Adding upstream version 7.0.14-dfsg.upstream/7.0.14-dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1012 insertions, 0 deletions

diff --git a/src/bldprogs/VBoxCompilerPlugInsGcc.cpp b/src/bldprogs/VBoxCompilerPlugInsGcc.cpp
new file mode 100644
index 00000000..04a0a133
--- /dev/null
+++ b/src/bldprogs/VBoxCompilerPlugInsGcc.cpp
@@ -0,0 +1,1012 @@
+/* $Id: VBoxCompilerPlugInsGcc.cpp $ */
+/** @file
+ * gccplugin - GCC plugin for checking IPRT format strings.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <stdio.h>
+#include <iprt/cdefs.h>
+#include <iprt/stdarg.h>
+
+#if RT_GNUC_PREREQ(5, 1)
+# include "gcc-plugin.h"
+# include "plugin-version.h"
+#endif
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 5
+# include "gmp.h"
+extern "C" {
+#endif
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 5
+# include "coretypes.h"
+#endif
+#include "plugin.h"
+#include "basic-block.h"
+#include "tree.h"
+#include "tree-pass.h"
+#if __GNUC__ == 5 && __GNUC_MINOR__ == 4
+# include "tree-ssa-alias.h"
+# include "gimple-expr.h"
+#endif
+#include "gimple.h"
+#if RT_GNUC_PREREQ(4, 9)
+# include "gimple-iterator.h"
+# include "context.h" /* for g */
+#endif
+#include "cp/cp-tree.h"
+#if RT_GNUC_PREREQ(10, 0)
+# include "stringpool.h"
+# include "attribs.h"
+#endif
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 5
+}
+#endif
+
+#include "VBoxCompilerPlugIns.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** License indicator. */
+int plugin_is_GPL_compatible;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Convencience macro not present in earlier gcc versions. */
+#ifndef VAR_P
+# define VAR_P(a_hNode) (TREE_CODE(a_hNode) == VAR_DECL)
+#endif
+/** Replacement for the 4.9.0 get_tree_code_name function. */
+#if !RT_GNUC_PREREQ(4, 9)
+# define get_tree_code_name(a_enmTreeCode) (tree_code_name[a_enmTreeCode])
+#endif
+
+
+/** For use with messages.
+ * @todo needs some more work... Actually, seems we're a bit handicapped by
+ *       working on gimplified stuff. */
+#define MY_LOC(a_hPreferred, a_pState) EXPR_LOC_OR_LOC(a_hPreferred, (a_pState)->hFmtLoc)
+
+/** @name Compatibility glue
+ * @{ */
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 5
+# define linemap_location_from_macro_expansion_p(a, b) false
+#endif
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 5
+static tree gimple_call_fntype(gimple hStmt)
+{
+    tree hDecl = gimple_call_fndecl(hStmt);
+    if (hDecl)
+        return TREE_TYPE(hDecl);
+    hDecl = gimple_call_fn(hStmt);
+    if (TREE_CODE(hDecl) == OBJ_TYPE_REF)
+        hDecl = OBJ_TYPE_REF_EXPR(hDecl);
+    if (DECL_P(hDecl))
+    {
+        tree hType = TREE_TYPE(hDecl);
+        if (POINTER_TYPE_P(hType))
+            hType = TREE_TYPE(hType);
+        return hType;
+    }
+    return NULL_TREE; /* caller bitches about this*/
+}
+#endif
+
+///* Integer to HOST_WIDE_INT conversion fun. */
+//#if RT_GNUC_PREREQ(4, 6)
+//# define MY_INT_FITS_SHWI(hNode)    (hNode).fits_shwi()
+//# define MY_INT_TO_SHWI(hNode)      (hNode).to_shwi()
+//#else
+//# define MY_INT_FITS_SHWI(hNode)    double_int_fits_in_shwi_p(hNode)
+//# define MY_INT_TO_SHWI(hNode)      double_int_to_shwi(hNode)
+//#endif
+
+/* Integer to HOST_WIDE_INT conversion fun. */
+#if RT_GNUC_PREREQ(5, 1)
+# define MY_DOUBLE_INT_FITS_SHWI(hNode)     tree_fits_shwi_p(hNode)
+# define MY_DOUBLE_INT_TO_SHWI(hNode)       tree_to_shwi(hNode)
+#elif RT_GNUC_PREREQ(4, 6)
+# define MY_DOUBLE_INT_FITS_SHWI(hNode)     (TREE_INT_CST(hNode).fits_shwi())
+# define MY_DOUBLE_INT_TO_SHWI(hNode)       (TREE_INT_CST(hNode).to_shwi())
+#else
+# define MY_DOUBLE_INT_FITS_SHWI(hNode)     double_int_fits_in_shwi_p(TREE_INT_CST(hNode))
+# define MY_DOUBLE_INT_TO_SHWI(hNode)       double_int_to_shwi(TREE_INT_CST(hNode))
+#endif
+
+#ifndef EXPR_LOC_OR_LOC
+# define EXPR_LOC_OR_LOC(a,b) (b)
+#endif
+/** @} */
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static bool             MyPassGateCallback(void);
+static unsigned int     MyPassExecuteCallback(void);
+static unsigned int     MyPassExecuteCallbackWithFunction(struct function *pFun);
+static tree             AttributeHandler(tree *, tree, tree, int, bool *);
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Plug-in info. */
+static const struct plugin_info g_PlugInInfo =
+{
+    version: "0.0.0-ALPHA",
+    help   : "Implements the __iprt_format__ attribute for checking format strings and arguments."
