Add C++ demangling to privileged runtime

Cosmo will now print C++ symbols correctly in --ftrace logs and
backtraces. Doing this required reducing the memory requirement
of the __demangle() function by 3x. This was accomplished using
16-bit indices and 16-bit malloc granularity. That puts a limit
on the longest symbol we can successfully decode, which I think
would be around 6553 characters long, given a 65536-byte buffer

examples/demangle.c

@@ -0,0 +1,67 @@
+#include <assert.h>
+#include <cxxabi.h>
+#include <errno.h>
+#include <stdckdint.h>
+#include <stdio.h>
+#include <string.h>
+#include "libc/assert.h"
+#include "libc/calls/struct/timespec.h"
+#include "libc/cosmo.h"
+#include "libc/runtime/runtime.h"
+#include "libc/stdio/internal.h"
+#include "libc/stdio/stdio.h"
+#include "libc/str/str.h"
+#include "libc/time.h"
+
+void nothing(void) {
+}
+
+void (*barrier)(void) = nothing;
+
+struct timespec now(void) {
+  struct timespec ts;
+  timespec_get(&ts, TIME_UTC);
+  return ts;
+}
+
+long long tonanos(struct timespec x) {
+  return x.tv_sec * 1000000000ll + x.tv_nsec;
+}
+
+struct timespec tub(struct timespec a, struct timespec b) {
+  a.tv_sec -= b.tv_sec;
+  if (a.tv_nsec < b.tv_nsec) {
+    a.tv_nsec += 1000000000;
+    a.tv_sec--;
+  }
+  a.tv_nsec -= b.tv_nsec;
+  return a;
+}
+
+#define BENCH(ITERATIONS, WORK_PER_RUN, CODE)                              \
+  do {                                                                     \
+    struct timespec start = now();                                         \
+    for (int i = 0; i < ITERATIONS; ++i) {                                 \
+      barrier();                                                           \
+      CODE;                                                                \
+    }                                                                      \
+    long long work = WORK_PER_RUN * ITERATIONS;                            \
+    double nanos = (tonanos(tub(now(), start)) + work - 1) / (double)work; \
+    printf("%10g ns %2dx %s\n", nanos, ITERATIONS, #CODE);                 \
+  } while (0)
+
+char got[5632];
+char huge[262144];
+
+__static_yoink("PrintBacktraceUsingSymbols");
+__static_yoink("GetSymbolTable");
+
+int main(int argc, char *argv[]) {
+  ShowCrashReports();
+  const char *sym =
+      "_ZN12_GLOBAL__N_116tinyBLAS_Q0_AVX2ILi0E10block_q4_010block_"
+      "q8_0fE4gemmILi3ELi2ELi0EEEvllll";
+  __demangle(got, sym, sizeof(got));
+  printf("%s\n", got);
+  BENCH(1000, 1, __demangle(got, sym, sizeof(got)));
+}

libc/intrin/asan.c

@@ -1136,10 +1136,7 @@ int __asan_print_trace(void *p) {
     kprintf(" (shadow not mapped?!)");
   }
   for (i = 0; i < ARRAYLEN(e->bt.p) && e->bt.p[i]; ++i) {
-    kprintf("\n%*lx %s", 12, e->bt.p[i],
-            _weaken(GetSymbolByAddr)
-                ? _weaken(GetSymbolByAddr)(e->bt.p[i])
-                : "please __static_yoink(\"GetSymbolByAddr\")");
+    kprintf("\n%*lx %t", 12, e->bt.p[i], e->bt.p[i]);
   }
   return 0;
 }

libc/intrin/kprintf.greg.c

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/intrin/kprintf.h"
 #include "ape/sections.internal.h"
+#include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/fmt/divmod10.internal.h"
@@ -457,6 +458,7 @@ privileged static size_t kformat(char *b, size_t n, const char *fmt,
   const char *abet;
   signed char type;
   const char *s, *f;
+  char cxxbuf[2048];
   struct CosmoTib *tib;
   unsigned long long x;
   unsigned i, j, m, rem, sign, hash, cols, prec;
@@ -804,10 +806,12 @@ privileged static size_t kformat(char *b, size_t n, const char *fmt,
           x = va_arg(va, intptr_t);
           if (_weaken(__symtab) && *_weaken(__symtab) &&
               (idx = _weaken(__get_symbol)(0, x)) != -1) {
-            if (p + 1 <= e)
-              *p++ = '&';
+            /* if (p + 1 <= e) */
+            /*   *p++ = '&'; */
             s = (*_weaken(__symtab))->name_base +
                 (*_weaken(__symtab))->names[idx];
+            if (__is_mangled(s) && __demangle(cxxbuf, s, sizeof(cxxbuf)) != -1)
+              s = cxxbuf;
             goto FormatString;
           }
           base = 4;

