Reduce mandatory stack rss by 256kb

ape/aarch64.lds

@@ -280,6 +280,8 @@ SECTIONS {
 
 ape_stack_vaddr = DEFINED(ape_stack_vaddr) ? ape_stack_vaddr : 0x700000000000;
 ape_stack_memsz = DEFINED(ape_stack_memsz) ? ape_stack_memsz : 8 * 1024 * 1024;
+ape_stack_align = DEFINED(ape_stack_align) ? ape_stack_align : 16;
+ape_stack_round = -ape_stack_align;
 
 _tls_size = _tbss_end - _tdata_start;
 _tdata_size = _tdata_end - _tdata_start;

ape/ape.lds

@@ -585,7 +585,8 @@ ape_stack_vaddr = DEFINED(ape_stack_vaddr) ? ape_stack_vaddr : 0x700000000000;
 ape_stack_paddr = ape_ram_paddr + ape_ram_filesz;
 ape_stack_filesz = 0;
 ape_stack_memsz = DEFINED(ape_stack_memsz) ? ape_stack_memsz : 8 * 1024 * 1024;
-ape_stack_align = 16;
+ape_stack_align = DEFINED(ape_stack_align) ? ape_stack_align : 16;
+ape_stack_round = -ape_stack_align;
 
 ape_note_offset = ape_cod_offset + (ape_note - ape_cod_vaddr);
 ape_note_filesz = ape_note_end - ape_note;

libc/crt/crt.S

@@ -68,14 +68,12 @@ _start:
 	mov	%rsp,__oldstack(%rip)
 	mov	%rdx,__envp(%rip)
 
-//	setup backtraces
+//	setup stack
 	xor	%ebp,%ebp
+	and	$ape_stack_round,%rsp
 
-//	make process stack (8mb) follow thread stack (256kb) alignment
-	and	$-(256*1024),%rsp
-
-#if SupportsWindows()
-//	make win32 imps noop
+#if SupportsWindows() && !IsTiny()
+//	make win32 imps crash
 	.weak	ape_idata_iat
 	.weak	ape_idata_iatend
 	.weak	__oops_win32
@@ -122,9 +120,12 @@ _start:
 //	this is the first argument to cosmo() below
 	mov	x0,sp
 
-//	make process stack (8mb) conform to thread stack (256kb) alignment
-	mov	x1,sp
-	and	sp,x1,-(256*1024)
+//	setup the stack
+	mov	x29,#0
+	mov	x30,#0
+	ldr	x1,=ape_stack_round
+	and	x1,x0,x1
+	mov	sp,x1
 
 //	second arg shall be struct Syslib passed by ape-m1.c
 //	used to talk to apple's authoritarian libraries

libc/runtime/internal.h

@@ -38,7 +38,6 @@ void __enable_tls(void);
 void *__cxa_finalize(void *);
 void __stack_chk_fail(void) wontreturn relegated;
 void __stack_chk_fail_local(void) wontreturn relegated;
-void _jmpstack(void *, void *, ...) wontreturn;
 long _setstack(void *, void *, ...);
 int GetDosArgv(const char16_t *, char *, size_t, char **, size_t);
 int GetDosEnviron(const char16_t *, char *, size_t, char **, size_t);

libc/runtime/jmpstack.S

@@ -1,37 +0,0 @@
-/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
-│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/macros.internal.h"
-
-//	Switches stack.
-//
-//	@param	rdi is new rsp, passed as malloc(size) + size
-//	@param	rsi is function to call in new stack space
-//	@param	rdx,rcx,r8,r9 get passed as args to rsi
-//	@noreturn
-_jmpstack:
-	mov	%rdi,%rsp
-	mov	%rsi,%rax
-	mov	%rdx,%rdi
-	mov	%rcx,%rsi
-	mov	%r8,%rdx
-	mov	%r9,%rcx
-	xor	%ebp,%ebp
-	call	*%rax
-	.unreachable
-	.endfn	_jmpstack,globl,hidden