+};
+
+#if RT_GNUC_PREREQ(4, 9)
+
+/** My pass. */
+static const pass_data g_MyPassData =
+{
+    type                    : GIMPLE_PASS,
+    name                    : "*iprt-format-checks", /* asterisk = no dump */
+# if RT_GNUC_PREREQ(10, 0)
+    optinfo_flags           : OPTGROUP_NONE,
+# else
+    optinfo_flags           : 0,
+# endif
+    tv_id                   : TV_NONE,
+    properties_required     : 0,
+    properties_provided     : 0,
+    properties_destroyed    : 0,
+    todo_flags_start        : 0,
+    todo_flags_finish       : 0,
+};
+
+class MyPass : public gimple_opt_pass
+{
+public:
+    MyPass(gcc::context *pCtx) : gimple_opt_pass(g_MyPassData, pCtx)
+    { }
+
+    virtual bool gate(function *pFun)
+    {
+        NOREF(pFun);
+        return MyPassGateCallback();
+    }
+
+    virtual unsigned int execute(function *pFun)
+    {
+        NOREF(pFun);
+        return MyPassExecuteCallbackWithFunction(pFun);
+    }
+};
+
+#else /* < 4.9.0 */
+
+/** My pass. */
+static struct gimple_opt_pass g_MyPass =
+{
+    pass:
+    {
+        type                    : GIMPLE_PASS,
+        name                    : "*iprt-format-checks", /* asterisk = no dump */
+# if RT_GNUC_PREREQ(4, 6)
+        optinfo_flags           : 0,
+# endif
+        gate                    : MyPassGateCallback,
+        execute                 : MyPassExecuteCallback,
+        sub                     : NULL,
+        next                    : NULL,
+        static_pass_number      : 0,
+        tv_id                   : TV_NONE,
+        properties_required     : 0,
+        properties_provided     : 0,
+        properties_destroyed    : 0,
+        todo_flags_start        : 0,
+        todo_flags_finish       : 0,
+    }
+};
+
+/** The registration info for my pass. */
+static const struct register_pass_info  g_MyPassInfo =
+{
+    pass                        : &g_MyPass.pass,
+    reference_pass_name         : "ssa",
+    ref_pass_instance_number    : 1,
+    pos_op                      : PASS_POS_INSERT_BEFORE,
+};
+
+#endif /* < 4.9.0 */
+
+
+/** Attribute specifications. */
+static const struct attribute_spec g_AttribSpecs[] =
+{
+    {
+        name                    : "iprt_format",
+        min_length              : 2,
+        max_length              : 2,
+        decl_required           : false,
+        type_required           : true,
+        function_type_required  : true,
+// gcc 7.3 at least moves this field to after "handler", and with 8.3 it is back
+#if RT_GNUC_PREREQ(4, 6) && !(RT_GNUC_PREREQ(7, 0) && !RT_GNUC_PREREQ(8, 0))
+        affects_type_identity   : false,
+#endif
+        handler                 : AttributeHandler,
+#if RT_GNUC_PREREQ(7, 0) && !RT_GNUC_PREREQ(8, 0)
+        affects_type_identity   : false,
+#endif
+#if RT_GNUC_PREREQ(8, 0)
+        exclude                 : NULL,
+#endif
+    },
+    {
+        name                    : "iprt_format_maybe_null",
+        min_length              : 2,
+        max_length              : 2,
+        decl_required           : false,
+        type_required           : true,
+        function_type_required  : true,
+#if RT_GNUC_PREREQ(4, 6) && !(RT_GNUC_PREREQ(7, 0) && !RT_GNUC_PREREQ(8, 0))
+        affects_type_identity   : false,
+#endif
+        handler                 : AttributeHandler,
+#if RT_GNUC_PREREQ(7, 0) && !RT_GNUC_PREREQ(8, 0)
+        affects_type_identity   : false,
+#endif
+#if RT_GNUC_PREREQ(8, 0)
+        exclude                 : NULL,
+#endif
+    }
+};
+
+
+#ifdef DEBUG
+
+/**
+ * Debug function for printing the scope of a decl.
+ * @param   hDecl               Declaration to print scope for.
+ */
+static void dprintScope(tree hDecl)
+{
+# if 0 /* later? */
+    tree hScope = CP_DECL_CONTEXT(hDecl);
+    if (hScope == global_namespace)
+        return;
+    if (TREE_CODE(hScope) == RECORD_TYPE)
+        hScope = TYPE_NAME(hScope);
+
+    /* recurse */
+    dprintScope(hScope);
+
+    /* name the scope. */
+    dprintf("::%s", DECL_NAME(hScope) ? IDENTIFIER_POINTER(DECL_NAME(hScope)) : "<noname>");
+# endif
+}
+
+
+/**
+ * Debug function for printing a declaration.
+ * @param   hDecl               The declaration to print.
