20 Sep
2004
20 Sep
'04
8:35 p.m.
This patch reveals the lack of nolimips in immediate checking:
li $t0, 0x10001
is invalid since 0x10001 does not fit in 16bits. In these cases,
the assembler should output:
lui $t0, 0x1
ori $t0, $t0, 0x10000
... The worst is that this remark is valid for every immediate
instructions (addi, ori, andi, etc.)
Index: ChangeLog
from Benoît Perrot <benoit(a)lrde.epita.fr>
Li is not a native instruction
* dev/nolimips.xml, src/int/program_builder.cc:
Make `li' a pseudo instruction for `addiu'.
* src/vm/cpu.hh, src/vm/cpu.cc:
Remove emulation of `li'.
Index: src/vm/cpu.hh
--- src/vm/cpu.hh (revision 124)
+++ src/vm/cpu.hh (revision 125)
@@ -195,7 +195,6 @@
virtual void visit(const inst::Lb& lb);
virtual void visit(const inst::Lbu& Lbu);
virtual void visit(const inst::Lw& lw);
- virtual void visit(const inst::Li& li);
virtual void visit(const inst::Sb& sb);
virtual void visit(const inst::Sw& sw);
Index: src/vm/cpu.cc
--- src/vm/cpu.cc (revision 124)
+++ src/vm/cpu.cc (revision 125)
@@ -365,12 +365,6 @@
// Move instructions
// --------------------------------------------------------------------------
- void
- Cpu::visit(const inst::Li& li)
- {
- set_register(li.get_dest (), li.get_imm ());
- }
-
// Store
void
Cpu::visit(const inst::Sb& sb)
Index: src/inst/program_builder.cc
--- src/inst/program_builder.cc (revision 124)
+++ src/inst/program_builder.cc (revision 125)
@@ -50,7 +50,8 @@
{
// Warning: is not implemented in as for mips, check why.
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Mul(*dest, *src1, Register(Register::general, Cpu::at)));
}
@@ -67,7 +68,8 @@
{
// FIXME: program_solver must warn and/or break when exp is zero
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Div(*src1, Register(Register::general, Cpu::at)));
program_->text_section ().add_inst(new Mflo(*dest));
@@ -84,7 +86,8 @@
{
// FIXME: program_solver must warn and/or break when exp is zero
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Divu(*src1, Register(Register::general, Cpu::at)));
program_->text_section ().add_inst(new Mflo(*dest));
@@ -234,7 +237,8 @@
ProgramBuilder::add_sgt(Register *dest, Register *src1, Exp *src2)
{
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Slt(*dest, Register(Register::general, Cpu::at), *src1));
}
@@ -242,7 +246,8 @@
ProgramBuilder::add_sgtu(Register *dest, Register *src1, Exp *src2)
{
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Sltu(*dest, Register(Register::general, Cpu::at), *src1));
}
@@ -258,7 +263,8 @@
ProgramBuilder::add_sle(Register *dest, Register *src1, Exp *src2)
{
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Slt(*dest, Register(Register::general, Cpu::at), *src1));
program_->text_section ().add_inst(new Xori(*dest, *dest, new IntExp(1)));
@@ -273,7 +279,8 @@
ProgramBuilder::add_sleu(Register *dest, Register *src1, Exp *src2)
{
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Sltu(*dest, Register(Register::general, Cpu::at), *src1));
program_->text_section ().
@@ -288,7 +295,8 @@
ProgramBuilder::add_bne(Register *src1, Exp *src2, Exp *dest)
{
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Bne(*src1, Register(Register::general, Cpu::at), dest));
// This nop is in the delay slot
@@ -301,7 +309,8 @@
ProgramBuilder::add_beq(Register *src1, Exp *src2, Exp *dest)
{
program_->text_section ().
- add_inst(new Li(Register(Register::general, Cpu::at), src2));
+ add_inst(new Addiu(Register(Register::general, Cpu::at),
+ Register(Register::general, Cpu::zero), src2));
program_->text_section ().
add_inst(new Beq(*src1, Register(Register::general, Cpu::at), dest));
// This nop is in the delay slot
@@ -545,7 +554,10 @@
new IntExp(0)));
}
- // Load address ------------------------------------------
+ // Load --------------------------------------------------
+
+ // Load address
+ // FIXME: alias?
void
ProgramBuilder::add_la (Register *dest, Exp *exp, Register *base)
{
@@ -554,8 +566,8 @@
void
ProgramBuilder::add_la (Register *reg, Exp *exp)
{
- // FIXME: alias
- program_->text_section ().add_inst(new Li(*reg, exp));
+ program_->text_section ().
