There are many tests that specify a target triple/CPU flags but no
DataLayout which can lead to IR being generated that has unusual
behaviour. This commit attempts to use the default DataLayout based
on the relevant flags if there is no explicit override on the command
line or in the IR file.
One thing that is not currently possible to differentiate from a missing
datalayout `target datalayout = ""` in the IR file since the current
APIs don't allow detecting this case. If it is considered useful to
support this case (instead of passing "-data-layout=" on the command
line), I can change IR parsers to track whether they have seen such a
directive and change the callback type.
Differential Revision: https://reviews.llvm.org/D141060
Do the LDS frame calculation once, in the IR pass, instead of repeating the work in the backend.
Prior to this patch:
The IR lowering pass sets up a per-kernel LDS frame and annotates the variables with absolute_symbol
metadata so that the assembler can build lookup tables out of it. There is a fragile association between
kernel functions and named structs which is used to recompute the frame layout in the backend, with
fatal_errors catching inconsistencies in the second calculation.
After this patch:
The IR lowering pass additionally sets a frame size attribute on kernels. The backend uses the same
absolute_symbol metadata that the assembler uses to place objects within that frame size.
Deleted the now dead allocation code from the backend. Left for a later cleanup:
- enabling lowering for anonymous functions
- removing the elide-module-lds attribute (test churn, it's not used by llc any more)
- adjusting the dynamic alignment check to not use symbol names
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D155190
Post ISel, LDS variables are absolute values. Representing them as
such is simpler than the frame recalculation currently used to build assembler
tables from their addresses.
This is a precursor to lowering dynamic/external LDS accesses from non-kernel
functions.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D144221
IR is now always parsed in opaque pointer mode, unless
-opaque-pointers=0 is explicitly given. There is no automatic
detection of typed pointers anymore.
The -opaque-pointers=0 option is added to any remaining IR tests
that haven't been migrated yet.
Differential Revision: https://reviews.llvm.org/D141912
Renames the current lowering scheme to "module" and introduces two new
ones, "kernel" and "table", plus a "hybrid" that chooses between those three
on a per-variable basis.
Unit tests are set up to pass with the default lowering of "module" or "hybrid"
with this patch defaulting to "module", which will be a less dramatic codegen
change relative to the current. This reflects the sparsity of test coverage for
the table lowering method. Hybrid is better than module in every respect and
will be default in a subsequent patch.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D139433
Renames the current lowering scheme to "module" and introduces two new
ones, "kernel" and "table", plus a "hybrid" that chooses between those three
on a per-variable basis.
Unit tests are set up to pass with the default lowering of "module" or "hybrid"
with this patch defaulting to "module", which will be a less dramatic codegen
change relative to the current. This reflects the sparsity of test coverage for
the table lowering method. Hybrid is better than module in every respect and
will be default in a subsequent patch.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D139433
The association between kernel and struct is done by symbol name.
This doesn't work robustly for anonymous kernels as shown by the modified
test case.
An alternative association between function and struct can be constructed
if necessary, probably though metadata, but on the basis that we currently
miscompile anonymous kernels and that they are difficult to construct from
application code and difficult to call from the runtime, this patch makes
it a fatal error for now.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D134741
Introduces a string attribute, amdgpu-requires-module-lds, to allow
eliding the module.lds block from kernels. Will allocate the block as before
if the attribute is missing or has its default value of true.
Patch uses the new attribute to detect the simplest possible instance of this,
where a kernel makes no calls and thus cannot call any functions that use LDS.
Tests updated to match, coverage was already good. Interesting cases is in
lower-module-lds-offsets where annotating the kernel allows the backend to pick
a different (in this case better) variable ordering than previously. A later
patch will avoid moving kernel variables into module.lds when the kernel can
have this attribute, allowing optimal ordering and locally unused variable
elimination.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D122091