libc/runtime/stack.h

@@ -18,46 +18,18 @@
 #define GetGuardSize() 16384
 
 /**
- * Tunes APE stack maximum size.
+ * Align APE main thread stack at startup.
  *
- * The bottom-most page will be protected to ensure your stack does not
- * magically grow beyond this value. It's possible to detect stack
- * overflows, by calling `ShowCrashReports()`. Your stack size must be a
- * power of two; the linker will check this.
+ * You need this in your main program module:
  *
- * If you want to know how much stack your programs needs, then
+ *     STATIC_STACK_ALIGN(GetStackSize());
  *
- *     __static_yoink("stack_usage_logging");
- *
- * will install an atexit() handler that appends to `o/$MODE/stack.log`
- *
- * @see libc/sysv/systemfive.S
- * @see ape/ape.lds
+ * If you want to use GetStackAddr() and HaveStackMemory() safely on
+ * your main thread in your process. It causes crt.S to waste a tiny
+ * amount of memory to ensure those macros go extremely fast.
  */
-#define STATIC_STACK_SIZE(BYTES) \
-  _STACK_SYMBOL("ape_stack_memsz", _STACK_STRINGIFY(BYTES) _STACK_EXTRA)
-
-/**
- * Tunes APE stack virtual address.
- *
- * This value must be aligned according to your stack size, and that's
- * checked by your linker script. This defaults to `0x700000000000` so
- *
- * 1. It's easy to see how close you are to the bottom
- * 2. The linker script error is unlikely to happen
- *
- * This macro will be respected, with two exceptions
- *
- * 1. In MODE=tiny the operating system provided stack is used instead
- * 2. Windows 7 doesn't support 64-bit addresses, so we'll instead use
- *    `0x10000000 - GetStackSize()` as the stack address
- *
- * @see libc/sysv/systemfive.S
- * @see libc/nt/winmain.greg.c
- * @see ape/ape.lds
- */
-#define STATIC_STACK_ADDR(ADDR) \
-  _STACK_SYMBOL("ape_stack_vaddr", _STACK_STRINGIFY(ADDR))
+#define STATIC_STACK_ALIGN(BYTES) \
+  _STACK_SYMBOL("ape_stack_align", _STACK_STRINGIFY(BYTES) _STACK_EXTRA)
 
 /**
  * Makes program stack executable if declared, e.g.
@@ -78,7 +50,7 @@
 
 #define _STACK_STRINGIFY(ADDR) #ADDR
 #define _STACK_SYMBOL(NAME, VALUE)       \
-  asm(".equ\t" NAME "," VALUE "\n\t" \
+  __asm__(".equ\t" NAME "," VALUE "\n\t" \
           ".globl\t" NAME)
 
 #ifdef __SANITIZE_ADDRESS__
@@ -95,29 +67,71 @@ extern char ape_stack_memsz[] __attribute__((__weak__));
 extern char ape_stack_align[] __attribute__((__weak__));
 
 /**
- * Returns address of bottom of stack.
+ * Returns address of bottom of current stack.
  *
- * This takes into consideration threads and sigaltstack. This is
- * implemented as a fast pure expression, since we're able to make the
- * assumption that stack sizes are two powers and aligned. This is
- * thanks to (1) the linker script checks the statically chosen sizes,
- * and (2) the mmap() address picker will choose aligned addresses when
- * the provided size is a two power.
+ * This always works on threads. If you want it to work on the main
+ * process too, then you'll need STATIC_STACK_ALIGN(GetStackSize())
+ * which will burn O(256kb) of memory to ensure thread invariants.
  */
 #define GetStackAddr() \
   (((intptr_t)__builtin_frame_address(0) - 1) & -GetStackSize())
 
 #define GetStaticStackSize() ((uintptr_t)ape_stack_memsz)
 