+ add_inst(new Addiu(*reg, Register(Register::general, Cpu::zero), exp));
}
} // namespace inst
Index: dev/nolimips.xml
--- dev/nolimips.xml (revision 124)
+++ dev/nolimips.xml (revision 125)
@@ -1026,15 +1026,11 @@
</syntax>
</instruction>
- <!-- FIXME, should be a complex form -->
- <instruction opcode="li" level="native"
kind="load">
+ <instruction opcode="li" level="pseudo"
kind="load">
<description>Move the constant imm into dest.</description>
- <format>
- <attribute type="Register" name="dest"/>
- <attribute type="Exp" name="imm"/>
- </format>
- <syntax>
+ <syntax alias="ori">
<token kind="register" />
+ <token kind="hidden" value="new Register(Register::general,
Cpu::zero)"/>
<token kind="immediate" />
</syntax>
</instruction>
20 Sep
20 Sep
8:37 p.m.
Do not forget to launch `bootstrap', since an instruction was removed
from nolimips.xml
--
Noe
21 Sep
21 Sep
9:02 a.m.
>> "Benoît" == Benoît Perrot
<benoit(a)lrde.epita.fr> writes:
Do not forget to launch `bootstrap', since an
instruction was removed
from nolimips.xml
That's not good. The Makefiles should handle this. You should fix
them rather than using bootstrap all the time. Have a look at
src/ast/Makefile.am to see how tc handles this.
8:46 p.m.
Akim Demaille <akim(a)epita.fr> writes:
No, it is not :(
Do not forget
to launch `bootstrap', since an instruction was removed
from nolimips.xml
That's not good. The Makefiles should handle this. You should fix them
rather than
using bootstrap all the time. Have a look at src/ast/Makefile.am to
see how tc handles this.
From src/ast/Makefile.am:
include $(srcdir)/ast-nodes.mk
[...]
$(srcdir)/ast-nodes.mk: $(gen_dir)/ast-nodes-mk-gen $(ast_gen_deps)
$(gen_dir)/ast-nodes-mk-gen < $(srcdir)/ast.xml >$@.tmp
mv -f $@.tmp $@
##
## I did not know that the generated Makefiles were so smart :P
## Nice!
$(srcdir)/ast-fwd-gen.stamp: $(gen_dir)/ast-fwd-gen $(ast_gen_deps)
@rm -rf $@.tmp
@touch $@.tmp
$(gen_dir)/ast-fwd-gen $(srcdir) < $(srcdir)/ast.xml
@mv -f $@.tmp $@
fwd.hh: ast-fwd-gen.stamp
##
## Why use such a mechanism to update stamp?
--
Noe
22 Sep
22 Sep
10:11 a.m.
>> "Benoît" == Benoît Perrot
<benoit(a)lrde.epita.fr> writes:
Akim Demaille <akim(a)epita.fr> writes:
No, it is not :(
Do not
forget to launch `bootstrap', since an instruction was removed
from nolimips.xml
That's not good. > The Makefiles should handle this. You should fix
them rather than
> using bootstrap all the time. Have a look at src/ast/Makefile.am to
> see how tc handles this.
From src/ast/Makefile.am:
include $(srcdir)/ast-nodes.mk
[...]
$(srcdir)/ast-nodes.mk: $(gen_dir)/ast-nodes-mk-gen
$(ast_gen_deps)
$(gen_dir)/ast-nodes-mk-gen < $(srcdir)/ast.xml >$@.tmp
mv -f $@.tmp $@
##
## I did not know that the generated Makefiles were so smart :P
## Nice!
$(srcdir)/ast-fwd-gen.stamp: $(gen_dir)/ast-fwd-gen
$(ast_gen_deps)
@rm -rf $@.tmp
@touch $@.tmp
$(gen_dir)/ast-fwd-gen $(srcdir) < $(srcdir)/ast.xml
@mv -f $@.tmp $@
fwd.hh: ast-fwd-gen.stamp
##
## Why use such a mechanism to update stamp?
Read Automake.texi.
----------------------------------------------------------------------
26.6 Handling Tools that Produce Many Outputs
=============================================
This section describes a `make' idiom that can be used when a tool
produces multiple output files. It is not specific to Automake and can
be used in ordinary `Makefile's.
Suppose we have a program called `foo' that will read one file
called `data.foo' and produce two files named `data.c' and `data.h'.
We want to write a `Makefile' rule that captures this one-to-two
dependency.
The naive rule is incorrect:
# This is incorrect.
data.c data.h: data.foo
foo data.foo
What the above rule really says is that `data.c' and `data.h' each
depend on `data.foo', and can each be built by running `foo data.foo'.
In other words it is equivalent to:
# We do not want this.
data.c: data.foo
foo data.foo
data.h: data.foo
foo data.foo
which means that `foo' can be run twice. Usually it will not be run
twice, because `make' implementations are smart enough to check for the
existence of the second file after the first one has been built; they
will therefore detect that it already exists. However there are a few
situations where it can run twice anyway:
* The most worrying case is when running a parallel `make'. If
`data.c' and `data.h' are built in parallel, two `foo data.foo'
commands will run concurrently. This is harmful.
* Another case is when the dependency (here `data.foo') is (or
depends upon) a phony target.