+ */
+static void dprintDecl(tree hDecl)
+{
+    enum tree_code const    enmDeclCode = TREE_CODE(hDecl);
+    tree const              hType       = TREE_TYPE(hDecl);
+    enum tree_code const    enmTypeCode = hType ? TREE_CODE(hType) : (enum tree_code)-1;
+#if 0
+    if (   enmTypeCode == RECORD_TYPE
+        && enmDeclCode == TYPE_DECL
+        && DECL_ARTIFICIAL(hDecl))
+        dprint_class(hType);
+#endif
+
+    dprintf("%s ", get_tree_code_name(enmDeclCode));
+    dprintScope(hDecl);
+    dprintf("::%s", DECL_NAME(hDecl) ? IDENTIFIER_POINTER(DECL_NAME(hDecl)) : "<noname>");
+    if (hType)
+        dprintf(" type %s", get_tree_code_name(enmTypeCode));
+    dprintf(" @%s:%d", DECL_SOURCE_FILE(hDecl),  DECL_SOURCE_LINE(hDecl));
+}
+
+#endif /* DEBUG */
+
+
+static location_t MyGetLocationPlusColumnOffset(location_t hLoc, unsigned int offColumn)
+{
+    /*
+     * Skip NOOPs, reserved locations and macro expansion.
+     */
+    if (   offColumn != 0
+        && hLoc >= RESERVED_LOCATION_COUNT
+        && !linemap_location_from_macro_expansion_p(line_table, hLoc))
+    {
+#if __GNUC__ >= 5 /** @todo figure this... */
+        /*
+         * There is an API for doing this, nice.
+         */
+        location_t hNewLoc = linemap_position_for_loc_and_offset(line_table, hLoc, offColumn);
+        if (hNewLoc && hNewLoc != hLoc)
+        {
+            dprintf("MyGetLocationPlusColumnOffset: hNewLoc=%#x hLoc=%#x offColumn=%u\n", hNewLoc, hLoc, offColumn);
+            return hNewLoc;
+        }
+
+#elif __GNUC_MINOR__ > 5
+        /*
+         * Have to do the job ourselves, it seems.  This is a bit hairy...
+         */
+        line_map const *pMap = NULL;
+        location_t hLoc2 = linemap_resolve_location(line_table, hLoc, LRK_SPELLING_LOCATION, &pMap);
+        if (hLoc2)
+            hLoc = hLoc2;
+
+        /* Guard against wrap arounds and overlaps. */
+        if (   hLoc + offColumn > MAP_START_LOCATION(pMap) /** @todo Use MAX_SOURCE_LOCATION? */
+            && (   pMap == LINEMAPS_LAST_ORDINARY_MAP(line_table)
+                || hLoc + offColumn < MAP_START_LOCATION((pMap + 1))))
+        {
+            /* Calc new column and check that it's within the valid range. */
+            unsigned int uColumn = SOURCE_COLUMN(pMap, hLoc) + offColumn;
+            if (uColumn < RT_BIT_32(ORDINARY_MAP_NUMBER_OF_COLUMN_BITS(pMap)))
+            {
+                /* Try add the position.  If we get a valid result, replace the location. */
+                source_location hNewLoc = linemap_position_for_line_and_column((line_map *)pMap, SOURCE_LINE(pMap, hLoc), uColumn);
+                if (   hNewLoc <= line_table->highest_location
+                    && linemap_lookup(line_table, hNewLoc) != NULL)
+                {
+                    dprintf("MyGetLocationPlusColumnOffset: hNewLoc=%#x hLoc=%#x offColumn=%u uColumn=%u\n",
+                            hNewLoc, hLoc, offColumn, uColumn);
+                    return hNewLoc;
+                }
+            }
+        }
+#endif
+    }
+    dprintf("MyGetLocationPlusColumnOffset: taking fallback\n");
+    return hLoc;
+}
+
+
+#if 0
+DECLINLINE(int) MyGetLineLength(const char *pszLine)
+{
+    if (pszLine)
+    {
+        const char *pszEol = strpbrk(pszLine, "\n\r");
+        if (!pszEol)
+            pszEol = strchr(pszLine, '\0');
+        return (int)(pszEol - pszLine);
+    }
+    return 0;
+}
+#endif
+
+static location_t MyGetFormatStringLocation(PVFMTCHKSTATE pState, const char *pszLoc)
+{
+    location_t hLoc = pState->hFmtLoc;
+#if RT_GNUC_PREREQ(4,6)
+    intptr_t   offString = pszLoc - pState->pszFmt;
+    if (   offString >= 0
+        && !linemap_location_from_macro_expansion_p(line_table, hLoc))
+    {
+        unsigned            uCol    = 1 + offString;
+# if 0 /* apparently not needed */
+        expanded_location   XLoc    = expand_location_to_spelling_point(hLoc);
+# if RT_GNUC_PREREQ(10,0)
+        char_span           Span    = location_get_source_line(XLoc.file, XLoc.line);
+        const char         *pszLine = Span.m_ptr; /** @todo if enabled */
+        int                 cchLine = (int)Span.m_n_elts;
+# elif RT_GNUC_PREREQ(6,0)
+        int                 cchLine = 0;
+        const char         *pszLine = location_get_source_line(XLoc.file, XLoc.line, &cchLine);
+# elif RT_GNUC_PREREQ(5,0)
+        int                 cchLine = 0;
+        const char         *pszLine = location_get_source_line(XLoc, &cchLine);
+# else
+        const char         *pszLine = location_get_source_line(XLoc);
+        int                 cchLine = MyGetLineLength(pszLine);
+# endif
+        if (pszLine)
+        {
+            /** @todo Adjust the position by parsing the source. */
+            pszLine += XLoc.column - 1;
+            cchLine -= XLoc.column - 1;
+        }
+# endif
+
+        hLoc = MyGetLocationPlusColumnOffset(hLoc, uCol);
+    }
+#endif
+    return hLoc;
+}
+
+
+/**
+ * Non-recursive worker for MyCheckFormatRecursive.