libc/log/backtrace3.c

@@ -51,10 +51,9 @@ dontinstrument dontasan int PrintBacktraceUsingSymbols(
   size_t gi;
   intptr_t addr;
   const char *name;
+  char cxxbuf[3000];
   int i, symbol, addend;
-  static char cxxbuf[8192];
   struct Garbages *garbage;
-  static pthread_spinlock_t lock;
   const struct StackFrame *frame;
   (void)gi;
   if (!bp)
@@ -92,10 +91,8 @@ dontinstrument dontasan int PrintBacktraceUsingSymbols(
       addend = 0;
     }
     if ((name = __get_symbol_name(st, symbol)) && __is_mangled(name)) {
-      pthread_spin_lock(&lock);
       __demangle(cxxbuf, name, sizeof(cxxbuf));
       kprintf("%012lx %lx %s%+d\n", frame, addr, cxxbuf, addend);
-      pthread_spin_unlock(&lock);
       name = cxxbuf;
     } else {
       kprintf("%012lx %lx %s%+d\n", frame, addr, name, addend);

libc/mem/alg.h

@@ -8,10 +8,10 @@ void *bsearch_r(const void *, const void *, size_t, size_t,
                 int (*)(const void *, const void *, void *), void *)
     paramsnonnull((1, 2, 5)) nosideeffect;
 void djbsort(int32_t *, size_t) libcesque;
-void qsort3(void *, size_t, size_t, int (*)(const void *, const void *))
-    paramsnonnull();
-void qsort(void *, size_t, size_t, int (*)(const void *, const void *))
-    paramsnonnull();
+void qsort3(void *, size_t, size_t,
+            int (*)(const void *, const void *)) libcesque paramsnonnull();
+void qsort(void *, size_t, size_t,
+           int (*)(const void *, const void *)) libcesque paramsnonnull();
 void qsort_r(void *, size_t, size_t,
              int (*)(const void *, const void *, void *), void *)
     paramsnonnull((1, 4));

libc/runtime/hog.py

@@ -1,2 +0,0 @@
-for i, c in enumerate("Asia/Kolkata"):
-  print("buf[%d] = '%c';" % (i, c))

libc/runtime/quick_exit.c

@@ -21,6 +21,12 @@
 
 void __funcs_on_quick_exit(void);
 
+/**
+ * Exits process faster.
+ *
+ * @param exitcode is masked with 255
+ * @noreturn
+ */
 wontreturn void quick_exit(int code) {
   if (_weaken(__funcs_on_quick_exit))
     _weaken(__funcs_on_quick_exit)();

libc/str/BUILD.mk

@@ -100,6 +100,10 @@ $(LIBC_STR_A_OBJS): private					\
 			-Wframe-larger-than=4096		\
 			-Walloca-larger-than=4096
 
+o/$(MODE)/libc/str/demangle.o: private				\
+		OVERRIDE_CFLAGS +=				\
+			-ffreestanding
+
 LIBC_STR_LIBS = $(foreach x,$(LIBC_STR_ARTIFACTS),$($(x)))
 LIBC_STR_SRCS = $(foreach x,$(LIBC_STR_ARTIFACTS),$($(x)_SRCS))
 LIBC_STR_HDRS = $(foreach x,$(LIBC_STR_ARTIFACTS),$($(x)_HDRS))

test/libc/intrin/kprintf_test.c

@@ -215,9 +215,9 @@ TEST(ksnprintf, testSymbols) {
   hassymbols = GetSymbolTable();
   ksnprintf(b[0], 32, "%t", strlen);
   if (hassymbols) {
-    ASSERT_STREQ("&strlen", b[0]);
+    ASSERT_STREQ("strlen", b[0]);
   } else {
-    ksnprintf(b[1], 32, "&%lx", strlen);
+    ksnprintf(b[1], 32, "%lx", strlen);
     ASSERT_STREQ(b[1], b[0]);
   }
 }

