From f62a6ed01730a803f6a993726f86425294049487 Mon Sep 17 00:00:00 2001 From: Nicolai Haehnle Date: Mon, 4 Jun 2018 14:26:12 +0000 Subject: [PATCH] TableGen: some LangRef doc fixes Summary: Change-Id: I1442e2daa09cab727a01d8c31893b50e644a5cd3 Reviewers: tra, simon_tatham, craig.topper Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D47530 Change-Id: I397655dd18b7ff978c1affa3174740d9c1a82594 llvm-svn: 333901 --- docs/TableGen/LangIntro.rst | 21 +++++++++++++++++++-- docs/TableGen/LangRef.rst | 15 ++++++++++++--- 2 files changed, 31 insertions(+), 5 deletions(-) diff --git a/docs/TableGen/LangIntro.rst b/docs/TableGen/LangIntro.rst index b77dad07bf0..ea46550ffc0 100644 --- a/docs/TableGen/LangIntro.rst +++ b/docs/TableGen/LangIntro.rst @@ -152,8 +152,8 @@ supported include: ``foreach = [ ] in `` Replicate or , replacing instances of with each value in . is scoped at the level of the ``foreach`` loop and must - not conflict with any other object introduced in or . Currently - only ``def``\s are expanded within . + not conflict with any other object introduced in or . Only + ``def``\s and ``defm``\s are expanded within . ``foreach = 0-15 in ...`` @@ -348,6 +348,23 @@ In this case, the ``Z`` definition will have a zero value for its ``V`` value, despite the fact that it derives (indirectly) from the ``C`` class, because the ``D`` class overrode its value. +References between variables in a record are substituted late, which gives +``let`` expressions unusual power. Consider this admittedly silly example: + +.. code-block:: text + + class A { + int Y = x; + int Yplus1 = !add(Y, 1); + int xplus1 = !add(x, 1); + } + def Z : A<5> { + let Y = 10; + } + +The value of ``Z.xplus1`` will be 6, but the value of ``Z.Yplus1`` is 11. Use +this power wisely. + .. _template arguments: Class template arguments diff --git a/docs/TableGen/LangRef.rst b/docs/TableGen/LangRef.rst index d31f7f36c80..439d646034a 100644 --- a/docs/TableGen/LangRef.rst +++ b/docs/TableGen/LangRef.rst @@ -229,15 +229,17 @@ of: int Baz = Bar; } + Values defined in superclasses can be accessed the same way. + * a template arg of a ``class``, such as the use of ``Bar`` in:: class Foo { int Baz = Bar; } -* value local to a ``multiclass``, such as the use of ``Bar`` in:: +* value local to a ``class``, such as the use of ``Bar`` in:: - multiclass Foo { + class Foo { int Bar = 5; int Baz = Bar; } @@ -245,9 +247,16 @@ of: * a template arg to a ``multiclass``, such as the use of ``Bar`` in:: multiclass Foo { - int Baz = Bar; + def : SomeClass; } +* the iteration variable of a ``foreach``, such as the use of ``i`` in:: + + foreach i = 0-5 in + def Foo#i; + +* a variable defined by ``defset`` + * the implicit template argument ``NAME`` in a ``class`` or ``multiclass`` .. productionlist::