This patch fixes a memory leak in the pass manager. In the existing code,
the m_name_to_pass_map is allocated in pass_manager::register_pass_name, but
never deallocated. This is fixed by adding a deletion in
pass_manager::~pass_manager. Moreover the string keys in m_name_to_pass_map are
all dynamically allocated. To free them, this patch adds a new hash trait for
string hashes that are to be freed when the corresponding hash entry is removed.
This fix is particularly relevant for using GCC as a library through libgccjit.
The memory leak also occurs when libgccjit is instructed to use an external
driver.
Before the patch, compiling the hello world example of libgccjit with
the external driver under Valgrind shows a loss of 12,611 (48 direct)
bytes. After the patch, no memory leaks are reported anymore.
(Memory leaks occurring when using the internal driver are mostly in
the driver code in gcc/gcc.c and have to be fixed separately.)
The patch has been tested by fully bootstrapping the compiler with the
frontends C, C++, Fortran, LTO, ObjC, JIT and running the test suite
under a x86_64-pc-linux-gnu host.
gcc/ChangeLog:
PR jit/63854
* hash-traits.h (struct typed_const_free_remove): New.
(struct free_string_hash): New.
* pass_manager.h: Use free_string_hash.
* passes.c (pass_manager::register_pass_name): Use free_string_hash.
(pass_manager::~pass_manager): Delete allocated m_name_to_pass_map.
---
gcc/hash-traits.h | 17 +++++++++++++++++
gcc/pass_manager.h | 3 +--
gcc/passes.c | 5 +++--
3 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/gcc/hash-traits.h b/gcc/hash-traits.h
index 6f0373ec27f..1c08d6874ab 100644
--- a/gcc/hash-traits.h
+++ b/gcc/hash-traits.h
@@ -28,6 +28,11 @@ struct typed_free_remove
static inline void remove (Type *p);
};
+template <typename Type>
+struct typed_const_free_remove
+{
+ static inline void remove (const Type *p);
+};
/* Remove with free. */
@@ -38,6 +43,13 @@ typed_free_remove <Type>::remove (Type *p)
free (p);
}
+template <typename Type>
+inline void
+typed_const_free_remove <Type>::remove (const Type *p)
+{
+ free (const_cast <Type *> (p));
+}
+
/* Helpful type for removing with delete. */
template <typename Type>
@@ -305,6 +317,11 @@ struct ggc_ptr_hash : pointer_hash <T>, ggc_remove <T *>
{};
template <typename T>
struct ggc_cache_ptr_hash : pointer_hash <T>, ggc_cache_remove <T *> {};
+/* Traits for string elements that should be freed when an element is
+ deleted. */
+
+struct free_string_hash : string_hash, typed_const_free_remove <char> {};
+
/* Traits for string elements that should not be freed when an element
is deleted. */
diff --git a/gcc/pass_manager.h b/gcc/pass_manager.h
index aaf72cf6803..f5615e1fda8 100644
--- a/gcc/pass_manager.h
+++ b/gcc/pass_manager.h
@@ -106,7 +106,7 @@ private:
private:
context *m_ctxt;
- hash_map<nofree_string_hash, opt_pass *> *m_name_to_pass_map;
+ hash_map<free_string_hash, opt_pass *> *m_name_to_pass_map;
/* References to all of the individual passes.
These fields are generated via macro expansion.
@@ -146,4 +146,3 @@ private:
} // namespace gcc
#endif /* ! GCC_PASS_MANAGER_H */
-
diff --git a/gcc/passes.c b/gcc/passes.c
index 4bea6ae5b6a..0c70ece5321 100644
--- a/gcc/passes.c
+++ b/gcc/passes.c
@@ -903,7 +903,7 @@ void
pass_manager::register_pass_name (opt_pass *pass, const char *name)
{
if (!m_name_to_pass_map)
- m_name_to_pass_map = new hash_map<nofree_string_hash, opt_pass *> (256);
+ m_name_to_pass_map = new hash_map<free_string_hash, opt_pass *> (256);
if (m_name_to_pass_map->get (name))
return; /* Ignore plugin passes. */
@@ -1674,6 +1674,7 @@ pass_manager::~pass_manager ()
GCC_PASS_LISTS
#undef DEF_PASS_LIST
+ delete m_name_to_pass_map;
}
/* If we are in IPA mode (i.e., current_function_decl is NULL), call
@@ -1943,7 +1944,7 @@ pass_manager::dump_profile_report () const
" |in count |out prob "
"|in count |out prob "
"|size |time |\n");
-
+
for (int i = 1; i < passes_by_id_size; i++)
if (profile_record[i].run)
{
--
2.32.0
