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Cleanup code around JERRY_UNREACHABLEs (#2342)

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`JERRY_UNREACHABLE`s often signal code structure that could be
improved: they can usually either be rewritten to `JERRY_ASSERT`s
or eliminated by restructuring loops, `if`s or `#if`s. Roughly,
the only valid occurences are in default cases of `switch`es. And
even they can often be merged into non-default cases.

Moreover, it is dangerous to write meaningful code after
`JERRY_UNREACHABLE` because it pretends as if there was a way to
recover from an impossible situation.

This patch rewrites/eliminates `JERRY_UNREACHABLE`s where possible
and removes misleading code from after them.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu
This commit is contained in:
Akos Kiss
2018-05-25 07:27:30 +02:00
committed by GitHub
parent acb3e71436
commit 4779451284
24 changed files with 168 additions and 256 deletions
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jerry-core/jmem/jmem-poolman.c
+16 -9
View File
@@ -85,8 +85,13 @@ jmem_pools_alloc (size_t size) /**< size of the chunk */
jmem_run_free_unused_memory_callbacks (JMEM_FREE_UNUSED_MEMORY_SEVERITY_HIGH);
#endif /* JMEM_GC_BEFORE_EACH_ALLOC */
#ifdef JERRY_CPOINTER_32_BIT
if (size <= 8)
{
#else /* !JERRY_CPOINTER_32_BIT */
JERRY_ASSERT (size <= 8);
#endif /* JERRY_CPOINTER_32_BIT */
if (JERRY_CONTEXT (jmem_free_8_byte_chunk_p) != NULL)
{
const jmem_pools_chunk_t *const chunk_p = JERRY_CONTEXT (jmem_free_8_byte_chunk_p);
@@ -103,9 +108,10 @@ jmem_pools_alloc (size_t size) /**< size of the chunk */
{
return (void *) jmem_heap_alloc_block (8);
}
}
#ifdef JERRY_CPOINTER_32_BIT
}
JERRY_ASSERT (size <= 16);
if (JERRY_CONTEXT (jmem_free_16_byte_chunk_p) != NULL)
@@ -124,10 +130,7 @@ jmem_pools_alloc (size_t size) /**< size of the chunk */
{
return (void *) jmem_heap_alloc_block (16);
}
#else /* !JERRY_CPOINTER_32_BIT */
JERRY_UNREACHABLE ();
return NULL;
#endif
#endif /* JERRY_CPOINTER_32_BIT */
} /* jmem_pools_alloc */
/**
@@ -143,22 +146,26 @@ jmem_pools_free (void *chunk_p, /**< pointer to the chunk */
VALGRIND_DEFINED_SPACE (chunk_to_free_p, size);
#ifdef JERRY_CPOINTER_32_BIT
if (size <= 8)
{
#else /* !JERRY_CPOINTER_32_BIT */
JERRY_ASSERT (size <= 8);
#endif /* JERRY_CPOINTER_32_BIT */
chunk_to_free_p->next_p = JERRY_CONTEXT (jmem_free_8_byte_chunk_p);
JERRY_CONTEXT (jmem_free_8_byte_chunk_p) = chunk_to_free_p;
#ifdef JERRY_CPOINTER_32_BIT
}
else
{
#ifdef JERRY_CPOINTER_32_BIT
JERRY_ASSERT (size <= 16);
chunk_to_free_p->next_p = JERRY_CONTEXT (jmem_free_16_byte_chunk_p);
JERRY_CONTEXT (jmem_free_16_byte_chunk_p) = chunk_to_free_p;
#else /* !JERRY_CPOINTER_32_BIT */
JERRY_UNREACHABLE ();
#endif /* JERRY_CPOINTER_32_BIT */
}
#endif /* JERRY_CPOINTER_32_BIT */
VALGRIND_NOACCESS_SPACE (chunk_to_free_p, size);
} /* jmem_pools_free */