| Age | Commit message (Collapse) | Author |
|---|
|
|
|
This makes it easier to determine which flag to pass to show the
desired debug info.
|
|
SCCP is currently the one and only
pass which seriously affects control
flow; so we must compute loop costs
afterwards.
|
|
Previously, we would skip ssa construction when
a temporary has a single definition. This is
only part of the ssa invariant: we must also
check that all uses are dominated by the single
definition. The new code does this.
In fact, qbe does not store all the dominators
for a block, so instead of walking the idom
linked list we use a rough heuristic and declare
conservatively that B0 dominates B1 when one of
the two conditions is true:
a. B0 is the start block
b. B0 is B1
Some measurements on a big file from Michael
Forney show that the code is still as fast as
before this patch.
|
|
|
|
This big diff does multiple changes to allow
the addition of new targets to qbe. The
changes are listed below in decreasing order
of impact.
1. Add a new Target structure.
To add support for a given target, one has to
implement all the members of the Target
structure. All the source files where changed
to use this interface where needed.
2. Single out amd64-specific code.
In this commit, the amd64 target T_amd64_sysv
is the only target available, it is implemented
in the amd64/ directory. All the non-static
items in this directory are prefixed with either
amd64_ or amd64_sysv (for items that are
specific to the System V ABI).
3. Centralize Ops information.
There is now a file 'ops.h' that must be used to
store all the available operations together with
their metadata. The various targets will only
select what they need; but it is beneficial that
there is only *one* place to change to add a new
instruction.
One good side effect of this change is that any
operation 'xyz' in the IL now as a corresponding
'Oxyz' in the code.
4. Misc fixes.
One notable change is that instruction selection
now generates generic comparison operations and
the lowering to the target's comparisons is done
in the emitter.
GAS directives for data are the same for many
targets, so data emission was extracted in a
file 'gas.c'.
5. Modularize the Makefile.
The Makefile now has a list of C files that
are target-independent (SRC), and one list
of C files per target. Each target can also
use its own 'all.h' header (for example to
define registers).
|
|
Notably, this adds a new pass to get rid of
jumps on jumps.
|
|
|
|
|
|
While a minimal dead store elimination is not
implemented, the generated code looks quite a
bit better with them enabled. It also is quite
cheap.
|
|
This change is backward compatible, calls to
"variadic" functions (like printf) must now be
annotated (with ...).
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Abi lowering does not need use counts, but
they are needed for instruction selection.
I changed main to call filluse() between
these two passes.
|
|
|
|
|
