Summary:
The new rules are straightforward. The main rules to keep in mind
are:
1. NAME is an implicit template argument of class and multiclass,
and will be substituted by the name of the instantiating def/defm.
2. The name of a def/defm in a multiclass must contain a reference
to NAME. If such a reference is not present, it is automatically
prepended.
And for some additional subtleties, consider these:
3. defm with no name generates a unique name but has no special
behavior otherwise.
4. def with no name generates an anonymous record, whose name is
unique but undefined. In particular, the name won't contain a
reference to NAME.
Keeping rules 1&2 in mind should allow a predictable behavior of
name resolution that is simple to follow.
The old "rules" were rather surprising: sometimes (but not always),
NAME would correspond to the name of the toplevel defm. They were
also plain bonkers when you pushed them to their limits, as the old
version of the TableGen test case shows.
Having NAME correspond to the name of the toplevel defm introduces
"spooky action at a distance" and breaks composability:
refactoring the upper layers of a hierarchy of nested multiclass
instantiations can cause unexpected breakage by changing the value
of NAME at a lower level of the hierarchy. The new rules don't
suffer from this problem.
Some existing .td files have to be adjusted because they ended up
depending on the details of the old implementation.
Change-Id: I694095231565b30f563e6fd0417b41ee01a12589
Reviewers: tra, simon_tatham, craig.topper, MartinO, arsenm, javed.absar
Subscribers: wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D47430
llvm-svn: 333900
Summary:
In the course of writing an experimental ANTLR grammar based on this
document, I found three errors in the documented BNF:
SimpleValues of dag type are allowed to have no operands at all after
the initial DagArg specifying the operator. For example, the value
(outs) is extremely common in backends; an example in the test suite
is test/TableGen/AsmVariant.td line 30. But the BNF doesn't allow
DagArgList to expand to the empty string (it must contain at least one
DagArg), and therefore the DagArgList specifying the operands in the
dag-shaped production for SimpleValue should be optional.
In the production for BodyItem with a 'let' and an optional RangeList,
the RangeList should have braces around it if it's present, matching
code such as "let E{7-0} = ..." on test/TableGen/BitsInit.td line 42.
Those braces aren't included in the RangeList nonterminal itself, so
instead they need to be part of the optional segment of the BodyItem
production.
Finally, the identifier after 'defm' should be optional. Again, this
is very common in the real back end .td files; an example in the test
suite is in test/TableGen/defmclass.td line 49.
Reviewers: rengolin, nhaehnle, stoklund
Reviewed By: nhaehnle
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45818
llvm-svn: 330570
This allows constructing DAG nodes with programmatically determined
names, and can simplify constructing DAG nodes in other cases as
well.
Also, add documentation and some very simple tests for the already
existing !con.
Change-Id: Ida61cd82e99752548d7109ce8da34d29da56a5f7
Differential revision: https://reviews.llvm.org/D44110
llvm-svn: 327492
Allows capturing a list of concrete instantiated defs.
This can be combined with foreach to create parallel sets of def
instantiations with less repetition in the source. This purpose is
largely also served by multiclasses, but in some cases multiclasses
can't be used.
The motivating example for this change is having a large set of
intrinsics, which are generated from the IntrinsicsBackend.td file
included by Intrinsics.td, and a corresponding set of instruction
selection patterns, which are generated via the backend's .td files.
Multiclasses cannot be used to eliminate the redundancy in this case,
because a multiclass cannot span both LLVM's common .td files and
the backend .td files at the same time.
Change-Id: I879e35042dceea542a5e6776fad23c5e0e69e76b
Differential revision: https://reviews.llvm.org/D44109
llvm-svn: 327121
The changes to FieldInit are required to make field references (Def.field)
work inside a ForeachDeclaration: previously, Def.field wasn't resolved
immediately when Def was already a fully resolved DefInit.
Change-Id: I9875baec2fc5aac8c2b249e45b9cf18c65ae699b
llvm-svn: 327120
Summary:
Returns the size of a list. I have found this to be rather useful in some
development for the AMDGPU backend where we could simplify our .td files
by concatenating list<LLVMType> for complex intrinsics. Doing so requires
us to compute the position argument for LLVMMatchType.
Basically, the usage is in a pattern that looks somewhat like this:
list<LLVMType> argtypes =
!listconcat(base,
[llvm_any_ty, LLVMMatchType<!size(base)>]);
Change-Id: I360a0b000fd488d18bea412228230fd93722bd2c
Reviewers: arsenm, craig.topper, tra, MartinO
Subscribers: wdng, llvm-commits, tpr
Differential Revision: https://reviews.llvm.org/D43553
llvm-svn: 325883
Summary:
It concatenates two or more lists. In addition to the !strconcat semantics
the lists must have the same element type.
My overall aim is to make it easy to append to Instruction.Predicates
rather than override it. This can be done by concatenating lists passed as
arguments, or by concatenating lists passed in additional fields.
Reviewers: dsanders
Reviewed By: dsanders
Subscribers: hfinkel, llvm-commits
Differential Revision: http://reviews.llvm.org/D3506
llvm-svn: 208183
Making the new TableGen documentation official and marking the old file as
"Moved". Also, reverting the original LangRef as the normative formal
description of the language, while keeping the "new" LangRef as LangIntro
for the less inlcined to reading language grammars.
We should remove TableGenFundamentals.rst one day, but for now, just a
warning that it moved will have to do, while we make sure there are no more
links to it from elsewhere.
llvm-svn: 205289
This is mainly a movement of content around to give place to new content
allowing different people to add bits to it in the right place. There is some
new content, but mostly to fill the gaps left by text movement.
I'm dropping the old syntax documentation as it has the problem of being
quickly outdated by changes and largely unnecessary to people not involved
in creating the language, but using it, which is the whole point of the
documentation.
llvm-svn: 204351
They're called code fragments, but they are really multiline string
literals. Just spotted this usage in a patch by Aaron using "code
fragments" for holding documentation text. I remember someone bemoaning
the lack of multiline string literals in TableGen, so I'm explicitly
documenting that code fragments are multiline string literals.
Let it be known that any use case needing multiline string literals in
TableGen (such as descriptions of options, or whatnot) can use use
code fragments (instead of C-style string concatenation or exceedingly
long lines). E.g.
class Bar<int n>;
class Baz<int n>;
class Doc<string desc> {
string Desc = desc;
}
def Foo : Bar<1>, Baz<3>, Doc<[{
This Foo is a Bar, and also a Baz. It can take 3 values:
* Qux
* Quux
* Quuux
}]>;
llvm-svn: 201033
DAG arguments can optionally be named:
(dag node, node:$name)
With this change, the node is also optional:
(dag node, node:$name, $name)
The missing node is treated as an UnsetInit, so the above is equivalent
to:
(dag node, node:$name, ?:$name)
This syntax is useful in output patterns where we currently require the
types of variables to be repeated:
def : Pat<(subc i32:$b, i32:$c), (SUBCCrr i32:$b, i32:$c)>;
This is preferable:
def : Pat<(subc i32:$b, i32:$c), (SUBCCrr $b, $c)>;
llvm-svn: 177843
My "excuse" for not refactoring the grammar here is to not diverge too
far from the grammar in the comments of TGParser.cpp, since I'm not
taking on the quest of majorly refactoring TGParser.cpp at the moment.
One benefit of doing this is that Ideas for refactoring and clarifying
the grammar in this document should translate almost immediately to
beneficial refactorings that can be made to TGParser.cpp.
llvm-svn: 174144