+/**
+ * Returns true if at least `n` bytes of stack are available.
+ *
+ * This always works on threads. If you want it to work on the main
+ * process too, then you'll need STATIC_STACK_ALIGN(GetStackSize())
+ * which will burn O(256kb) of memory to ensure thread invariants,
+ * which make this check exceedingly fast.
+ */
+#define HaveStackMemory(n)                 \
+  ((intptr_t)__builtin_frame_address(0) >= \
+   GetStackAddr() + GetGuardSize() + (n))
+
+/**
+ * Extends stack memory by poking large allocations.
+ *
+ * This can be particularly useful depending on how your system
+ * implements guard pages. For example, Windows can make stacks
+ * that aren't fully committed, in which case there's only 4096
+ * bytes of grows-down guard pages made by portable executable.
+ * If you alloca() more memory than that, you should call this,
+ * since it'll not only ensure stack overflows are detected, it
+ * will also trigger the stack to grow down safely.
+ */
+__funline void CheckLargeStackAllocation(void *p, ssize_t n) {
+  for (; n > 0; n -= 4096) {
+    ((char *)p)[n - 1] = 0;
+  }
+}
+
+void *NewCosmoStack(void) vallocesque;
+int FreeCosmoStack(void *) libcesque;
+
+/**
+ * Tunes stack size of main thread on Windows.
+ *
+ * On UNIX systems use `RLIMIT_STACK` to tune the main thread size.
+ */
+#define STATIC_STACK_SIZE(BYTES) \
+  _STACK_SYMBOL("ape_stack_memsz", _STACK_STRINGIFY(BYTES) _STACK_EXTRA)
+
+/**
+ * Tunes main thread stack address on Windows.
+ */
+#define STATIC_STACK_ADDR(ADDR) \
+  _STACK_SYMBOL("ape_stack_vaddr", _STACK_STRINGIFY(ADDR))
+
 #ifdef __x86_64__
 /**
- * Returns preferred bottom address of stack.
+ * Returns preferred bottom address of main thread stack.
  *
- * This is the stakc address of the main process. The only time that
- * isn't guaranteed to be the case is in MODE=tiny, since it doesn't
- * link the code for stack creation at startup. This generally isn't
- * problematic, since MODE=tiny doesn't use any of the runtime codes
- * which want the stack to be cheaply knowable, e.g. ftrace, kprintf
+ * On UNIX systems we favor the system provided stack, so this only
+ * really applies to Windows. It's configurable at link time. It is
+ * needed because polyfilling fork requires that we know, precicely
+ * where the stack memory begins and ends.
  */
 #define GetStaticStackAddr(ADDEND)          \
   ({                                        \
@@ -132,25 +146,6 @@ extern char ape_stack_align[] __attribute__((__weak__));
 #define GetStaticStackAddr(ADDEND) (GetStackAddr() + ADDEND)
 #endif
 
-/**
- * Returns true if at least `n` bytes of stack are available.
- */
-#define HaveStackMemory(n)                 \
-  ((intptr_t)__builtin_frame_address(0) >= \
-   GetStackAddr() + GetGuardSize() + (n))
-
-/**
- * Extends stack memory by poking large allocations.
- */
-forceinline void CheckLargeStackAllocation(void *p, ssize_t n) {
-  for (; n > 0; n -= 4096) {
-    ((char *)p)[n - 1] = 0;
-  }
-}
-
-void *NewCosmoStack(void) vallocesque;
-int FreeCosmoStack(void *) libcesque;
-
 COSMOPOLITAN_C_END_
 #endif /* GNU ELF */
 #endif /* _COSMO_SOURCE */

libc/runtime/stackuse.c

@@ -27,6 +27,10 @@
 #include "libc/str/str.h"
 #include "libc/sysv/consts/o.h"
 
