Initial import

libc/dce.h

@@ -0,0 +1,123 @@
+#ifndef COSMOPOLITAN_LIBC_DCE_H_
+#define COSMOPOLITAN_LIBC_DCE_H_
+#include "libc/nexgen32e/kcpuids.h"
+/*─────────────────────────────────────────────────────────────────────────────╗
+│ cosmopolitan § autotune » dead code elimination                              │
+╚─────────────────────────────────────────────────────────────────────────────*/
+
+/**
+ * Supported Platforms Tuning Knob (Runtime & Compile-Time)
+ *
+ * Cosmopolitan's design allows us to support eight platforms. We enable
+ * them all by default, since we're able to do eight so efficiently. We
+ * can't do more, due to the way the 80x86 instruction set is encoded.
+ *
+ * The user may optionally tune this bitmask, which effectively asks the
+ * compiler to leave out system call polyfills for a platform, which may
+ * offer marginal improvements in terms of code size and performance, at
+ * the cost of portability.
+ */
+#ifndef SUPPORT_VECTOR
+#define SUPPORT_VECTOR 0b11111111
+#endif
+#define LINUX   1
+#define METAL   2
+#define WINDOWS 4
+#define XNU     8
+#define OPENBSD 16
+#define FREEBSD 32
+/* #define YOUR_CLOUD_PLATFORM_HERE 64  /\* jtunney@gmail.com *\/ */
+/* #define YOUR_CLOUD_PLATFORM_HERE 128 /\* jtunney@gmail.com *\/ */
+
+#ifdef NDEBUG
+#define NoDebug() 1
+#else
+#define NoDebug() 0
+#endif
+
+#ifdef MODE_DBG
+#define IsModeDbg() 1
+#else
+#define IsModeDbg() 0
+#endif
+
+#ifdef __MFENTRY__
+#define HaveFentry() 1
+#else
+#define HaveFentry() 0
+#endif
+
+#ifdef TRUSTWORTHY
+#define IsTrustworthy() 1
+#else
+#define IsTrustworthy() 0
+#endif
+
+#ifdef SECURITY_BLANKETS
+#define UseSecurityBlankets() 1
+#else
+#define UseSecurityBlankets() 0
+#endif
+
+#ifdef __MGENERAL_REGS_ONLY__
+#define UseGeneralRegsOnly() 1
+#else
+#define UseGeneralRegsOnly() 0
+#endif
+
+#ifdef TINY
+#define IsTiny() 1
+#else
+#define IsTiny() 0
+#endif
+
+#ifdef __OPTIMIZE__
+#define IsOptimized() 1
+#else
+#define IsOptimized() 0
+#endif
+
+#if defined(__PIE__) || defined(__PIC__)
+#define IsPositionIndependent() 1
+#else
+#define IsPositionIndependent() 0
+#endif
+
+#define SupportsLinux()   ((SUPPORT_VECTOR & LINUX) == LINUX)
+#define SupportsMetal()   ((SUPPORT_VECTOR & METAL) == METAL)
+#define SupportsWindows() ((SUPPORT_VECTOR & WINDOWS) == WINDOWS)
+#define SupportsXnu()     ((SUPPORT_VECTOR & XNU) == XNU)
+#define SupportsFreebsd() ((SUPPORT_VECTOR & FREEBSD) == FREEBSD)
+#define SupportsOpenbsd() ((SUPPORT_VECTOR & OPENBSD) == OPENBSD)
+#define SupportsSystemv() \
+  ((SUPPORT_VECTOR & (LINUX | METAL | XNU | OPENBSD | FREEBSD)) != 0)
+
+#ifndef __ASSEMBLER__
+#define IsLinux()   ((hostos & LINUX) == LINUX)
+#define IsMetal()   ((hostos & METAL) == METAL)
+#define IsWindows() ((hostos & WINDOWS) == WINDOWS)
+#define IsBsd()     ((hostos & (XNU | FREEBSD | OPENBSD)) != 0)
+#define IsXnu()     ((hostos & XNU) == XNU)
+#define IsFreebsd() ((hostos & FREEBSD) == FREEBSD)
+#define IsOpenbsd() ((hostos & OPENBSD) == OPENBSD)
+#else
+/* clang-format off */
+#define IsLinux() $LINUX,hostos(%rip)
+#define IsMetal() $METAL,hostos(%rip)
+#define IsWindows() $WINDOWS,hostos(%rip)
+#define IsBsd() $XNU|FREEBSD|OPENBSD,hostos(%rip)
+#define IsXnu() $XNU,hostos(%rip)
+#define IsFreebsd() $FREEBSD,hostos(%rip)
+#define IsOpenbsd() $OPENBSD,hostos(%rip)
+/* clang-format on */
+#endif
+
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
+#define hostos (__hostos & SUPPORT_VECTOR)
+extern const int __hostos asm("hostos");
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_DCE_H_ */