Commit Graph

7 Commits

Author SHA1 Message Date
Jonas Hahnfeld ea08c4cd1c [CUDA] Fix static device variables with -fgpu-rdc
NVPTX does not allow dots in the identifier, so ptxas errors out with
   fatal   : Parsing error near '.static': syntax error
because it parses .static as a directive. Avoid this problem by using
two underscores, similar to what OpenMP does for outlined functions.

Differential Revision: https://reviews.llvm.org/D108456
2021-08-25 09:31:22 +02:00
Jay Foad 157473a58f [IR] Simplify createReplacementInstr
NFCI, although the test change shows that ConstantExpr::getAsInstruction
is better than the old implementation of createReplacementInstr because
it propagates things like the sdiv "exact" flag.

Differential Revision: https://reviews.llvm.org/D104124
2021-06-23 10:47:43 +01:00
Fangrui Song 37561ba89b -fno-semantic-interposition: Don't set dso_local on GlobalVariable
`clang -fpic -fno-semantic-interposition` may set dso_local on variables for -fpic.

GCC folks consider there are 'address interposition' and 'semantic interposition',
and 'disabling semantic interposition' can optimize function calls but
cannot change variable references to use local aliases
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100483).

This patch removes dso_local for variables in
`clang -fpic -fno-semantic-interposition` mode so that the built shared objects can
work with copy relocations. Building llvm-project tiself with
-fno-semantic-interposition (D102453) should now be safe with trunk Clang.

Example:
```
// a.c
int var;
int *addr() { return var; }

// old: cannot be interposed
movslq  .Lvar$local(%rip), %rax
// new: can be interposed
movq    var@GOTPCREL(%rip), %rax
movslq  (%rax), %rax
```

The local alias lowering for `GlobalVariable`s is kept in case there is a
future option allowing local aliases.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D102583
2021-05-19 16:08:28 -07:00
Yaxun (Sam) Liu 47acdec1dd [CUDA][HIP] Support accessing static device variable in host code for -fgpu-rdc
For -fgpu-rdc mode, static device vars in different TU's may have the same name.
To support accessing file-scope static device variables in host code, we need to give them
a distinct name and external linkage. This can be done by postfixing each static device variable with
a distinct CUID (Compilation Unit ID) hash.

Since the static device variables have different name across compilation units, now we let
them have external linkage so that they can be looked up by the runtime.

Reviewed by: Artem Belevich, and Jon Chesterfield

Differential Revision: https://reviews.llvm.org/D85223
2021-02-24 18:23:45 -05:00
Yaxun (Sam) Liu a3ce7f5cd2 [HIP] Fix managed variable linkage
Currently managed variables are emitted as undefined symbols, which
causes difficulty for diagnosing undefined symbols for non-managed
variables.

This patch transforms managed variables in device compilation so that
they can be emitted as normal variables.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D96195
2021-02-23 22:34:45 -05:00
Yaxun (Sam) Liu b008ea304d [CUDA][HIP] Fix device variable linkage
For -fgpu-rdc, shadow variables should not be internalized, otherwise
they cannot be accessed by other TUs. This is necessary because
the shadow variable of external device variables are always
emitted as undefined symbols, which need to resolve to a global
symbols.

Managed variables need to be emitted as undefined symbols
in device compilations.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D95901
2021-02-05 15:11:12 -05:00
Yaxun (Sam) Liu 622eaa4a4c [HIP] Support __managed__ attribute
This patch implements codegen for __managed__ variable attribute for HIP.

Diagnostics will be added later.

Differential Revision: https://reviews.llvm.org/D94814
2021-01-22 11:43:58 -05:00