Re: Struct declaration and initialization in TREES

[Richard Biener <richard.guenther@gmail.com>]

On December 17, 2019 8:31:00 PM GMT+01:00, Erick Ochoa <erick.ochoa@theobroma-systems.com> wrote:
>Hi,
>
>I'm interested in printing VAR_DECL trees that are of type
>RECORD_TYPE. I am using the function print_generic_decl
>for debugging and found this interesting behaviour.
>
>When I do initialization of structs using the following
>syntax:
>
>```
>struct aStruct { _Bool e; int a; char b; float c; double d; _Bool f;
>long h;};
>struct aStruct astruct = { .e = 0, .a = 1, .b = 2, .c = 3.0, .d = 4.0,
>.f = 5, .h = 6 };
>```
>
>print_generic_decl will print the following output:
>
>```
>INTERESTED IN:   static struct aStruct astruct = <<< error >>>;
>```
>
>Am I using the correct API? Is this a limitation of the API?

You need to ask IPA about the static initializer, DECL_INITIAL is adjusted at some point. 

Richard. 

>Would people be interested in me extending this API to print
>out something more useful? I already have some code that
>iterates over fields and prints out names and types. It
>can still use some work though.
>
>However, I understand if this is the intended behaviour.
>Another question (related to the possibility of intended behaviour)
>is: how is struct initialization represented in trees?
>(I.e. will each field be initialized separately or something else
>happens?)
>
>Thanks! I also include the patch in case people want a simple
>working example on how to print declarations.
>
>diff --git a/gcc/Makefile.in b/gcc/Makefile.in
>index 6b857bd..f4f1376 100644
>--- a/gcc/Makefile.in
>+++ b/gcc/Makefile.in
>@@ -1368,6 +1368,7 @@ OBJS = \
> 	incpath.o \
> 	init-regs.o \
> 	internal-fn.o \
>+	ipa-hello-world.o \
> 	ipa-cp.o \
> 	ipa-sra.o \
> 	ipa-devirt.o \
>diff --git a/gcc/common.opt b/gcc/common.opt
>index b4dc31c..304ec9f 100644
>--- a/gcc/common.opt
>+++ b/gcc/common.opt
>@@ -3348,4 +3348,7 @@ fipa-ra
> Common Report Var(flag_ipa_ra) Optimization
> Use caller save register across calls if possible.
> 
>+fipa-typelist
>+Common Report Var(flag_ipa_typelist) TBD
>+
> ; This comment is to ensure we retain the blank line above.
>diff --git a/gcc/ipa-hello-world.c b/gcc/ipa-hello-world.c
>new file mode 100644
>index 0000000..ed4ae11
>--- /dev/null
>+++ b/gcc/ipa-hello-world.c
>@@ -0,0 +1,78 @@
>+#include "config.h"
>+#include "system.h"
>+#include "coretypes.h"
>+#include "backend.h"
>+#include "tree.h"
>+#include "gimple-expr.h"
>+#include "predict.h"
>+#include "alloc-pool.h"
>+#include "tree-pass.h"
>+#include "cgraph.h"
>+#include "diagnostic.h"
>+#include "fold-const.h"
>+#include "gimple-fold.h"
>+#include "symbol-summary.h"
>+#include "tree-vrp.h"
>+#include "ipa-prop.h"
>+#include "tree-pretty-print.h"
>+#include "tree-inline.h"
>+#include "ipa-fnsummary.h"
>+#include "ipa-utils.h"
>+#include "tree-ssa-ccp.h"
>+#include "stringpool.h"
>+#include "attribs.h"
>+
>+
>+static unsigned int
>+iphw_execute()
>+{
>+  if (!dump_file) return 0;
>+  varpool_node *node;
>+  FOR_EACH_VARIABLE(node)
>+  {
>+    gcc_assert(node->decl);
>+    tree decl = node->decl;
>+    gcc_assert(TREE_CODE(decl) == VAR_DECL);
>+
>+    tree curr_type = TREE_TYPE(decl);
>+    gcc_assert(curr_type);
>+
>+    const bool is_struct = TREE_CODE(curr_type) == RECORD_TYPE;
>+    if (is_struct) fprintf(dump_file, "INTERESTED IN: ");
>+    print_generic_decl(dump_file, decl, TDF_DETAILS);
>+    fprintf(dump_file, "\n");
>+  }
>+  return 0;
>+}
>+
>+namespace {
>+const pass_data pass_data_ipa_hello_world =
>+{
>+  SIMPLE_IPA_PASS,
>+  "hello_world",
>+  OPTGROUP_NONE,
>+  TV_NONE,
>+  (PROP_cfg | PROP_ssa),
>+  0,
>+  0,
>+  0,
>+  0,
>+};
>+
>+class pass_ipa_hello_world : public simple_ipa_opt_pass
>+{
>+public:
>+  pass_ipa_hello_world (gcc::context *ctx)
>+    : simple_ipa_opt_pass(pass_data_ipa_hello_world, ctx)
>+  {}
>+
>+  virtual bool gate(function*) { return flag_ipa_typelist; }
>+  virtual unsigned execute (function*) { return iphw_execute(); }
>+};
>+} // anon namespace
>+
>+simple_ipa_opt_pass*
>+make_pass_ipa_hello_world (gcc::context *ctx)
>+{
>+  return new pass_ipa_hello_world (ctx);
>+}
>diff --git a/gcc/passes.def b/gcc/passes.def
>index 798a391..52cd14b 100644
>--- a/gcc/passes.def
>+++ b/gcc/passes.def
>@@ -146,6 +146,7 @@ along with GCC; see the file COPYING3.  If not see
>   NEXT_PASS (pass_ipa_profile);
>   NEXT_PASS (pass_ipa_icf);
>   NEXT_PASS (pass_ipa_devirt);
>+  NEXT_PASS (pass_ipa_hello_world);
>   NEXT_PASS (pass_ipa_cp);
>   NEXT_PASS (pass_ipa_sra);
>   NEXT_PASS (pass_ipa_cdtor_merge);
>diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
>index a987661..915fc69 100644
>--- a/gcc/tree-pass.h
>+++ b/gcc/tree-pass.h
>@@ -498,6 +498,7 @@ extern ipa_opt_pass_d *make_pass_ipa_fn_summary
>(gcc::context *ctxt);
> extern ipa_opt_pass_d *make_pass_ipa_inline (gcc::context *ctxt);
>extern simple_ipa_opt_pass *make_pass_ipa_free_lang_data (gcc::context
>*ctxt);
>extern simple_ipa_opt_pass *make_pass_ipa_free_fn_summary (gcc::context
>*ctxt);
>+extern simple_ipa_opt_pass *make_pass_ipa_hello_world (gcc::context
>*ctxt);
> extern ipa_opt_pass_d *make_pass_ipa_cp (gcc::context *ctxt);
> extern ipa_opt_pass_d *make_pass_ipa_sra (gcc::context *ctxt);
> extern ipa_opt_pass_d *make_pass_ipa_icf (gcc::context *ctxt);