test/libcxx/BUILD.mk

@@ -15,6 +15,7 @@ TEST_LIBCXX_DIRECTDEPS =				\
 	LIBC_CALLS					\
 	LIBC_INTRIN					\
 	LIBC_LOG					\
+	LIBC_MEM					\
 	LIBC_NEXGEN32E					\
 	LIBC_RUNTIME					\
 	LIBC_STDIO					\
@@ -22,6 +23,8 @@ TEST_LIBCXX_DIRECTDEPS =				\
 	LIBC_THREAD					\
 	LIBC_TINYMATH					\
 	THIRD_PARTY_LIBCXX				\
+	THIRD_PARTY_LIBCXXABI				\
+	THIRD_PARTY_LIBUNWIND				\
 	THIRD_PARTY_OPENMP
 
 TEST_LIBCXX_DEPS :=					\
@@ -39,7 +42,7 @@ o/$(MODE)/test/libcxx/%.dbg:				\
 		$(APE_NO_MODIFY_SELF)
 	@$(APELINK)
 
-$(TEST_LIBCXX_OBJS): private CCFLAGS += -fexceptions -frtti
+$(TEST_LIBCXX_OBJS): private OVERRIDE_CXXFLAGS += -fexceptions -frtti
 
 o/$(MODE)/test/libcxx/openmp_test.o: private CXXFLAGS += -fopenmp
 o/$(MODE)/test/libcxx/openmp_test.runs: private QUOTA += -C100

test/libcxx/cexception_test.cc

@@ -1,7 +1,7 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
+/*-*-mode:c++;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8-*-│
+│ vi: set et ft=c++ ts=2 sts=2 sw=2 fenc=utf-8                             :vi │
 ╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│ Copyright 2024 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         │
@@ -16,26 +16,65 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/intrin/strace.internal.h"
-#include "libc/intrin/weaken.h"
-#include "libc/runtime/internal.h"
+#include "libc/mem/alg.h"
+#include "libc/mem/mem.h"
 #include "libc/runtime/runtime.h"
-#include "libc/stdio/stdio.h"
 
-/**
- * Exits process faster.
- *
- * @param exitcode is masked with 255
- * @noreturn
- */
-wontreturn void quick_exit(int exitcode) {
-  const uintptr_t *p;
-  STRACE("quick_exit(%d)", exitcode);
-  if (_weaken(fflush)) {
-    _weaken(fflush)(0);
+// this dontthrow keyword SHOULD break this test. it's probably passing
+// because we're currently using SjLj exceptions. the day we can change
+// things, remove `dontthrow` and this test will still be a useful help
+extern "C" dontthrow void qsort_(void *, size_t, size_t,
+                                 int (*)(const void *,
+                                         const void *)) asm("qsort");
+
+struct Resource {
+  char *p;
+  Resource() {
+    p = new char;
   }
-  for (p = __fini_array_end; p > __fini_array_start;) {
-    ((void (*)(void))(*--p))();
+  ~Resource() {
+    delete p;
   }
-  _Exit(exitcode);
+};
+
+void Poke(char *p) {
+  *p = 1;
+}
+void (*pPoke)(char *) = Poke;
+
+void Throw(void) {
+  throw 42;
+}
+void (*pThrow)(void) = Throw;
+
+int cmp(const void *x, const void *y) {
+  Resource r;
+  pPoke(r.p);
+  if (*r.p)
+    pThrow();
+  exit(5);
+}
+
+int A[3] = {3, 2, 1};
+int Work(void) {
+  Resource r;
+  pPoke(r.p);
+  qsort_(A, 3, sizeof(int), cmp);
+  return A[0];
+}
+int (*pWork)(void) = Work;
+
+int main(int argc, char *argv[]) {
+  try {
+    Resource r;
+    if (pWork() != 1)
+      return 1;
+    pPoke(r.p);
+    if (r.p)
+      return 2;
+  } catch (int e) {
+    if (e != 42)
+      return 3;
+  }
+  CheckForMemoryLeaks();
 }

tool/emacs/cosmo-c-builtins.el

@@ -45,7 +45,8 @@
          '("__builtin_va_list"))
 
         (gcc-builtin-functions
-         '("__builtin_va_start"
+         '("__builtin_strlen"
+           "__builtin_va_start"
            "__builtin_va_arg"
            "__builtin_va_end"
            "__builtin_add_overflow"