__builtin_cpu_supports and __builtin_cpu_is use information in __cpu_model to decide cpu features. Before this change, __cpu_model was not declared as dso local. The generated code looks up the address in GOT when reading __cpu_model. This makes it impossible to use these functions in ifunc, because at that time GOT entries have not been relocated. This change makes it dso local.
Differential Revision: https://reviews.llvm.org/D53850
llvm-svn: 349825
__builtin_cpu_supports and __builtin_cpu_is use information in __cpu_model to decide cpu features. Before this change, __cpu_model was not declared as dso local. The generated code looks up the address in GOT when reading __cpu_model. This makes it impossible to use these functions in ifunc, because at that time GOT entries have not been relocated. This change makes it dso local.
Differential Revision: https://reviews.llvm.org/D53850
llvm-svn: 348978
libgcc supports more than 32 features by adding a new 32-bit variable __cpu_features2.
This adds the clang support for checking these feature bits.
Patches for compiler-rt and llvm to support this are coming as well.
Probably still need an additional patch for target multiversioning in clang.
Differential Revision: https://reviews.llvm.org/D53458
llvm-svn: 344832
Summary:
The multiversioning code repurposed the code from __builtin_cpu_supports for checking if a single feature is enabled. That code essentially performed (_cpu_features & (1 << C)) != 0. But with the multiversioning path, the mask is no longer guaranteed to be a power of 2. So we return true anytime any one of the bits in the mask is set not just all of the bits.
The correct check is (_cpu_features & mask) == mask
Reviewers: erichkeane, echristo
Reviewed By: echristo
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D53460
llvm-svn: 344824
This adds builtin_cpu_init which will emit a call to cpu_indicator_init in libgcc or compiler-rt.
This is needed to support builtin_cpu_supports/builtin_cpu_is in an ifunc resolver.
Differential Revision: https://reviews.llvm.org/D36336
llvm-svn: 311874
This matches the implementation of the gcc support for the same
feature, including checking the values set up by libgcc at runtime.
The structure looks like this:
unsigned int __cpu_vendor;
unsigned int __cpu_type;
unsigned int __cpu_subtype;
unsigned int __cpu_features[1];
with a set of enums to match various fields that are field out after
parsing the output of the cpuid instruction.
This also adds a set of errors checking for valid input (and cpu).
compiler-rt support for this and the other builtins in this family
(__builtin_cpu_init and __builtin_cpu_is) are forthcoming.
llvm-svn: 240994
Haibo Huang