting of messages is presented\n+ using indentation and bullet points. The old behavior can be restored via\n+ -fno-diagnostics-show-nesting\n+ or\n+ -fdiagnostics-plain-output.\n+ \n+ \n+ \n+ \n+
    • \n \n \n

    Runtime Library (libstdc++)

    \n@@ -632,7 +653,249 @@ struct Affected : E\n \n \n \n-\n+

    Improvements to GCC Diagnostics

    \n+
      \n+
    • GCC can now output diagnostics in HTML form via\n+ -fdiagnostics-add-output=experimental-html\n+
      • \n+\n+
    • GCC's SARIF output now respects the\n+ dump directory.\n+ For example, given\n+ 
      \n+      gcc \\\n+        -o build-dir/foo.o \\\n+        -fdiagnostics-add-output=sarif\n+        foo.c\n+
      \n+ GCC 15 would write the SARIF to foo.c.sarif, whereas\n+ GCC 16 now writes it to build-dir/foo.c.sarif.\n+ \n+
      • \n+\n+\n+
    • GCC's SARIF output now captures the nesting of logical locations.\n+ \n+
      • \n+\n+
    • In GCC's SARIF output,\n+ fix objects now contain\n+ description properties in many cases.\n+ \n+
      • \n+\n+
    • GCC's SARIF output has gained 5 new values for the\n+ §3.38.8 kinds property of threadFlowLocation,\n+ for expressing non-standard control flow:\n+
        \n+
      • throw for throwing an exception
        • \n+
      • catch for catching an exception
        • \n+
      • unwind for unwinding stack frame(s) during\n+\texception-handling
        • \n+
      • setjmp for calls to setjmp
        • \n+
      • longjmp for calls to longjmp that rewind the\n+\tprogram counter/stack to the location of a previous setjmp call
        • \n+
      \n+ \n+
      • \n+\n+
    • GCC diagnostics can now have directed graphs associated with them, and\n+ can also report \"global\" directed graphs. Graphs are ignored by text sinks,\n+ but are captured by SARIF sinks, and the \"experimental-html\" renders any\n+ such graphs in SVG-based form using dot. For example, setting\n+ cfgs=yes on a SARIF or HTML diagnostic sink will enable\n+ capturing GCC's intermediate representation of every function at every\n+ optimization pass.
      • \n+\n+
    • GCC diagnostics can now refer to logical locations inside XML and JSON\n+ files (such as via libgdiagnostics). The sarif-replay tool\n+ now uses this to provide JSON pointers when it reports on issues in its\n+ SARIF input.
      • \n+\n+
    • If\n+ GCC_DIAGNOSTICS_LOG\n+ is set in the environment, GCC's diagnostic subsystem will emit a\n+ text log to stderr (or a named file) to track what it's doing and the\n+ decisions it's making (e.g. exactly when and why a diagnostic is being\n+ rejected).
      • \n+\n+
    • If\n+ EXPERIMENTAL_SARIF_SOCKET\n+ is set in the environment, GCC will attempt to connect to that socket on\n+ startup and send JSON-RPC notifications to it for every diagnostic emitted.\n+ \n+
      • \n+
    \n+\n+\n+

    Improvements for plugin authors

    \n+
      \n+
    • GCC has gained a \"publish/subscribe\" framework, allowing for\n+ loosely-coupled senders and receivers, with strongly-typed messages\n+ passing between them. In this release the only topics for plugins\n+ to subscribe to are:\n+
        \n+
      • events relating to optimization passes starting/stopping on particular\n+\tfunctions\n+ \n+
        • \n+
      • events relating to the static analyzer\n+ \n+
        • \n+
      \n+
      • \n+\n+
    • GCC diagnostic sinks can now have extension objects\n+ associated with them, with a finalizer hook. Plugins can\n+ use this to capture additional information in SARIF output files.\n+ \n+
      • \n+\n+
    • GCC's diagnostic machinery has been substantially cleaned up in GCC 16.\n+ This should not affect plugins that use just the\n+ diagnostic-core.h header, but maintainers of plugins making\n+ more sophisticated uses of diagnostics may need to refer to the\n+ porting guide.\n+
      • \n+\n+
    \n+\n+\n+

    Improvements to Static Analyzer

    \n+
      \n+
    • The analyzer is now usable on simple C++ examples, as it now handles\n+ C++'s Named Return Value Optimization and has some initial support for\n+ exceptions. However due to scaling issues it is not likely to be usable\n+ on production C++ code in this release.\n+ \n+ \n+
      • \n+
    • With the added support for exception-handling, -fanalyzer\n+ assumes that a call to an external function not marked with attribute\n+ nothrow could throw an exception if -fexceptions\n+ is enabled. GCC 16 adds a new option\n+ -fanalyzer-assume-nothrow,\n+ for disabling this assumption. This is intended as a workaround for\n+ projects where the exception-handling generates large numbers of new\n+ warnings, such as C code where -fexceptions is used for\n+ interoperability with C++ but where the C APIs in use are unlikely to\n+ throw exceptions.\n+ \n+
      • \n+
    • The data structure used by -fanalyzer for representing\n+ the user's code has been rewritten in a way that makes it easier to\n+ understand and debug, and slightly improves locations used when reporting\n+ diagnostics. This comes at the cost of increasing the memory usage of\n+ the analyzer.\n+ \n+
      • \n+
    • The data structure used by -fanalyzer for simulating the\n+ contents of memory in the user's program has been reimplemented. The new\n+ implementation is faster and easier to maintain.\n+ \n+
      • \n+
    • The analyzer has started to make use of GCC's value_range\n+ machinery, eliminating some false positives.\n+ \n+
      • \n+
    \n+\n+\n+

