[Qemu-devel] [PATCH] tcg/i386: Fix build for systems without working cpuid.h (MacOSX, Win32)

[Peter Maydell <peter.maydell@linaro.org>]

Win32 doesn't have a cpuid.h, and MacOSX may have one but without
the __cpuid() function we use, which means that commit 9d2eec20
broke the build for those platforms. Fix this by tightening up
our configure cpuid.h check to test that the functions we need
are present, and adding some missing #ifdef guerds in
tcg/i386/tcg-target.c.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Tested with Linux x86/64 gcc build, Linux x86/64 clang build,
W32 cross-build and MacOSX 10.8 build. If somebody would like to
review this I'll apply it directly to unbreak things.
Apologies for not catching it before I pushed the tcg pullreq;
I had forgotten to add the 'build on w32' command to my script.

 configure             | 8 +++++++-
 tcg/i386/tcg-target.c | 4 +++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index 4648117..a2af9db 100755
--- a/configure
+++ b/configure
@@ -3564,7 +3564,13 @@ cpuid_h=no
 cat > $TMPC << EOF
 #include <cpuid.h>
 int main(void) {
-  return 0;
+    unsigned a, b, c, d;
+    int max = __get_cpuid_max(0, 0);
+
+    if (max >= 1) {
+        __cpuid(1, a, b, c, d);
+    }
+    return 0;
 }
 EOF
 if compile_prog "" "" ; then
diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
index fef1717..f832282 100644
--- a/tcg/i386/tcg-target.c
+++ b/tcg/i386/tcg-target.c
@@ -115,7 +115,7 @@ static const int tcg_target_call_oarg_regs[] = {
    is available.  */
 #if TCG_TARGET_REG_BITS == 64
 # define have_cmov 1
-#elif defined(CONFIG_CPUID_H)
+#elif defined(CONFIG_CPUID_H) && defined(bit_CMOV)
 static bool have_cmov;
 #else
 # define have_cmov 0
@@ -2295,6 +2295,7 @@ static void tcg_target_qemu_prologue(TCGContext *s)
 
 static void tcg_target_init(TCGContext *s)
 {
+#ifdef CONFIG_CPUID_H
     unsigned a, b, c, d;
     int max = __get_cpuid_max(0, 0);
 
@@ -2323,6 +2324,7 @@ static void tcg_target_init(TCGContext *s)
         have_bmi2 = (b & bit_BMI2) != 0;
 #endif
     }
+#endif
 
     if (TCG_TARGET_REG_BITS == 64) {
         tcg_regset_set32(tcg_target_available_regs[TCG_TYPE_I32], 0, 0xffff);
-- 
1.8.5