+// TODO(jart): Delete?
+
+STATIC_STACK_ALIGN(GetStackSize());
+
 static char stacklog[1024];
 
 dontasan size_t GetStackUsage(char *s, size_t n) {

libc/runtime/winmain.greg.c

@@ -77,7 +77,10 @@ __msabi extern typeof(SetStdHandle) *const __imp_SetStdHandle;
 __msabi extern typeof(VirtualProtect) *const __imp_VirtualProtect;
 // clang-format on
 
-extern void cosmo(int, char **, char **, long (*)[2]) wontreturn;
+void cosmo(int, char **, char **, long (*)[2]) wontreturn;
+void __switch_stacks(int, char **, char **, long (*)[2],
+                     void (*)(int, char **, char **, long (*)[2]),
+                     intptr_t) wontreturn;
 
 static const signed char kNtStdio[3] = {
     (signed char)kNtStdInputHandle,
@@ -211,8 +214,8 @@ __msabi static textwindows wontreturn void WinInit(const char16_t *cmdline) {
   __envp = &wa->envp[0];
 
   // handover control to cosmopolitan runtime
-  _jmpstack((char *)(stackaddr + (stacksize - sizeof(struct WinArgs))), cosmo,
-            count, wa->argv, wa->envp, wa->auxv);
+  __switch_stacks(count, wa->argv, wa->envp, wa->auxv, cosmo,
+                  stackaddr + (stacksize - sizeof(struct WinArgs)));
 }
 
 __msabi textwindows int64_t WinMain(int64_t hInstance, int64_t hPrevInstance,

libc/tinymath/coshl.c

@@ -112,6 +112,7 @@ long double
 coshl(long double x)
 {
 	long double hi,lo,x2,x4;
+	(void)x4;
 #if LDBL_MANT_DIG == 113
 	double dx2;
 #endif

libc/tinymath/sinhl.c

@@ -108,6 +108,7 @@ long double
 sinhl(long double x)
 {
 	long double hi,lo,x2,x4;
+	(void)x4;
 #if LDBL_MANT_DIG == 113
 	double dx2;
 #endif

libc/tinymath/tanhl.c

@@ -135,6 +135,7 @@ long double
 tanhl(long double x)
 {
 	long double hi,lo,s,x2,x4,z;
+	(void)x4;
 #if LDBL_MANT_DIG == 113
 	double dx2;
 #endif

third_party/lua/lua.main.c

@@ -57,7 +57,7 @@ Lua 5.4.3 (MIT License)\\n\
 Copyright 1994–2021 Lua.org, PUC-Rio.\"");
 asm(".include \"libc/disclaimer.inc\"");
 
-STATIC_STACK_SIZE(0x80000);
+STATIC_STACK_ALIGN(GetStackSize());
 
 #if !defined(LUA_PROGNAME)
 #define LUA_PROGNAME		"lua"

third_party/lua/luac.main.c

@@ -50,7 +50,6 @@ Lua 5.4.3 (MIT License)\\n\
 Copyright 1994–2021 Lua.org, PUC-Rio.\"");
 asm(".include \"libc/disclaimer.inc\"");
 
-
 static void PrintFunction(const Proto* f, int full);
 #define luaU_print	PrintFunction
 

third_party/python/python.c

@@ -4,11 +4,14 @@
 │ Python 3                                                                     │
 │ https://docs.python.org/3/license.html                                       │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/runtime/stack.h"
 #include "third_party/python/Include/yoink.h"
 #include "third_party/python/runpythonmodule.h"
 #include "tool/args/args.h"
 // clang-format off
 
+STATIC_STACK_ALIGN(GetStackSize());
+
 PYTHON_YOINK("xed");
 PYTHON_YOINK("xterm");
 

tool/net/redbean.c

@@ -142,7 +142,7 @@
 
 #pragma GCC diagnostic ignored "-Wunused-variable"
 
-STATIC_STACK_SIZE(0x80000);
+STATIC_STACK_ALIGN(GetStackSize());
 
 __static_yoink("zipos");