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| author | Ian Lance Taylor <ian@gcc.gnu.org> | 2018-01-09 23:56:54 +0000 |
|---|---|---|
| committer | Ian Lance Taylor <ian@gcc.gnu.org> | 2018-01-09 23:56:54 +0000 |
| commit | 7117ebbd34484609c88543527496d128014dc0d2 (patch) | |
| tree | 2e759dfa0ae434d9a556946c8dabf9047e2fc444 | |
| parent | 4a59d4472b9a0a4c25c4483a03c71def7cb3aa8c (diff) | |
| download | gcc-7117ebbd34484609c88543527496d128014dc0d2.zip gcc-7117ebbd34484609c88543527496d128014dc0d2.tar.gz gcc-7117ebbd34484609c88543527496d128014dc0d2.tar.bz2 | |
compiler: use temporary variable for stack allocation
Currently, allocation expression that can be allocated on stack
is implemented with __builtin_alloca, which turns into
__morestack_allocate_stack_space, which may call C malloc. This
may be slow. Also if this happens during certain runtime
functions (e.g. write barrier), bad things might happen (when
the escape analysis is enabled for the runtime). Make a temporary
variable on stack for the allocation instead.
Also remove the write barrier in the assignment in building heap
expression when it is stack allocated.
Reviewed-on: https://go-review.googlesource.com/86242
From-SVN: r256412
| -rw-r--r-- | gcc/go/gofrontend/MERGE | 2 | ||||
| -rw-r--r-- | gcc/go/gofrontend/expressions.cc | 17 |
2 files changed, 15 insertions, 4 deletions
diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE index fc2e65d..0c6538d 100644 --- a/gcc/go/gofrontend/MERGE +++ b/gcc/go/gofrontend/MERGE @@ -1,4 +1,4 @@ -bea521d1d8688bea5b14b1ae2a03aec949f48a44 +7ef1b48f63c0a64b83fc049884fb89677e19b2dd The first line of this file holds the git revision number of the last merge done from the gofrontend repository. diff --git a/gcc/go/gofrontend/expressions.cc b/gcc/go/gofrontend/expressions.cc index f4dc8e8..d4a2071 100644 --- a/gcc/go/gofrontend/expressions.cc +++ b/gcc/go/gofrontend/expressions.cc @@ -12387,6 +12387,7 @@ Allocation_expression::do_get_backend(Translate_context* context) { Gogo* gogo = context->gogo(); Location loc = this->location(); + Btype* btype = this->type_->get_backend(gogo); if (this->allocate_on_stack_) { @@ -12397,10 +12398,20 @@ Allocation_expression::do_get_backend(Translate_context* context) go_assert(saw_errors()); return gogo->backend()->error_expression(); } - return gogo->backend()->stack_allocation_expression(size, loc); + Bstatement* decl; + Named_object* fn = context->function(); + go_assert(fn != NULL); + Bfunction* fndecl = fn->func_value()->get_or_make_decl(gogo, fn); + Bexpression* zero = gogo->backend()->zero_expression(btype); + Bvariable* temp = + gogo->backend()->temporary_variable(fndecl, context->bblock(), btype, + zero, true, loc, &decl); + Bexpression* ret = gogo->backend()->var_expression(temp, loc); + ret = gogo->backend()->address_expression(ret, loc); + ret = gogo->backend()->compound_expression(decl, ret, loc); + return ret; } - Btype* btype = this->type_->get_backend(gogo); Bexpression* space = gogo->allocate_memory(this->type_, loc)->get_backend(context); Btype* pbtype = gogo->backend()->pointer_type(btype); @@ -14278,7 +14289,7 @@ Heap_expression::do_get_backend(Translate_context* context) // don't do this in the write barrier pass because in some cases // backend conversion can introduce new Heap_expression values. Bstatement* assn; - if (!etype->has_pointer()) + if (!etype->has_pointer() || this->allocate_on_stack_) { space = gogo->backend()->var_expression(space_temp, loc); Bexpression* ref = |