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libexpr: Rely on Boehm returning zeroed memory in EvalState::allocEnv()

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Boehm guarantees that memory returned by GC_malloc() is zeroed, so take
advantage of that.
This commit is contained in:
Tuomas Tynkkynen 2018-02-13 05:00:17 +02:00
parent b8bed7da14
commit 0845cdf944
2 changed files with 5 additions and 5 deletions
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3
src/libexpr/attr-set.cc
View file

@ -7,13 +7,14 @@
namespace nix { namespace nix {
/* Note: Various places expect the allocated memory to be zeroed. */
static void * allocBytes(size_t n) static void * allocBytes(size_t n)
{ {
void * p; void * p;
#if HAVE_BOEHMGC #if HAVE_BOEHMGC
p = GC_malloc(n); p = GC_malloc(n);
#else #else
p = malloc(n); p = calloc(n, 1);
#endif #endif
if (!p) throw std::bad_alloc(); if (!p) throw std::bad_alloc();
return p; return p;

7
src/libexpr/eval.cc
View file

@ -43,13 +43,14 @@ static char * dupString(const char * s)
} }
/* Note: Various places expect the allocated memory to be zeroed. */
static void * allocBytes(size_t n) static void * allocBytes(size_t n)
{ {
void * p; void * p;
#if HAVE_BOEHMGC #if HAVE_BOEHMGC
p = GC_malloc(n); p = GC_malloc(n);
#else #else
p = malloc(n); p = calloc(n, 1);
#endif #endif
if (!p) throw std::bad_alloc(); if (!p) throw std::bad_alloc();
return p; return p;
@ -582,9 +583,7 @@ Env & EvalState::allocEnv(unsigned int size)
Env * env = (Env *) allocBytes(sizeof(Env) + size * sizeof(Value *)); Env * env = (Env *) allocBytes(sizeof(Env) + size * sizeof(Value *));
env->size = size; env->size = size;
/* Clear the values because maybeThunk() and lookupVar fromWith expect this. */ /* We assume that env->values has been cleared by the allocator; maybeThunk() and lookupVar fromWith expect this. */
for (unsigned i = 0; i < size; ++i)
env->values[i] = 0;
return *env; return *env;
} }