+ *
+ * This will attempt to result @a hFmtArg into a string literal which it then
+ * passes on to MyCheckFormatString for the actual analyzis.
+ *
+ * @param   pState              The format string checking state.
+ * @param   hFmtArg             The format string node.
+ */
+DECL_NO_INLINE(static, void) MyCheckFormatNonRecursive(PVFMTCHKSTATE pState, tree hFmtArg)
+{
+    dprintf("checker: hFmtArg=%p %s\n", hFmtArg, get_tree_code_name(TREE_CODE(hFmtArg)));
+
+    /*
+     * Try resolve variables into constant strings.
+     */
+    if (VAR_P(hFmtArg))
+    {
+        hFmtArg = decl_constant_value(hFmtArg);
+        STRIP_NOPS(hFmtArg); /* Used as argument and assigned call result. */
+        dprintf("checker1: variable => hFmtArg=%p %s\n", hFmtArg, get_tree_code_name(TREE_CODE(hFmtArg)));
+    }
+
+    /*
+     * Fend off NULLs.
+     */
+    if (integer_zerop(hFmtArg))
+    {
+        if (pState->fMaybeNull)
+            VFmtChkVerifyEndOfArgs(pState, 0);
+        else
+            error_at(MY_LOC(hFmtArg, pState), "Format string should not be NULL");
+    }
+    /*
+     * Need address expression to get any further.
+     */
+    else if (TREE_CODE(hFmtArg) != ADDR_EXPR)
+        dprintf("checker1: Not address expression (%s)\n", get_tree_code_name(TREE_CODE(hFmtArg)));
+    else
+    {
+        pState->hFmtLoc = EXPR_LOC_OR_LOC(hFmtArg, pState->hFmtLoc);
+        hFmtArg = TREE_OPERAND(hFmtArg, 0);
+
+        /*
+         * Deal with fixed string indexing, if possible.
+         */
+        HOST_WIDE_INT off = 0;
+        if (   TREE_CODE(hFmtArg) == ARRAY_REF
+            && MY_DOUBLE_INT_FITS_SHWI(TREE_OPERAND(hFmtArg, 1))
+            && MY_DOUBLE_INT_FITS_SHWI(TREE_OPERAND(hFmtArg, 1)) )
+        {
+            off = MY_DOUBLE_INT_TO_SHWI(TREE_OPERAND(hFmtArg, 1));
+            if (off < 0)
+            {
+                dprintf("checker1: ARRAY_REF, off=%ld\n", off);
+                return;
+            }
+            hFmtArg = TREE_OPERAND(hFmtArg, 0);
+            dprintf("checker1: ARRAY_REF => hFmtArg=%p %s, off=%ld\n", hFmtArg, get_tree_code_name(TREE_CODE(hFmtArg)), off);
+        }
+
+        /*
+         * Deal with static const char g_szFmt[] = "qwerty";  Take care as
+         * the actual string constant may not necessarily include the terminator.
+         */
+        tree hArraySize = NULL_TREE;
+        if (   VAR_P(hFmtArg)
+            && TREE_CODE(TREE_TYPE(hFmtArg)) == ARRAY_TYPE)
+        {
+            tree hArrayInitializer = decl_constant_value(hFmtArg);
+            if (   hArrayInitializer != hFmtArg
+                && TREE_CODE(hArrayInitializer) == STRING_CST)
+            {
+                hArraySize = DECL_SIZE_UNIT(hFmtArg);
+                hFmtArg = hArrayInitializer;
+            }
+        }
+
+        /*
+         * Are we dealing with a string literal now?
+         */
+        if (TREE_CODE(hFmtArg) != STRING_CST)
+            dprintf("checker1: Not string literal (%s)\n", get_tree_code_name(TREE_CODE(hFmtArg)));
+        else if (TYPE_MAIN_VARIANT(TREE_TYPE(TREE_TYPE(hFmtArg))) != char_type_node)
+            warning_at(pState->hFmtLoc, 0, "expected 'char' type string literal");
+        else
+        {
+            /*
+             * Yes we are, so get the pointer to the string and its length.
