[libc-commits] [libc] 137740e - [libc] Exclude few unused bits from x86 state for Windows

[Hedin García via libc-commits]

Author: Hedin Garca
Date: 2021-07-21T13:11:10Z
New Revision: 137740ecedf1ac61ad29e16badf1519d7c211c42

URL: https://github.com/llvm/llvm-project/commit/137740ecedf1ac61ad29e16badf1519d7c211c42
DIFF: https://github.com/llvm/llvm-project/commit/137740ecedf1ac61ad29e16badf1519d7c211c42.diff

LOG: [libc] Exclude few unused bits from x86 state for Windows

Windows fenv_t does not include the MXCSR register and
the unused bits at the end of the x87 status. So we
exclude them in our struct definitions to make it
easy to read/write the state. getEnv and setEnv
were also excluded to avoid using MXCSR, but a
forthcoming patch will handle these functions.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D106386

Added: 
    

Modified: 
    libc/utils/FPUtil/x86_64/FEnv.h

Removed: 
    


################################################################################
diff  --git a/libc/utils/FPUtil/x86_64/FEnv.h b/libc/utils/FPUtil/x86_64/FEnv.h
index 6718ef5f03a1a..8ae10afde084f 100644
--- a/libc/utils/FPUtil/x86_64/FEnv.h
+++ b/libc/utils/FPUtil/x86_64/FEnv.h
@@ -91,12 +91,16 @@ struct X87StateDescriptor {
   uint16_t StatusWord;
   uint16_t Unused2;
   // TODO: Elaborate the remaining 20 bytes as required.
+#if !(defined(_WIN32))
   uint32_t _[5];
+#endif
 };
 
 struct FPState {
   X87StateDescriptor X87Status;
+#if !(defined(_WIN32))
   uint32_t MXCSR;
+#endif
 };
 
 static_assert(
@@ -346,6 +350,7 @@ static inline int setRound(int mode) {
   return 0;
 }
 
+#if !(defined(_WIN32))
 static inline int getEnv(fenv_t *envp) {
   internal::FPState *state = reinterpret_cast<internal::FPState *>(envp);
   internal::getX87StateDescriptor(state->X87Status);
@@ -360,6 +365,7 @@ static inline int setEnv(const fenv_t *envp) {
   internal::writeMXCSR(state->MXCSR);
   return 0;
 }
+#endif
 
 } // namespace fputil
 } // namespace __llvm_libc