update C comments

Author: picnixz

Include/internal/pycore_cpuinfo.h

@@ -29,7 +29,11 @@ extern "C" {
 
 typedef struct py_cpuid_features {
     uint32_t maxleaf;
-    /* Macro to declare a member flag of 'py_cpuid_features' as a uint8_t. */
+    /*
+     * Macro to declare a member flag of 'py_cpuid_features' as a uint8_t.
+     * Whenever this macro is used, do not forget to update the number of
+     * fields and the bitsize of the 'ready' member (see structure end).
+     */
 #define _Py_CPUID_DECL_FLAG(MEMBER_NAME)    uint8_t MEMBER_NAME:1
     // --- Streaming SIMD Extensions ------------------------------------------
     _Py_CPUID_DECL_FLAG(sse);
@@ -94,8 +98,8 @@ typedef struct py_cpuid_features {
     _Py_CPUID_DECL_FLAG(popcnt);
     _Py_CPUID_DECL_FLAG(pclmulqdq);
 
-    _Py_CPUID_DECL_FLAG(xsave);     // XSAVE/XRSTOR/XSETBV/XGETBV
-    _Py_CPUID_DECL_FLAG(osxsave);   // XSAVE is enabled by the OS
+    _Py_CPUID_DECL_FLAG(xsave);   // XSAVE/XRSTOR/XSETBV/XGETBV
+    _Py_CPUID_DECL_FLAG(osxsave); // XSAVE is enabled by the OS
 
     // --- XCR0 register bits -------------------------------------------------
     _Py_CPUID_DECL_FLAG(xcr0_sse);

Python/cpuinfo.c

@@ -162,6 +162,7 @@ detect_cpuid_maxleaf(void)
 static inline void
 detect_cpuid_features(py_cpuid_features *flags, CPUID_REG ecx, CPUID_REG edx)
 {
+    assert(flags->maxleaf >= 1);
     // Keep the ordering and newlines as they are declared in the structure.
 #ifdef SIMD_SSE_INSTRUCTIONS_DETECTION_GUARD
 #ifdef Py_CAN_COMPILE_SIMD_SSE_INSTRUCTIONS
@@ -206,6 +207,7 @@ static inline void
 detect_cpuid_extended_features_L7S0(py_cpuid_features *flags,
                                     CPUID_REG ebx, CPUID_REG ecx, CPUID_REG edx)
 {
+    assert(flags->maxleaf >= 7);
     (void)ebx, (void)ecx, (void)edx; // to suppress unused warnings
     // Keep the ordering and newlines as they are declared in the structure.
 #ifdef SIMD_AVX2_INSTRUCTIONS_DETECTION_GUARD
@@ -282,6 +284,7 @@ detect_cpuid_extended_features_L7S1(py_cpuid_features *flags,
                                     CPUID_REG ecx,
                                     CPUID_REG edx)
 {
+    assert(flags->maxleaf >= 7);
     (void)eax, (void)ebx, (void)ecx, (void)edx; // to suppress unused warnings
     // Keep the ordering and newlines as they are declared in the structure.
 #ifdef SIMD_AVX_INSTRUCTIONS_DETECTION_GUARD
@@ -309,6 +312,7 @@ static inline void
 detect_cpuid_xsave_state(py_cpuid_features *flags)
 {
     // Keep the ordering and newlines as they are declared in the structure.
+    assert(flags->maxleaf >= 1);
 #ifdef HAS_XGETBV_SUPPORT
     uint64_t xcr0 = flags->osxsave ? get_xgetbv(0) : 0;
     flags->xcr0_sse = XSAVE_CHECK_REG(xcr0, XCR0_SSE);
@@ -501,6 +505,7 @@ cpuid_detect_l1_features(py_cpuid_features *flags)
 static inline void
 cpuid_detect_l7s0_features(py_cpuid_features *flags)
 {
+    assert(flags->maxleaf >= 7);
     CPUID_REG eax = 0, ebx = 0, ecx = 0, edx = 0;
     get_cpuid_info(7, 0, &eax, &ebx, &ecx, &edx);
     detect_cpuid_extended_features_L7S0(flags, ebx, ecx, edx);
@@ -513,6 +518,7 @@ cpuid_detect_l7s0_features(py_cpuid_features *flags)
 static inline void
 cpuid_detect_l7s1_features(py_cpuid_features *flags)
 {
+    assert(flags->maxleaf >= 7);
     CPUID_REG eax = 0, ebx = 0, ecx = 0, edx = 0;
     get_cpuid_info(7, 1, &eax, &ebx, &ecx, &edx);
     detect_cpuid_extended_features_L7S1(flags, eax, ebx, ecx, edx);