+             */
+            const char *pszFmt = TREE_STRING_POINTER(hFmtArg);
+            int         cchFmt = TREE_STRING_LENGTH(hFmtArg);
+
+            /* Adjust cchFmt to the initialized array size if appropriate. */
+            if (hArraySize != NULL_TREE)
+            {
+                if (TREE_CODE(hArraySize) != INTEGER_CST)
+                    warning_at(pState->hFmtLoc, 0, "Expected integer array size (not %s)", get_tree_code_name(TREE_CODE(hArraySize)));
+                else if (!MY_DOUBLE_INT_FITS_SHWI(hArraySize))
+                    warning_at(pState->hFmtLoc, 0, "Unexpected integer overflow in array size constant");
+                else
+                {
+                    HOST_WIDE_INT cbArray = MY_DOUBLE_INT_TO_SHWI(hArraySize);
+                    if (   cbArray <= 0
+                        || cbArray != (int)cbArray)
+                        warning_at(pState->hFmtLoc, 0, "Unexpected integer array size constant value: %ld", cbArray);
+                    else if (cchFmt > cbArray)
+                    {
+                        dprintf("checker1: cchFmt=%d => cchFmt=%ld (=cbArray)\n", cchFmt, cbArray);
+                        cchFmt = (int)cbArray;
+                    }
+                }
+            }
+
+            /* Apply the offset, if given. */
+            if (off)
+            {
+                if (off >= cchFmt)
+                {
+                    dprintf("checker1: off=%ld  >=  cchFmt=%d -> skipping\n", off, cchFmt);
+                    return;
+                }
+                pszFmt += off;
+                cchFmt -= (int)off;
+            }
+
+            /*
+             * Check for unterminated strings.
+             */
+            if (   cchFmt < 1
+                || pszFmt[cchFmt - 1] != '\0')
+                warning_at(pState->hFmtLoc, 0, "Unterminated format string (cchFmt=%d)", cchFmt);
+            /*
+             * Call worker to check the actual string.
+             */
+            else
+                MyCheckFormatCString(pState, pszFmt);
+        }
+    }
+}
+
+
+/**
+ * Deal recursively with special format string constructs.
+ *
+ * This will call MyCheckFormatNonRecursive to validate each format string.
+ *
+ * @param   pState              The format string checking state.
+ * @param   hFmtArg             The format string node.
+ */
+static void MyCheckFormatRecursive(PVFMTCHKSTATE pState, tree hFmtArg)
+{
+    /*
+     * Catch wrong attribute use.
+     */
+    if (hFmtArg == NULL_TREE)
+        error_at(pState->hFmtLoc, "IPRT format attribute is probably used incorrectly (hFmtArg is NULL)");
+    /*
+     * NULL format strings may cause crashes.
+     */
+    else if (integer_zerop(hFmtArg))
+    {
+        if (pState->fMaybeNull)
+            VFmtChkVerifyEndOfArgs(pState, 0);
+        else
+            error_at(MY_LOC(hFmtArg, pState), "Format string should not be NULL");
+    }
+    /*
+     * Check both branches of a ternary operator.
+     */
+    else if (TREE_CODE(hFmtArg) == COND_EXPR)
+    {
+        MyCheckFormatRecursive(pState, TREE_OPERAND(hFmtArg, 1));
+        MyCheckFormatRecursive(pState, TREE_OPERAND(hFmtArg, 2));
+    }
+    /*
+     * Strip coercion.
+     */
+    else if (   CONVERT_EXPR_P(hFmtArg)
+             && TYPE_PRECISION(TREE_TYPE(hFmtArg)) == TYPE_PRECISION(TREE_TYPE(TREE_OPERAND(hFmtArg, 0))) )
+        MyCheckFormatRecursive(pState, TREE_OPERAND(hFmtArg, 0));
+    /*
+     * We're good, hand it to the non-recursive worker.
+     */
+    else
+        MyCheckFormatNonRecursive(pState, hFmtArg);
+}
+
+
+#if !RT_GNUC_PREREQ(4, 9)
+/**
+ * Execute my pass.
+ * @returns Flags indicates stuff todo, we return 0.
+ */
+static unsigned int     MyPassExecuteCallback(void)
+{
+    return MyPassExecuteCallbackWithFunction(cfun);
+}
+#endif
+
+/**
+ * Execute my pass.
+ * @returns Flags indicates stuff todo, we return 0.
+ */
+static unsigned int     MyPassExecuteCallbackWithFunction(struct function *pFun)
+{
+    dprintf("MyPassExecuteCallback:\n");
+
+    /*
+     * Enumerate the basic blocks.
+     */
+    basic_block hBasicBlock;
+    FOR_EACH_BB_FN(hBasicBlock, pFun)
+    {
+        dprintf(" hBasicBlock=%p\n", hBasicBlock);
+
+        /*
+         * Enumerate the statements in the current basic block.
+         * We're interested in calls to functions with the __iprt_format__ attribute.
+         */
+        for (gimple_stmt_iterator hStmtItr = gsi_start_bb(hBasicBlock); !gsi_end_p(hStmtItr); gsi_next(&hStmtItr))
+        {
+#if RT_GNUC_PREREQ(6, 0)
+            const gimple * const    hStmt   = gsi_stmt(hStmtItr);
+#else
+            gimple const            hStmt   = gsi_stmt(hStmtItr);
+#endif
+
+            enum gimple_code const  enmCode = gimple_code(hStmt);
+#ifdef DEBUG
+            unsigned const          cOps    = gimple_num_ops(hStmt);
+            dprintf("   hStmt=%p %s (%d) ops=%d\n", hStmt, gimple_code_name[enmCode], enmCode, cOps);
+            for (unsigned iOp = 0; iOp < cOps; iOp++)
+            {
+                tree const hOp = gimple_op(hStmt, iOp);
+                if (hOp)
+                    dprintf("     %02d: %p, code %s(%d)\n", iOp, hOp, get_tree_code_name(TREE_CODE(hOp)), TREE_CODE(hOp));
+                else
+                    dprintf("     %02d: NULL_TREE\n", iOp);
+            }
+#endif
+            if (enmCode == GIMPLE_CALL)
+            {
+                /*
+                 * Check if the function type has the __iprt_format__ attribute.
