Merge pull request #661 from andreasfertig/fixCfrontVtable

Fixed vtable initialization.
andreasfertig · Jul 19, 2024 · 4f78c7d · 4f78c7d
2 parents 243312b + 5ecb45f
commit 4f78c7d
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Showing 6 changed files with 224 additions and 16 deletions.
diff --git a/CfrontCodeGenerator.cpp b/CfrontCodeGenerator.cpp
@@ -438,6 +438,27 @@ void CfrontCodeGenerator::InsertArg(const CXXOperatorCallExpr* stmt)
 }
 //-----------------------------------------------------------------------------
 
+static void InsertVtblPtr(const CXXMethodDecl* stmt, const CXXRecordDecl* cur, StmtsContainer& bodyStmts)
+{
+    if(cur->isPolymorphic() and (0 == cur->getNumBases())) {
+        auto* fieldDecl     = CfrontCodeGenerator::VtableData().VtblPtrField(cur);
+        auto* lhsMemberExpr = AccessMember(kwInternalThis, fieldDecl, Ptr(GetRecordDeclType(cur)));
+
+        // struct __mptr *__ptbl_vec__c___src_C_[]
+        auto* vtablAr = CfrontCodeGenerator::VtableData().VtblArrayVar(1);
+        auto* vtblArrayPos =
+            ArraySubscript(mkDeclRefExpr(vtablAr), GetGlobalVtablePos(stmt->getParent(), cur), fieldDecl->getType());
+
+        bodyStmts.AddBodyStmts(Assign(lhsMemberExpr, fieldDecl, vtblArrayPos));
+
+    } else if(cur->isPolymorphic() and (0 < cur->getNumBases()) and (cur != stmt->getParent())) {
+        for(const auto& base : cur->bases()) {
+            InsertVtblPtr(stmt, base.getType()->getAsCXXRecordDecl(), bodyStmts);
+        }
+    }
+}
+//-----------------------------------------------------------------------------
+
 void CfrontCodeGenerator::InsertCXXMethodDecl(const CXXMethodDecl* stmt, SkipBody)
 {
     OutputFormatHelper initOutputFormatHelper{};
@@ -565,26 +586,12 @@ void CfrontCodeGenerator::InsertCXXMethodDecl(const CXXMethodDecl* stmt, SkipBod
                 insertFields(baseType->getAsRecordDecl());
             }
 
-            auto insertVtblPtr = [&](const CXXRecordDecl* cur) {
-                if(cur->isPolymorphic() and (0 == cur->getNumBases())) {
-                    auto* fieldDecl     = VtableData().VtblPtrField(cur);
-                    auto* lhsMemberExpr = AccessMember(kwInternalThis, fieldDecl, Ptr(GetRecordDeclType(cur)));
-
-                    // struct __mptr *__ptbl_vec__c___src_C_[]
-                    auto* vtablAr      = VtableData().VtblArrayVar(1);
-                    auto* vtblArrayPos = ArraySubscript(
-                        mkDeclRefExpr(vtablAr), GetGlobalVtablePos(stmt->getParent(), cur), fieldDecl->getType());
-
-                    bodyStmts.AddBodyStmts(Assign(lhsMemberExpr, fieldDecl, vtblArrayPos));
-                }
-            };
-
             // insert our vtable pointer
-            insertVtblPtr(stmt->getParent());
+            InsertVtblPtr(stmt, stmt->getParent(), bodyStmts);
 
             // in case of multi inheritance insert additional vtable pointers
             for(const auto& base : parent->bases()) {
-                insertVtblPtr(base.getType()->getAsCXXRecordDecl());
+                InsertVtblPtr(stmt, base.getType()->getAsCXXRecordDecl(), bodyStmts);
             }
 
             // insert own fields

diff --git a/tests/EduCfrontTest7.expect b/tests/EduCfrontTest7.expect
@@ -172,6 +172,7 @@ inline Derived * Constructor_Derived(Derived * __this)
   Constructor_Type(&__this->mY, 5);
   Constructor_BaseThird((BaseThird *)__this);
   Constructor_Type(&__this->mZ, 5);
+  __this->__vptrBase = __vtbl_array[3];
   __this->__vptrBaseThird = __vtbl_array[4];
   /* dt // trivial type, maybe uninitialized */
   __this->g = 4;

diff --git a/tests/EduCfrontVtable3Test.expect b/tests/EduCfrontVtable3Test.expect
@@ -126,6 +126,7 @@ inline C * Constructor_C(C * __this)
 {
   Constructor_B((B *)__this);
   __this->mX = 5;
+  __this->__vptrA = __vtbl_array[2];
   __this->mB = 8;
   return __this;
 }

diff --git a/tests/EduCfrontVtable4Test.expect b/tests/EduCfrontVtable4Test.expect
@@ -135,6 +135,7 @@ inline C * Constructor_C(C * __this)
 {
   Constructor_B((B *)__this);
   __this->mX = 5;
+  __this->__vptrA = __vtbl_array[2];
   __this->mB = 8;
   return __this;
 }

