From 107eea236f3db04f759471f89530c5eb497283bb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Wed, 24 May 2023 10:33:53 +0200
Subject: [PATCH] Improved handling of alignas. alignas will not be removed
 from now on so we don't loose this information. (#5081)

---
 lib/symboldatabase.cpp      |  3 +++
 lib/tokenize.cpp            | 19 +++++--------------
 lib/tokenize.h              |  3 ---
 test/testsymboldatabase.cpp | 10 ++++++++++
 test/testvarid.cpp          |  9 +++++++++
 5 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/lib/symboldatabase.cpp b/lib/symboldatabase.cpp
index 5c34877e8..cc0acb6cb 100644
--- a/lib/symboldatabase.cpp
+++ b/lib/symboldatabase.cpp
@@ -4761,6 +4761,9 @@ bool Scope::isVariableDeclaration(const Token* const tok, const Token*& vartok,
     const Token* localTypeTok = skipScopeIdentifiers(tok);
     const Token* localVarTok = nullptr;
 
+    while (Token::simpleMatch(localTypeTok, "alignas (") && Token::Match(localTypeTok->linkAt(1), ") %name%"))
+        localTypeTok = localTypeTok->linkAt(1)->next();
+
     if (Token::Match(localTypeTok, "%type% <")) {
         if (Token::Match(tok, "const_cast|dynamic_cast|reinterpret_cast|static_cast <"))
             return false;
diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index 0f28cc1fa..6094e8ed4 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -4094,6 +4094,10 @@ static bool setVarIdParseDeclaration(Token** tok, const VariableMap& variableMap
     bool ref = false;
     while (tok2) {
         if (tok2->isName()) {
+            if (Token::simpleMatch(tok2, "alignas (")) {
+                tok2 = tok2->linkAt(1)->next();
+                continue;
+            }
             if (cpp && Token::Match(tok2, "namespace|public|private|protected"))
                 return false;
             if (cpp && Token::simpleMatch(tok2, "decltype (")) {
@@ -5364,8 +5368,6 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])
     // Remove extra "template" tokens that are not used by cppcheck
     removeExtraTemplateKeywords();
 
-    removeAlignas();
-
     simplifySpaceshipOperator();
 
     // Bail out if code is garbage
@@ -5402,7 +5404,7 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])
     // simplify namespace aliases
     simplifyNamespaceAliases();
 
-    // Remove [[attribute]] and alignas(?)
+    // Remove [[attribute]]
     simplifyCPPAttribute();
 
     // remove __attribute__((?))
@@ -8961,17 +8963,6 @@ void Tokenizer::simplifyCPPAttribute()
     }
 }
 
-void Tokenizer::removeAlignas()
-{
-    if (!isCPP() || mSettings->standards.cpp < Standards::CPP11)
-        return;
-
-    for (Token *tok = list.front(); tok; tok = tok->next()) {
-        if (Token::Match(tok, "[;{}] alignas (") && Token::Match(tok->linkAt(2), ") %name%"))
-            Token::eraseTokens(tok, tok->linkAt(2)->next());
-    }
-}
-
 void Tokenizer::simplifySpaceshipOperator()
 {
     if (isCPP() && mSettings->standards.cpp >= Standards::CPP20) {
diff --git a/lib/tokenize.h b/lib/tokenize.h
index 2ef2ac510..c6ab8dd03 100644
--- a/lib/tokenize.h
+++ b/lib/tokenize.h
@@ -475,9 +475,6 @@ private:
      */
     void simplifyCppcheckAttribute();
 
-    /** Remove alignas */
-    void removeAlignas();
-
     /** Simplify c++20 spaceship operator */
     void simplifySpaceshipOperator();
 
diff --git a/test/testsymboldatabase.cpp b/test/testsymboldatabase.cpp
index 730f6c8b6..44b2d21f9 100644
--- a/test/testsymboldatabase.cpp
+++ b/test/testsymboldatabase.cpp
@@ -160,6 +160,7 @@ private:
         TEST_CASE(variableVolatile);
         TEST_CASE(variableConstexpr);
         TEST_CASE(isVariableDecltype);
+        TEST_CASE(isVariableAlignas);
 
         TEST_CASE(VariableValueType1);
         TEST_CASE(VariableValueType2);
@@ -1475,6 +1476,15 @@ private:
         ASSERT_EQUALS("signed int *", c->valueType()->str());
     }
 
+    void isVariableAlignas() {
+        GET_SYMBOL_DB_C("extern alignas(16) int x;\n"
+                        "alignas(16) int x;\n");
+        ASSERT(db);
+        ASSERT_EQUALS(2, db->scopeList.front().varlist.size());
+        const Variable *x1 = Token::findsimplematch(tokenizer.tokens(), "x")->variable();
+        ASSERT(x1 && Token::simpleMatch(x1->typeStartToken(), "alignas ( 16 ) int x ;"));
+    }
+
     void memberVar1() {
         GET_SYMBOL_DB("struct Foo {\n"
                       "    int x;\n"
diff --git a/test/testvarid.cpp b/test/testvarid.cpp
index e908d1d6e..a08cf582b 100644
--- a/test/testvarid.cpp
+++ b/test/testvarid.cpp
@@ -187,6 +187,7 @@ private:
         TEST_CASE(varid_declInIfCondition);
         TEST_CASE(varid_globalScope);
         TEST_CASE(varid_function_pointer_args);
+        TEST_CASE(varid_alignas);
 
         TEST_CASE(varidclass1);
         TEST_CASE(varidclass2);
@@ -3045,6 +3046,14 @@ private:
         ASSERT_EQUALS("1: void f ( void ( * g@1 ) ( int , IN int ) ) { }\n", tokenize(code3));
     }
 
+    void varid_alignas() {
+        const char code[] = "extern alignas(16) int x;\n"
+                            "alignas(16) int x;";
+        const char expected[] = "1: extern alignas ( 16 ) int x@1 ;\n"
+                                "2: alignas ( 16 ) int x@2 ;\n";
+        ASSERT_EQUALS(expected, tokenize(code, "test.c"));
+    }
+
     void varidclass1() {
         const std::string actual = tokenize(
             "class Fred\n"