+                 */
+                tree const hFn = gimple_call_fn(hStmt);
+                dprintf("     hFn    =%p %s(%d); args=%d\n",
+                        hFn, hFn ? get_tree_code_name(TREE_CODE(hFn)) : NULL, hFn ? TREE_CODE(hFn) : - 1,
+                        gimple_call_num_args(hStmt));
+#ifdef DEBUG
+                if (hFn && DECL_P(hFn))
+                    dprintf("     hFn is decl: %s %s:%d\n",
+                            DECL_NAME(hFn) ? IDENTIFIER_POINTER(DECL_NAME(hFn)) : "<unamed>",
+                            DECL_SOURCE_FILE(hFn), DECL_SOURCE_LINE(hFn));
+#endif
+                tree const hFnDecl = gimple_call_fndecl(hStmt);
+                if (hFnDecl)
+                    dprintf("     hFnDecl=%p %s(%d) %s type=%p %s:%d\n",
+                            hFnDecl, get_tree_code_name(TREE_CODE(hFnDecl)), TREE_CODE(hFnDecl),
+                            DECL_NAME(hFnDecl) ? IDENTIFIER_POINTER(DECL_NAME(hFnDecl)) : "<unamed>",
+                            TREE_TYPE(hFnDecl), DECL_SOURCE_FILE(hFnDecl), DECL_SOURCE_LINE(hFnDecl));
+                tree const hFnType = gimple_call_fntype(hStmt);
+                if (hFnType == NULL_TREE)
+                {
+                    if (   hFnDecl == NULL_TREE
+                        && gimple_call_internal_p(hStmt) /* va_arg() kludge */)
+                        continue;
+                    error_at(gimple_location(hStmt), "Failed to resolve function type [fn=%s fndecl=%s]\n",
+                             hFn ? get_tree_code_name(TREE_CODE(hFn)) : "<null>",
+                             hFnDecl ? get_tree_code_name(TREE_CODE(hFnDecl)) : "<null>");
+                }
+                else if (POINTER_TYPE_P(hFnType))
+                    error_at(gimple_location(hStmt), "Got a POINTER_TYPE when expecting a function type [fn=%s]\n",
+                             get_tree_code_name(TREE_CODE(hFn)));
+                if (hFnType)
+                    dprintf("     hFnType=%p %s(%d) %s\n", hFnType, get_tree_code_name(TREE_CODE(hFnType)), TREE_CODE(hFnType),
+                              TYPE_NAME(hFnType) && DECL_NAME(TYPE_NAME(hFnType))
+                            ? IDENTIFIER_POINTER(DECL_NAME(TYPE_NAME(hFnType))) : "<unamed>");
+
+                tree const hAttr        = hFnType ? lookup_attribute("iprt_format", TYPE_ATTRIBUTES(hFnType))            : NULL_TREE;
+                tree const hAttrMaybe0  = hFnType ? lookup_attribute("iprt_format_maybe_null", TYPE_ATTRIBUTES(hFnType)) : NULL_TREE;
+                if (hAttr || hAttrMaybe0)
+                {
+                    /*
+                     * Yeah, it has the attribute!
+                     */
+                    tree const hAttrArgs = hAttr ? TREE_VALUE(hAttr) : TREE_VALUE(hAttrMaybe0);
+                    VFMTCHKSTATE State;
+                    State.iFmt          = MY_DOUBLE_INT_TO_SHWI(TREE_VALUE(hAttrArgs));
+                    State.iArgs         = MY_DOUBLE_INT_TO_SHWI(TREE_VALUE(TREE_CHAIN(hAttrArgs)));
+                    State.pszFmt        = NULL;
+                    State.fMaybeNull    = hAttr == NULL_TREE;
+                    State.hStmt         = hStmt;
+                    State.hFmtLoc       = gimple_location(hStmt);
+                    dprintf("     %s() __iprt_format%s__(iFmt=%ld, iArgs=%ld)\n",
+                            hFnDecl && DECL_NAME(hFnDecl) ? IDENTIFIER_POINTER(DECL_NAME(hFnDecl)) : "<unamed>",
+                            State.fMaybeNull ? "_maybe_null" : "", State.iFmt, State.iArgs);
+
+                    unsigned cCallArgs = gimple_call_num_args(hStmt);
+                    if (cCallArgs >= State.iFmt)
+                        MyCheckFormatRecursive(&State, gimple_call_arg(hStmt, State.iFmt - 1));
+                    else
+                        error_at(gimple_location(hStmt),
+                                 "Call has only %d arguments; %s() format string is argument #%lu (1-based), thus missing\n",
+                                 cCallArgs, DECL_NAME(hFnDecl) ? IDENTIFIER_POINTER(DECL_NAME(hFnDecl)) : "<unamed>", State.iFmt);
+                }
+            }
+        }
+    }
+    return 0;
+}
+
+
+/**
+ * Gate callback for my pass that indicates whether it should execute or not.
+ * @returns true to execute.
