From dde6f5eaea5f1611238e9b68f6d9989fb48ddb42 Mon Sep 17 00:00:00 2001
From: PKEuS <philipp@pkeus.de>
Date: Mon, 20 Jun 2016 09:30:41 +0200
Subject: [PATCH] Do not warn about alloca() in C89 mode (#7558)

---
 lib/checkfunctions.cpp | 15 ++++++++-------
 test/testfunctions.cpp |  6 ++++++
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/lib/checkfunctions.cpp b/lib/checkfunctions.cpp
index 88d79b992..e7fac6dcc 100644
--- a/lib/checkfunctions.cpp
+++ b/lib/checkfunctions.cpp
@@ -48,13 +48,14 @@ void CheckFunctions::checkProhibitedFunctions()
             if (tok->isName() && tok->varId() == 0 && tok->strAt(1) == "(") {
                 // alloca() is special as it depends on the code being C or C++, so it is not in Library
                 if (checkAlloca && Token::simpleMatch(tok, "alloca (") && (!tok->function() || tok->function()->nestedIn->type == Scope::eGlobal)) {
-                    if (_tokenizer->isC())
-                        reportError(tok, Severity::warning, "allocaCalled",
-                                    "Obsolete function 'alloca' called. In C99 and later it is recommended to use a variable length array instead.\n"
-                                    "The obsolete function 'alloca' is called. In C99 and later it is recommended to use a variable length array or "
-                                    "a dynamically allocated array instead. The function 'alloca' is dangerous for many reasons "
-                                    "(http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice and http://linux.die.net/man/3/alloca).");
-                    else
+                    if (_tokenizer->isC()) {
+                        if (_settings->standards.c > Standards::C89)
+                            reportError(tok, Severity::warning, "allocaCalled",
+                                        "Obsolete function 'alloca' called. In C99 and later it is recommended to use a variable length array instead.\n"
+                                        "The obsolete function 'alloca' is called. In C99 and later it is recommended to use a variable length array or "
+                                        "a dynamically allocated array instead. The function 'alloca' is dangerous for many reasons "
+                                        "(http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice and http://linux.die.net/man/3/alloca).");
+                    } else
                         reportError(tok, Severity::warning, "allocaCalled",
                                     "Obsolete function 'alloca' called.\n"
                                     "The obsolete function 'alloca' is called. In C++11 and later it is recommended to use std::array<> or "
diff --git a/test/testfunctions.cpp b/test/testfunctions.cpp
index fb2a547ff..653ce3290 100644
--- a/test/testfunctions.cpp
+++ b/test/testfunctions.cpp
@@ -246,6 +246,12 @@ private:
               "}", "test.cpp");  // #4382 - there are no VLAs in C++
         ASSERT_EQUALS("", errout.str());
 
+        check("void f()\n"
+              "{\n"
+              "    char *x = alloca(10);\n"
+              "}", "test.c"); // #7558 - no alternative to alloca in C89
+        ASSERT_EQUALS("", errout.str());
+
         check("void f()\n"
               "{\n"
               "    char *x = alloca(10);\n"