Revision: 9087
Author: [email protected]
Date: Wed Aug 31 08:34:33 2011
Log: MIPS: port ARM: Changed the handling of compiletime CPU feature
detection
Another port of an older arm commit, which was not upstreamed at the time.
Ported r7754 (ef678641)
BUG=
TEST=
Review URL: http://codereview.chromium.org/7809016
http://code.google.com/p/v8/source/detail?r=9087
Modified:
/branches/bleeding_edge/src/mips/assembler-mips.cc
/branches/bleeding_edge/src/platform-linux.cc
=======================================
--- /branches/bleeding_edge/src/mips/assembler-mips.cc Tue Aug 30 00:36:31
2011
+++ /branches/bleeding_edge/src/mips/assembler-mips.cc Wed Aug 31 08:34:33
2011
@@ -49,11 +49,47 @@
unsigned CpuFeatures::supported_ = 0;
unsigned CpuFeatures::found_by_runtime_probing_ = 0;
+
+// Get the CPU features enabled by the build. For cross compilation the
+// preprocessor symbols CAN_USE_FPU_INSTRUCTIONS
+// can be defined to enable FPU instructions when building the
+// snapshot.
+static uint64_t CpuFeaturesImpliedByCompiler() {
+ uint64_t answer = 0;
+#ifdef CAN_USE_FPU_INSTRUCTIONS
+ answer |= 1u << FPU;
+#endif // def CAN_USE_FPU_INSTRUCTIONS
+
+#ifdef __mips__
+ // If the compiler is allowed to use FPU then we can use FPU too in our
code
+ // generation even when generating snapshots. This won't work for cross
+ // compilation.
+#if(defined(__mips_hard_float) && __mips_hard_float != 0)
+ answer |= 1u << FPU;
+#endif // defined(__mips_hard_float) && __mips_hard_float != 0
+#endif // def __mips__
+
+ return answer;
+}
+
+
void CpuFeatures::Probe() {
ASSERT(!initialized_);
#ifdef DEBUG
initialized_ = true;
#endif
+
+ // Get the features implied by the OS and the compiler settings. This is
the
+ // minimal set of features which is also allowed for generated code in
the
+ // snapshot.
+ supported_ |= OS::CpuFeaturesImpliedByPlatform();
+ supported_ |= CpuFeaturesImpliedByCompiler();
+
+ if (Serializer::enabled()) {
+ // No probing for features if we might serialize (generate snapshot).
+ return;
+ }
+
// If the compiler is allowed to use fpu then we can use fpu too in our
// code generation.
#if !defined(__mips__)
@@ -62,11 +98,7 @@
supported_ |= 1u << FPU;
}
#else
- if (Serializer::enabled()) {
- supported_ |= OS::CpuFeaturesImpliedByPlatform();
- return; // No features if we might serialize.
- }
-
+ // Probe for additional features not already known to be available.
if (OS::MipsCpuHasFeature(FPU)) {
// This implementation also sets the FPU flags if
// runtime detection of FPU returns true.
=======================================
--- /branches/bleeding_edge/src/platform-linux.cc Wed Aug 17 01:24:36 2011
+++ /branches/bleeding_edge/src/platform-linux.cc Wed Aug 31 08:34:33 2011
@@ -130,13 +130,7 @@
uint64_t OS::CpuFeaturesImpliedByPlatform() {
-#if(defined(__mips_hard_float) && __mips_hard_float != 0)
- // Here gcc is telling us that we are on an MIPS and gcc is assuming
that we
- // have FPU instructions. If gcc can assume it then so can we.
- return 1u << FPU;
-#else
return 0; // Linux runs on anything.
-#endif
}
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