A solution that works with parallel `make' but not with phony
dependencies is the following:
data.c data.h: data.foo
foo data.foo
data.h: data.c
The above rules are equivalent to
data.c: data.foo
foo data.foo
data.h: data.foo data.c
foo data.foo
therefore a parallel `make' will have to serialize the builds of
`data.c' and `data.h', and will detect that the second is no longer
needed once the first is over.
Using this pattern is probably enough for most cases. However it
does not scale easily to more output files (in this scheme all output
files must be totally ordered by the dependency relation), so we will
explore a more complicated solution.
Another idea is to write the following:
# There is still a problem with this one.
data.c: data.foo
foo data.foo
data.h: data.c
The idea is that `foo data.foo' is run only when `data.c' needs to be
updated, but we further state that `data.h' depends upon `data.c'.
That way, if `data.h' is required and `data.foo' is out of date, the
dependency on `data.c' will trigger the build.
This is almost perfect, but suppose we have built `data.h' and
`data.c', and then we erase `data.h'. Then, running `make data.h' will
not rebuild `data.h'. The above rules just state that `data.c' must be
up-to-date with respect to `data.foo', and this is already the case.
What we need is a rule that forces a rebuild when `data.h' is
missing. Here it is:
data.c: data.foo
foo data.foo
data.h: data.c
@if test -f $@; then :; else \
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
The above scales easily to more outputs and more inputs. One of the
output is picked up to serve as a witness of the run of the command, it
depends upon all inputs, and all other outputs depend upon it. For
instance if `foo' should additionally read `data.bar' and also produce
`data.w' and `data.x', we would write:
data.c: data.foo data.bar
foo data.foo data.bar
data.h data.w data.x: data.c
@if test -f $@; then :; else \
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
There is still a minor problem with this setup. `foo' outputs four
files, but we do not know in which order these files are created.
Suppose that `data.h' is created before `data.c'. Then we have a weird
situation. The next time `make' is run, `data.h' will appear older
than `data.c', the second rule will be triggered, a shell will be
started to execute the `if...fi' command, but actually it will just
execute the `then' branch, that is: nothing. In other words, because
the witness we selected is not the first file created by `foo', `make'
will start a shell to do nothing each time it is run.
A simple riposte is to fix the timestamps when this happens.
data.c: data.foo data.bar
foo data.foo data.bar
data.h data.w data.x: data.c
@if test -f $@; then \
touch $@; \
else \
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
Another solution, not incompatible with the previous one, is to use a
different and dedicated file as witness, rather than using any of
`foo''s outputs.
data.stamp: data.foo data.bar
@rm -f data.tmp
@touch data.tmp
foo data.foo data.bar
@mv -f data.tmp $@
data.c data.h data.w data.x: data.stamp
@if test -f $@; then \
touch $@; \
else \
rm -f data.stamp; \
$(MAKE) $(AM_MAKEFLAGS) data.stamp; \
fi
`data.tmp' is created before `foo' is run, so it has a timestamp
older than output files output by `foo'. It is then renamed to
`data.stamp' after `foo' has run, because we do not want to update
`data.stamp' if `foo' fails.
Using a dedicated witness like this is very handy when the list of
output files is not known beforehand. As an illustration, consider the
following rules to compile many `*.el' files into `*.elc' files in a
single command. It does not matter how `ELFILES' is defined (as long
as it is not empty: empty targets are not accepted by POSIX).
ELFILES = one.el two.el three.el ...
ELCFILES = $(ELFILES:=c)
elc-stamp: $(ELFILES)
@rm -f elc-temp
@touch elc-temp
$(elisp_comp) $(ELFILES)
@mv -f elc-temp $@
$(ELCFILES): elc-stamp
@if test -f $@; then \
touch $@; \
else \
rm -f elc-stamp; \
$(MAKE) $(AM_MAKEFLAGS) elc-stamp; \
fi
For completeness it should be noted that GNU `make' is able to
express rules with multiple output files using pattern rules (*note
Pattern Rule Examples: (make)Pattern Examples.). We do not discuss
pattern rules here because they are not portable, but they can be
convenient in packages that assume GNU `make'.
11:43 p.m.
Akim Demaille <akim(a)epita.fr> writes:
[...]
Oh la :)
You explained me,
Then I used,
The stamp trick
When I was
Working on TC's AST generation
I meant: "why touch $@ is not enough?"
Because:
`data.tmp' is created before `foo' is run, so it has a timestamp
older than output files output by `foo'. It is then renamed to
`data.stamp' after `foo' has run, because we do not want to update
`data.stamp' if `foo' fails.
Thanks!
--
Noe
$(srcdir)/ast-fwd-gen.stamp: $(gen_dir)/ast-fwd-gen $(ast_gen_deps)
@rm -rf $@.tmp
@touch $@.tmp
$(gen_dir)/ast-fwd-gen $(srcdir) < $(srcdir)/ast.xml
@mv -f $@.tmp $@
fwd.hh: ast-fwd-gen.stamp
##
## Why use such a mechanism to update stamp?
Read Automake.texi.
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2 participants
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Noe