+ */
+static bool             MyPassGateCallback(void)
+{
+    dprintf("MyPassGateCallback:\n");
+    return true;
+}
+
+
+/**
+ * Validate the use of an attribute.
+ *
+ * @returns ??
+ * @param   phOnNode        The node the attribute is being used on.
+ * @param   hAttrName       The attribute name.
+ * @param   hAttrArgs       The attribute arguments.
+ * @param   fFlags          Some kind of flags...
+ * @param   pfDontAddAttrib Whether to add the attribute to this node or not.
+ */
+static tree AttributeHandler(tree *phOnNode, tree hAttrName, tree hAttrArgs, int fFlags, bool *pfDontAddAttrib)
+{
+    dprintf("AttributeHandler: name=%s fFlags=%#x", IDENTIFIER_POINTER(hAttrName), fFlags);
+    long iFmt  = MY_DOUBLE_INT_TO_SHWI(TREE_VALUE(hAttrArgs));
+    long iArgs = MY_DOUBLE_INT_TO_SHWI(TREE_VALUE(TREE_CHAIN(hAttrArgs)));
+    dprintf(" iFmt=%ld iArgs=%ld", iFmt, iArgs);
+
+    tree hType = *phOnNode;
+    dprintf(" hType=%p %s(%d)\n", hType, get_tree_code_name(TREE_CODE(hType)), TREE_CODE(hType));
+
+    if (pfDontAddAttrib)
+        *pfDontAddAttrib = false;
+    return NULL_TREE;
+}
+
+
+/**
+ * Called when we can register attributes.
+ *
+ * @param   pvEventData         Ignored.
+ * @param   pvUser              Ignored.
+ */
+static void RegisterAttributesEvent(void *pvEventData, void *pvUser)
+{
+    NOREF(pvEventData); NOREF(pvUser);
+    dprintf("RegisterAttributesEvent: pvEventData=%p\n", pvEventData);
+
+    register_attribute(&g_AttribSpecs[0]);
+    register_attribute(&g_AttribSpecs[1]);
+}
+
+
+/**
+ * The plug-in entry point.
+ *
+ * @returns 0 to indicate success?
+ * @param   pPlugInInfo         Plugin info structure.
+ * @param   pGccVer             GCC Version.
+ */
+int plugin_init(plugin_name_args *pPlugInInfo, plugin_gcc_version *pGccVer)
+{
+    dprintf("plugin_init: %s\n", pPlugInInfo->full_name);
+    dprintf("gcc version: basever=%s datestamp=%s devphase=%s revision=%s\n",
+            pGccVer->basever, pGccVer->datestamp, pGccVer->devphase, pGccVer->revision);
+
+    /* Ask for callback in which we may register the attribute. */
+    register_callback(pPlugInInfo->base_name, PLUGIN_ATTRIBUTES, RegisterAttributesEvent, NULL /*pvUser*/);
+
+    /* Register our pass. */
+#if RT_GNUC_PREREQ(4, 9)
+    /** The registration info for my pass. */
+    struct register_pass_info MyPassInfo;
+    MyPassInfo.pass                     = new MyPass(g);
+    MyPassInfo.reference_pass_name      = "ssa";
+    MyPassInfo.ref_pass_instance_number = 1;
+    MyPassInfo.pos_op                   = PASS_POS_INSERT_BEFORE;
+    register_callback(pPlugInInfo->base_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &MyPassInfo);
+#else
+    register_callback(pPlugInInfo->base_name, PLUGIN_PASS_MANAGER_SETUP, NULL, (void *)&g_MyPassInfo);
+#endif
+
+    /* Register plug-in info. */
+    register_callback(pPlugInInfo->base_name, PLUGIN_INFO, NULL, (void *)&g_PlugInInfo);
+
+    return 0;
+}
+
+
+
+
+/*
+ *
+ * Functions used by the common code.
+ * Functions used by the common code.
+ * Functions used by the common code.
+ *
+ */
+
+void VFmtChkWarnFmt(PVFMTCHKSTATE pState, const char *pszLoc, const char *pszFormat, ...)
+{
+    char szTmp[1024];
+    va_list va;
+    va_start(va, pszFormat);
+    vsnprintf(szTmp, sizeof(szTmp), pszFormat, va);
+    va_end(va);
+
+    /* display the warning. */
+    warning_at(MyGetFormatStringLocation(pState, pszLoc), 0, "%s", szTmp);
+}
+
+
+void VFmtChkErrFmt(PVFMTCHKSTATE pState, const char *pszLoc, const char *pszFormat, ...)