    Improvements to libgdiagnostics

    \n+libgdiagnostics has gained 37 entrypoints:\n+\n \n \n

    Other significant improvements

    \ndiff --git a/htdocs/gcc-16/porting_to.html b/htdocs/gcc-16/porting_to.html\nindex 6a6e047a..2ab0df6f 100644\n--- a/htdocs/gcc-16/porting_to.html\n+++ b/htdocs/gcc-16/porting_to.html\n@@ -294,5 +294,188 @@ usual alignment without capping the result.\n (And Good Riddance) to -mt -and -D_REENTRANT.\n \n \n+

    Changes affecting plugin authors

    \n+\n+

    GCC's diagnostic machinery has been substantially cleaned up in GCC 16.\n+ Most of the implementation has been moved to a new\n+ gcc/diagnostics/ subdirectory and diagnostics::\n+ namespace, with many fields becoming private. This should\n+ not affect plugins that use just the diagnostic-core.h API,\n+ but plugins making more sophisticated uses of diagnostics may need\n+ updating. The following tables list the types that have been renamed\n+ in GCC 16 and the header files that have been moved.

    \n+\n+\n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+
    Renamed types
    GCC 15 typeGCC 16 typeNotes
    class diagnostic_buffer class diagnostics::buffer
    class diagnostic_client_data_hooks class diagnostics::client_data_hooks
    class diagnostic_client_plugin_info class diagnostics::client_plugin_info
    class diagnostic_column_policy class diagnostics::column_policy
    class diagnostic_context class diagnostics::context
    struct diagnostic_counters struct diagnostics::counters New header: diagnostics/counters.h
    class diagnostic_diagram class diagnostics::diagram
    class diagnostic_event class diagnostics::paths::event
    class diagnostic_event_id_t class diagnostics::paths::event_id_t
    struct diagnostic_info struct diagnostics::diagnostic_info Fields have gained m_ prefixes
    class diagnostic_location_print_policy class diagnostics::location_print_policy
    class diagnostic_metadata class diagnostics::metadata
    class diagnostic_option_classifier class diagnostics::option_classifier
    struct diagnostic_option_id struct diagnostics::option_id New header: diagnostics/option-id.h
    class diagnostic_option_manager class diagnostics::option_manager
    class diagnostic_output_file class diagnostics::output_file
    class diagnostic_output_format class diagnostics::sink
    class diagnostic_per_format_buffer class diagnostics::per_sink_buffer
    struct diagnostic_source_printing_options struct diagnostics::source_printing_options
    class diagnostic_source_print_policy class diagnostics::source_print_policy
    enum diagnostic_t enum class diagnostics::kind
    class diagnostic_text_output_format class diagnostics::text_sink
    class diagnostic_thread class diagnostics::paths::thread
    typedef diagnostic_thread_id_t typedef diagnostics::paths::thread_id_t
    class diagnostic_path class diagnostics::paths::path
    class edit_context class diagnostics::changes::change_set
    class logical_location class diagnostics::logical_locations::key
    enum logical_location_kind enum diagnostics::logical_locations::kind
    class logical_location_manager class diagnostics::logical_locations::manager
    class sarif_output_format class diagnostics::sarif_sink
    class diagnostic_sarif_format_buffer class diagnostics::sarif_sink_buffer
    class option_manager class diagnostics::option_id_manager New header: diagnostics/option-id-manager.h
    \n+\n+\n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+ \n+
    Header file changes
    GCC 15 headerGCC 16 header
    diagnostic-buffer.h diagnostics/buffering.h
    diagnostic-client-data-hooks.h diagnostics/client-data-hooks.h
    diagnostic-color.h diagnostics/color.h
    diagnostic.def diagnostics/kind.def
    diagnostic-diagram.h diagnostics/diagram.h
    diagnostic-format-html.h diagnostics/html-sink.h
    diagnostic-format-sarif.h diagnostics/sarif-sink.h
    diagnostic-format-text.h diagnostics/text-sink.h
    diagnostic-label-effects.h diagnostics/source-printing-effects.h
    diagnostic-macro-unwinding.h diagnostics/macro-unwinding.h
    diagnostic-metadata.h diagnostics/metadata.h
    diagnostic-output-file.h diagnostics/output-file.h
    diagnostic-path.h diagnostics/paths.h
    diagnostic-url.h diagnostics/url.h
    edit-context.h diagnostics/changes.h
    File cache types of input.h diagnostics/file-cache.h
    logical-locations.h diagnostics/logical-locations.h
    \n+\n \n \n","prefixes":["pushed"]}