From e717f1b8f84ae6a34f93af2e77daf98ac1a37555 Mon Sep 17 00:00:00 2001 From: Tristan Gingold Date: Sun, 14 May 2017 21:25:46 +0200 Subject: Add comment. --- src/vhdl/translate/trans-chap4.ads | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'src') diff --git a/src/vhdl/translate/trans-chap4.ads b/src/vhdl/translate/trans-chap4.ads index 6ada12419..6bf1afcfe 100644 --- a/src/vhdl/translate/trans-chap4.ads +++ b/src/vhdl/translate/trans-chap4.ads @@ -24,6 +24,26 @@ package Trans.Chap4 is procedure Translate_Subtype_Declaration (Decl : Iir_Subtype_Declaration); procedure Translate_Bool_Type_Declaration (Decl : Iir_Type_Declaration); + -- Translation of declarations occurs in three phases: + -- 1) instance is built by putting objects in a record. + -- 2) subprograms are declared (using instance as the first parameter). + -- 3) subprogram bodies are translated. + -- + -- In some cases (non nested packages), no instance is needed, thus the + -- first phase directly creates objects. + -- Phase 1 and phase 2 could theorically be merged, but the instance + -- pointer is generally created at the end of the phase 1. + -- + -- Phase 2 and phase 3 were merged, but there is at least one case where it + -- is not possible: instantiation of a package INST in package + -- declaration PKG. Subprograms declared in INST must have access to the + -- INST body but also (indirectly) to the PKG body if they call a + -- subprogram declared in PKG (and passed as a subprogram interface). So + -- INST instance is the instance for PKG body. Therefore they must be + -- translated during PKG body translation (that's because INST body appears + -- at the instantiation point instead of the end of PKG body as described + -- in the LRM). + -- Translate declaration DECL, which must not be a subprogram -- specification. procedure Translate_Declaration (Decl : Iir); -- cgit v1.2.3