+{
+    char szTmp[1024];
+    va_list va;
+    va_start(va, pszFormat);
+    vsnprintf(szTmp, sizeof(szTmp), pszFormat, va);
+    va_end(va);
+
+    /* display the warning. */
+    error_at(MyGetFormatStringLocation(pState, pszLoc), "%s", szTmp);
+}
+
+
+
+void VFmtChkVerifyEndOfArgs(PVFMTCHKSTATE pState, unsigned iArg)
+{
+    dprintf("VFmtChkVerifyEndOfArgs: iArg=%u iArgs=%ld cArgs=%u\n", iArg, pState->iArgs, gimple_call_num_args(pState->hStmt));
+    if (pState->iArgs > 0)
+    {
+        iArg += pState->iArgs - 1;
+        unsigned cArgs = gimple_call_num_args(pState->hStmt);
+        if (iArg == cArgs)
+        { /* fine */ }
+        else if (iArg < cArgs)
+        {
+            tree hArg = gimple_call_arg(pState->hStmt, iArg);
+            if (cArgs - iArg > 1)
+                error_at(MY_LOC(hArg, pState), "%u extra arguments not consumed by format string", cArgs - iArg);
+            else if (   TREE_CODE(hArg) != INTEGER_CST
+                     || !MY_DOUBLE_INT_FITS_SHWI(hArg)
+                     || MY_DOUBLE_INT_TO_SHWI(hArg) != -99) /* ignore final dummy argument: ..., -99); */
+                error_at(MY_LOC(hArg, pState), "one extra argument not consumed by format string");
+        }
+        /* This should be handled elsewhere, but just in case. */
+        else if (iArg - 1 == cArgs)
+            error_at(pState->hFmtLoc, "one argument too few");
+        else
+            error_at(pState->hFmtLoc, "%u arguments too few", iArg - cArgs);
+    }
+}
+
+
+bool VFmtChkRequirePresentArg(PVFMTCHKSTATE pState, const char *pszLoc, unsigned iArg, const char *pszMessage)
+{
+    if (pState->iArgs > 0)
+    {
+        iArg += pState->iArgs - 1;
+        unsigned cArgs = gimple_call_num_args(pState->hStmt);
+        if (iArg >= cArgs)
+        {
+            VFmtChkErrFmt(pState, pszLoc, "Missing argument! %s", pszMessage);
+            return false;
+        }
+
+        tree hArg  = gimple_call_arg(pState->hStmt, iArg);
+        tree hType = TREE_TYPE(hArg);
+        dprintf("arg%u: hArg=%p [%s] hType=%p [%s] cls=%s\n", iArg, hArg, get_tree_code_name(TREE_CODE(hArg)),
+                hType, get_tree_code_name(TREE_CODE(hType)), tree_code_class_strings[TREE_CODE_CLASS(TREE_CODE(hType))]);
+        dprintf("      nm=%p\n", TYPE_NAME(hType));
+        dprintf("      cb=%p %s value=%ld\n", TYPE_SIZE(hType), get_tree_code_name(TREE_CODE(TYPE_SIZE(hType))),
+                MY_DOUBLE_INT_TO_SHWI(TYPE_SIZE(hType)) );
+        dprintf("      unit=%p %s value=%ld\n", TYPE_SIZE_UNIT(hType), get_tree_code_name(TREE_CODE(TYPE_SIZE_UNIT(hType))),
+                MY_DOUBLE_INT_TO_SHWI(TYPE_SIZE_UNIT(hType)) );
+        tree hTypeNm = TYPE_NAME(hType);
+        if (hTypeNm)
+            dprintf("      typenm=%p %s '%s'\n", hTypeNm, get_tree_code_name(TREE_CODE(hTypeNm)),
+                    IDENTIFIER_POINTER(DECL_NAME(hTypeNm)));
+    }
+    return true;
+}
+
+
+bool VFmtChkRequireIntArg(PVFMTCHKSTATE pState, const char *pszLoc, unsigned iArg, const char *pszMessage)
+{
+    if (VFmtChkRequirePresentArg(pState, pszLoc, iArg, pszMessage))
+    {
+        /** @todo type check.  */
+        return true;
+    }
+    return false;
+}
+
+
+bool VFmtChkRequireStringArg(PVFMTCHKSTATE pState, const char *pszLoc, unsigned iArg, const char *pszMessage)
+{
+    if (VFmtChkRequirePresentArg(pState, pszLoc, iArg, pszMessage))
+    {
+        /** @todo type check.  */
+        return true;
+    }
+    return false;
+}
+
+
+bool VFmtChkRequireVaListPtrArg(PVFMTCHKSTATE pState, const char *pszLoc, unsigned iArg, const char *pszMessage)
+{
+    if (VFmtChkRequirePresentArg(pState, pszLoc, iArg, pszMessage))
+    {
+        /** @todo type check.  */
+        return true;
+    }
+    return false;
+}
+
+
+void VFmtChkHandleReplacementFormatString(PVFMTCHKSTATE pState, const char *pszPctM, unsigned iArg)
+{
+    if (pState->iArgs > 0)
+    {
+        pState->iFmt        = pState->iArgs + iArg;
+        pState->iArgs       = pState->iFmt  + 1;
+        pState->fMaybeNull  = false;
+        MyCheckFormatRecursive(pState, gimple_call_arg(pState->hStmt, pState->iFmt - 1));
+    }
+}
+
+
+const char  *VFmtChkGetFmtLocFile(PVFMTCHKSTATE pState)
+{
+    return LOCATION_FILE(pState->hFmtLoc);
+}
+
+
+unsigned int VFmtChkGetFmtLocLine(PVFMTCHKSTATE pState)
+{
+    return LOCATION_LINE(pState->hFmtLoc);
+}
+
+
+unsigned int VFmtChkGetFmtLocColumn(PVFMTCHKSTATE pState)
+{
+#ifdef LOCATION_COLUMN
+    return LOCATION_COLUMN(pState->hFmtLoc);
+#else
+    return 1;
+#endif
+}
+