runtime: remove duplicate cpu feature detection on x86

This also allows the GODEBUGCPU options to change the
support_* runtime cpu feature variable values.

Change-Id: I884c5f03993afc7e3344ff2fd471a2c6cfde43d4
Reviewed-on: https://go-review.googlesource.com/114615
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/runtime/asm_386.s

@@ -164,42 +164,6 @@ notintel:
 	TESTL	$(1<<23), DX // MMX
 	JZ	bad_proc
 
-	TESTL	$(1<<26), DX // SSE2
-	SETNE	runtime·support_sse2(SB)
-
-	TESTL	$(1<<19), DI // SSE4.1
-	SETNE	runtime·support_sse41(SB)
-
-	TESTL	$(1<<23), DI // POPCNT
-	SETNE	runtime·support_popcnt(SB)
-
-	TESTL	$(1<<27), DI // OSXSAVE
-	SETNE	runtime·support_osxsave(SB)
-
-eax7:
-	// Load EAX=7/ECX=0 cpuid flags
-	CMPL	SI, $7
-	JLT	osavx
-	MOVL	$7, AX
-	MOVL	$0, CX
-	CPUID
-
-	TESTL	$(1<<9), BX // ERMS
-	SETNE	runtime·support_erms(SB)
-
-osavx:
-	// nacl does not support XGETBV to test
-	// for XMM and YMM OS support.
-#ifndef GOOS_nacl
-	CMPB	runtime·support_osxsave(SB), $1
-	JNE	nocpuinfo
-	MOVL	$0, CX
-	// For XGETBV, OSXSAVE bit is required and sufficient
-	XGETBV
-	ANDL	$6, AX
-	CMPL	AX, $6 // Check for OS support of XMM and YMM registers.
-#endif
-
 nocpuinfo:
 	// if there is an _cgo_init, call it to let it
 	// initialize and to set up GS.  if not,

src/runtime/asm_amd64.s

@@ -127,38 +127,6 @@ notintel:
 	CPUID
 	MOVL	AX, runtime·processorVersionInfo(SB)
 
-	TESTL	$(1<<26), DX // SSE2
-	SETNE	runtime·support_sse2(SB)
-
-	TESTL	$(1<<19), CX // SSE4.1
-	SETNE	runtime·support_sse41(SB)
-
-	TESTL	$(1<<23), CX // POPCNT
-	SETNE	runtime·support_popcnt(SB)
-
-	TESTL	$(1<<27), CX // OSXSAVE
-	SETNE	runtime·support_osxsave(SB)
-
-eax7:
-	// Load EAX=7/ECX=0 cpuid flags
-	CMPL	SI, $7
-	JLT	osavx
-	MOVL	$7, AX
-	MOVL	$0, CX
-	CPUID
-
-	TESTL	$(1<<9), BX // ERMS
-	SETNE	runtime·support_erms(SB)
-
-osavx:
-	CMPB	runtime·support_osxsave(SB), $1
-	JNE	nocpuinfo
-	MOVL	$0, CX
-	// For XGETBV, OSXSAVE bit is required and sufficient
-	XGETBV
-	ANDL	$6, AX
-	CMPL	AX, $6 // Check for OS support of XMM and YMM registers.
-
 nocpuinfo:
 	// if there is an _cgo_init, call it.
 	MOVQ	_cgo_init(SB), AX

src/runtime/asm_amd64p32.s

@@ -47,45 +47,7 @@ notintel:
 	CPUID
 	MOVL	AX, runtime·processorVersionInfo(SB)
 
-	TESTL	$(1<<26), DX // SSE2
-	SETNE	runtime·support_sse2(SB)
-
-	TESTL	$(1<<19), CX // SSE4.1
-	SETNE	runtime·support_sse41(SB)
-
-	TESTL	$(1<<23), CX // POPCNT
-	SETNE	runtime·support_popcnt(SB)
-
-	TESTL	$(1<<27), CX // OSXSAVE
-	SETNE	runtime·support_osxsave(SB)
-
-eax7:
-	// Load EAX=7/ECX=0 cpuid flags
-	CMPL	SI, $7
-	JLT	osavx
-	MOVL	$7, AX
-	MOVL	$0, CX
-	CPUID
-
-	TESTL	$(1<<9), BX // ERMS
-	SETNE	runtime·support_erms(SB)
-
-osavx:
-	// nacl does not support XGETBV to test
-	// for XMM and YMM OS support.
-#ifndef GOOS_nacl
-	CMPB	runtime·support_osxsave(SB), $1
-	JNE	nocpuinfo
-	MOVL	$0, CX
-	// For XGETBV, OSXSAVE bit is required and sufficient
-	XGETBV
-	ANDL	$6, AX
-	CMPL	AX, $6 // Check for OS support of XMM and YMM registers.
-#endif
-
 nocpuinfo:
-
-needtls:
 	LEAL	runtime·m0+m_tls(SB), DI
 	CALL	runtime·settls(SB)
 

src/runtime/proc.go

@@ -5,6 +5,7 @@
 package runtime
 
 import (
+	"internal/cpu"
 	"runtime/internal/atomic"
 	"runtime/internal/sys"
 	"unsafe"
@@ -507,6 +508,11 @@ func cpuinit() {
 	}
 
 	internal_cpu_initialize(env)
+
+	support_erms = cpu.X86.HasERMS
+	support_popcnt = cpu.X86.HasPOPCNT
+	support_sse2 = cpu.X86.HasSSE2
+	support_sse41 = cpu.X86.HasSSE41
 }
 
 // The bootstrap sequence is:

src/runtime/runtime2.go

@@ -833,7 +833,7 @@ var (
 	newprocs   int32
 
 	// Information about what cpu features are available.
-	// Set on startup in asm_{386,amd64,amd64p32}.s.
+	// Set on startup in runtime.cpuinit.
 	// Packages outside the runtime should not use these
 	// as they are not an external api.
 	// TODO: deprecate these; use internal/cpu directly.
@@ -841,7 +841,6 @@ var (
 	isIntel              bool
 	lfenceBeforeRdtsc    bool
 	support_erms         bool
-	support_osxsave      bool
 	support_popcnt       bool
 	support_sse2         bool
 	support_sse41        bool