Fixes for zero-sized allocation #1045

isaachier · 2018-06-03T23:34:32Z

isaachier · 2018-06-03T23:34:58Z

src/analyze.cpp

@@ -1848,10 +1849,10 @@ static void resolve_struct_type(CodeGen *g, TypeTableEntry *struct_type) {
    }

    assert(!struct_type->data.structure.zero_bits_loop_flag);
-    assert(struct_type->data.structure.fields);


Failed assertion.

isaachier · 2018-06-03T23:35:08Z

src/analyze.cpp

    assert(decl_node->type == NodeTypeContainerDecl);

    size_t field_count = struct_type->data.structure.src_field_count;
+    assert(struct_type->data.structure.fields != nullptr || field_count == 0);


Attempted tweak.

isaachier · 2018-06-03T23:35:14Z

src/analyze.cpp

@@ -1964,7 +1965,7 @@ static void resolve_struct_type(CodeGen *g, TypeTableEntry *struct_type) {
        struct_type->di_type = replacement_di_type;
        return;
    }
-    assert(struct_type->di_type);


Failed assertion.

isaachier · 2018-06-03T23:35:22Z

src/analyze.cpp

@@ -1964,7 +1965,7 @@ static void resolve_struct_type(CodeGen *g, TypeTableEntry *struct_type) {
        struct_type->di_type = replacement_di_type;
        return;
    }
-    assert(struct_type->di_type);
+    assert(struct_type->di_type != nullptr || field_count == 0);


Attempted tweak.

isaachier · 2018-06-03T23:35:28Z

src/analyze.cpp

@@ -1976,7 +1977,8 @@ static void resolve_struct_type(CodeGen *g, TypeTableEntry *struct_type) {
    // if you hit this assert then probably this type or a related type didn't
    // get ensure_complete_type called on it before using it with something that
    // requires a complete type
-    assert(LLVMStoreSizeOfType(g->target_data_ref, struct_type->type_ref) > 0);


Failed assertion.

isaachier · 2018-06-03T23:35:36Z

src/analyze.cpp

@@ -1976,7 +1977,8 @@ static void resolve_struct_type(CodeGen *g, TypeTableEntry *struct_type) {
    // if you hit this assert then probably this type or a related type didn't
    // get ensure_complete_type called on it before using it with something that
    // requires a complete type
-    assert(LLVMStoreSizeOfType(g->target_data_ref, struct_type->type_ref) > 0);
+    assert(LLVMStoreSizeOfType(g->target_data_ref, struct_type->type_ref) > 0 ||


Attempted tweak.

isaachier · 2018-06-03T23:36:12Z

src/codegen.cpp

@@ -5922,20 +5922,20 @@ static const uint8_t int_sizes_in_bits[] = {
 };

 struct CIntTypeInfo {


Padding fix discussed in #993.

isaachier · 2018-06-03T23:36:44Z

src/util.hpp

@@ -73,6 +76,9 @@ ATTRIBUTE_RETURNS_NOALIAS static inline T *allocate_nonzero(size_t count) {

 template<typename T>
 ATTRIBUTE_RETURNS_NOALIAS static inline T *allocate(size_t count) {
+    if (count == 0) {


Makes behavior for zero sized allocation portable.

isaachier · 2018-06-03T23:37:11Z

src/util.hpp

-    T *ptr = reinterpret_cast<T*>(realloc(old, new_count * sizeof(T)));
-    if (!ptr)
-        zig_panic("allocation failed");
+static inline T *reallocate(T *old, size_t old_count, size_t new_count) {


Implement reallocate using reallocate_nonzero to avoid code duplication.

isaachier · 2018-06-03T23:37:41Z

src/ir.cpp

@@ -7647,7 +7647,7 @@ static TypeTableEntry *get_error_set_intersection(IrAnalyze *ira, TypeTableEntry
        assert(errors[error_entry->value] == nullptr);
        errors[error_entry->value] = error_entry;
    }
-    ZigList<ErrorTableEntry *> intersection_list = {};
+    ZigList<ErrorTableEntry *> intersection_list = {0};


You will see this in a few places. ZigList needs to be initialized in order to guarantee the members are zeroed.

Can you cite a source showing that {0} is necessary and {} is not sufficient?

Actually you are right: https://stackoverflow.com/a/1069634/1930331. Maybe I'm thinking about C, but C++ will work.

Fixes for zero-sized allocation

6e248bb

isaachier commented Jun 3, 2018

View reviewed changes

andrewrk closed this in 32e0dfd Jun 4, 2018

isaachier deleted the minor-cpp-improvements branch June 4, 2018 20:42

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Fixes for zero-sized allocation #1045

Fixes for zero-sized allocation #1045

isaachier commented Jun 3, 2018

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isaachier Jun 3, 2018

isaachier Jun 3, 2018

isaachier Jun 3, 2018

andrewrk Jun 4, 2018

isaachier Jun 4, 2018

		@@ -5922,20 +5922,20 @@ static const uint8_t int_sizes_in_bits[] = {
		};

		struct CIntTypeInfo {

Fixes for zero-sized allocation #1045

Fixes for zero-sized allocation #1045

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isaachier commented Jun 3, 2018

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