diff --git a/tests/EduCfrontVtable7Test.cpp b/tests/EduCfrontVtable7Test.cpp
@@ -0,0 +1,29 @@
+// cmdlineinsights:-edu-show-cfront
+
+#include <cstdio>
+
+struct Fruit {
+  double md;
+  virtual ~Fruit() { puts("~Fruit"); }
+  virtual void Fun() { puts("Fruit's Fun"); }
+};
+
+struct Apple : Fruit {
+  int  mX{5};
+  void Fun() override { printf("Apple's Fun: %d\n", mX); }
+};
+
+struct PinkLady : Apple {
+  int  mApple{8};
+  void Fun() override { printf("Pink Ladies Fun: %d\n", mApple); }
+};
+
+int main()
+{
+  PinkLady delicious{};
+  delicious.Fun();
+
+  Fruit* f{static_cast<Fruit*>(&delicious)};
+  f->Fun();
+}
+
diff --git a/tests/EduCfrontVtable7Test.expect b/tests/EduCfrontVtable7Test.expect
@@ -0,0 +1,169 @@
+/*************************************************************************************
+ * NOTE: This an educational hand-rolled transformation. Things can be incorrect or  *
+ * buggy.                                                                            *
+ *************************************************************************************/
+void __cxa_start(void);
+void __cxa_atexit(void);
+typedef int (*__vptp)();
+
+struct __mptr
+{
+    short  d;
+    short  i;
+    __vptp f;
+};
+
+extern struct __mptr* __vtbl_array[];
+
+
+#include <cstdio>
+
+typedef struct Fruit
+{
+  __mptr * __vptrFruit;
+  double md;
+} Fruit;
+
+inline void Destructor_Fruit(Fruit * __this)
+{
+  puts("~Fruit");
+}
+
+inline void FunFruit(Fruit * __this)
+{
+  puts("Fruit's Fun");
+}
+
+inline Fruit * operatorEqual(Fruit * __this, const Fruit * __rhs)
+{
+  __this->md = __rhs->md;
+  return __this;
+}
+
+inline Fruit * Constructor_Fruit(Fruit * __this)
+{
+  __this->__vptrFruit = __vtbl_array[0];
+  return __this;
+}
+
+
+typedef struct Apple
+{
+  __mptr * __vptrFruit;
+  double md;
+  int mX;
+} Apple;
+
+inline void FunApple(Apple * __this)
+{
+  printf("Apple's Fun: %d\n", __this->mX);
+}
+
+inline Apple * operatorEqual(Apple * __this, const Apple * __rhs)
+{
+  __this->md = __rhs->md;
+  operatorEqual((Fruit *)__this, (Fruit *)__rhs);
+  __this->mX = __rhs->mX;
+  return __this;
+}
+
+inline Apple * operatorEqual(Apple * __this, Apple * __rhs)
+{
+  __this->md = __rhs->md;
+  operatorEqual((Fruit *)__this, (Fruit *)__rhs);
+  __this->mX = __rhs->mX;
+  return __this;
+}
+
+inline void Destructor_Apple(Apple * __this)
+{
+  Destructor_Fruit((Fruit *)__this);
+}
+
+inline Apple * Constructor_Apple(Apple * __this)
+{
+  Constructor_Fruit((Fruit *)__this);
+  __this->__vptrFruit = __vtbl_array[1];
+  __this->mX = 5;
+  return __this;
+}
+
+
+typedef struct PinkLady
+{
+  __mptr * __vptrFruit;
+  double md;
+  int mX;
+  int mApple;
+} PinkLady;
+
+inline void FunPinkLady(PinkLady * __this)
+{
+  printf("Pink Ladies Fun: %d\n", __this->mApple);
+}
+
+inline PinkLady * operatorEqual(PinkLady * __this, const PinkLady * __rhs)
+{
+  __this->mX = __rhs->mX;
+  operatorEqual((Apple *)__this, (Apple *)__rhs);
+  __this->mApple = __rhs->mApple;
+  return __this;
+}
+
+inline PinkLady * operatorEqual(PinkLady * __this, PinkLady * __rhs)
+{
+  __this->mX = __rhs->mX;
+  operatorEqual((Apple *)__this, (Apple *)__rhs);
+  __this->mApple = __rhs->mApple;
+  return __this;
+}
+
+inline void Destructor_PinkLady(PinkLady * __this)
+{
+  Destructor_Apple((Apple *)__this);
+}
+
+inline PinkLady * Constructor_PinkLady(PinkLady * __this)
+{
+  Constructor_Apple((Apple *)__this);
+  __this->mX = 5;
+  __this->__vptrFruit = __vtbl_array[2];
+  __this->mApple = 8;
+  return __this;
+}
+
+
+int __main(void)
+{
+  PinkLady delicious;
+  Constructor_PinkLady((PinkLady *)&delicious);
+  (*((void (*)(PinkLady *))((&delicious)->__vptrFruit[0]).f))((((PinkLady *)(char *)(&delicious)) + ((&delicious)->__vptrFruit[0]).d));
+  Fruit * f = (Fruit *)&delicious;
+  (*((void (*)(Fruit *))((f)->__vptrFruit[0]).f))((((Fruit *)(char *)(f)) + ((f)->__vptrFruit[0]).d));
+  return 0;
+  (*((void (*)(PinkLady *))((&delicious)->__vptrFruit[0]).f))((((PinkLady *)(char *)(&delicious)) + ((&delicious)->__vptrFruit[0]).d));
+}
+
+int main(void)
+{
+  __cxa_start();
+  int ret = __main();
+  __cxa_atexit();
+  return ret;
+  /* ret // lifetime ends here */
+}
+
+__mptr __vtbl_Fruit[2] = {{0, 0, (__vptp)Destructor_Fruit}, {0, 0, (__vptp)FunFruit}};
+__mptr __vtbl_Apple[2] = {{0, 0, (__vptp)Destructor_Apple}, {0, 0, (__vptp)FunApple}};
+__mptr __vtbl_PinkLady[2] = {{0, 0, (__vptp)Destructor_PinkLady}, {0, 0, (__vptp)FunPinkLady}};
+
+__mptr * __vtbl_array[3] = {__vtbl_Fruit, __vtbl_Apple, __vtbl_PinkLady};
+
+void __cxa_start(void)
+{
+}
+
+void __cxa_atexit(void)
+{
+}
+