Merge "Format code to calculate thread stack and signal stack."
diff --git a/libc/Android.bp b/libc/Android.bp
index 8ec2b92..cbca35f 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -45,6 +45,7 @@
         "-Wall",
         "-Wextra",
         "-Wunused",
+        "-Wno-deprecated-declarations",
 
         // Try to catch typical 32-bit assumptions that break with 64-bit pointers.
         "-Werror=pointer-to-int-cast",
diff --git a/libc/Android.mk b/libc/Android.mk
index ffa8a27..e9ee7fc 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -575,18 +575,15 @@
 libc_common_cflags := \
     -D_LIBC=1 \
     -Wall -Wextra -Wunused \
+    -Wno-deprecated-declarations \
 
-use_clang := $(USE_CLANG_PLATFORM_BUILD)
+use_clang := true
 
 # b/25291096, Clang/llvm compiled libc.so for mips/mips64 failed to boot.
 ifeq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),mips mips64))
   use_clang := false
 endif
 
-ifeq ($(use_clang),)
-  use_clang := true
-endif
-
 # Try to catch typical 32-bit assumptions that break with 64-bit pointers.
 libc_common_cflags += \
     -Werror=pointer-to-int-cast \
diff --git a/libm/include/arm/machine/fenv.h b/libc/arch-arm/include/machine/fenv.h
similarity index 100%
rename from libm/include/arm/machine/fenv.h
rename to libc/arch-arm/include/machine/fenv.h
diff --git a/libm/include/arm64/machine/fenv.h b/libc/arch-arm64/include/machine/fenv.h
similarity index 100%
rename from libm/include/arm64/machine/fenv.h
rename to libc/arch-arm64/include/machine/fenv.h
diff --git a/libm/include/mips/machine/fenv.h b/libc/arch-mips/include/machine/fenv.h
similarity index 100%
rename from libm/include/mips/machine/fenv.h
rename to libc/arch-mips/include/machine/fenv.h
diff --git a/libm/include/i387/machine/fenv.h b/libc/arch-x86/include/machine/fenv.h
similarity index 100%
rename from libm/include/i387/machine/fenv.h
rename to libc/arch-x86/include/machine/fenv.h
diff --git a/libm/include/amd64/machine/fenv.h b/libc/arch-x86_64/include/machine/fenv.h
similarity index 100%
rename from libm/include/amd64/machine/fenv.h
rename to libc/arch-x86_64/include/machine/fenv.h
diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index 1796109..0c9e87b 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -99,6 +99,15 @@
   });
 }
 
+#if !defined(__LP64__)
+static void __check_max_thread_id() {
+  if (gettid() > 65535) {
+    __libc_fatal("Limited by the size of pthread_mutex_t, 32 bit bionic libc only accepts "
+                 "pid <= 65535, but current pid is %d", gettid());
+  }
+}
+#endif
+
 void __libc_init_common(KernelArgumentBlock& args) {
   // Initialize various globals.
   environ = args.envp;
@@ -106,6 +115,10 @@
   __progname = args.argv[0] ? args.argv[0] : "<unknown>";
   __abort_message_ptr = args.abort_message_ptr;
 
+#if !defined(__LP64__)
+  __check_max_thread_id();
+#endif
+
   // Get the main thread from TLS and add it to the thread list.
   pthread_internal_t* main_thread = __get_thread();
   __pthread_internal_add(main_thread);
diff --git a/libm/include/complex.h b/libc/include/complex.h
similarity index 100%
rename from libm/include/complex.h
rename to libc/include/complex.h
diff --git a/libm/include/fenv.h b/libc/include/fenv.h
similarity index 100%
rename from libm/include/fenv.h
rename to libc/include/fenv.h
diff --git a/libm/include/math.h b/libc/include/math.h
similarity index 100%
rename from libm/include/math.h
rename to libc/include/math.h
diff --git a/libc/include/mntent.h b/libc/include/mntent.h
index a190aeb..ab40079 100644
--- a/libc/include/mntent.h
+++ b/libc/include/mntent.h
@@ -25,6 +25,7 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
+
 #ifndef _MNTENT_H_
 #define _MNTENT_H_
 
@@ -33,7 +34,17 @@
 #include <paths.h>  /* for _PATH_MOUNTED */
 
 #define MOUNTED _PATH_MOUNTED
+
 #define MNTTYPE_IGNORE "ignore"
+#define MNTTYPE_NFS "nfs"
+#define MNTTYPE_SWAP "swap"
+
+#define MNTOPT_DEFAULTS "defaults"
+#define MNTOPT_NOAUTO "noauto"
+#define MNTOPT_NOSUID "nosuid"
+#define MNTOPT_RO "ro"
+#define MNTOPT_RW "rw"
+#define MNTOPT_SUID "suid"
 
 struct mntent {
   char* mnt_fsname;
diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index ccfd751..b409ff2 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -285,14 +285,8 @@
 #if !defined(__LP64__)
 
 // Bionic additions that are deprecated even in the 32-bit ABI.
-//
-// TODO: Remove them once chromium_org / NFC have switched over.
-int pthread_cond_timedwait_monotonic_np(pthread_cond_t*, pthread_mutex_t*, const struct timespec*);
-int pthread_cond_timedwait_monotonic(pthread_cond_t*, pthread_mutex_t*, const struct timespec*);
-
-int pthread_cond_timedwait_relative_np(pthread_cond_t*, pthread_mutex_t*, const struct timespec*) /* TODO: __attribute__((deprecated("use pthread_cond_timedwait instead")))*/;
-#define HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE 1 /* TODO: stop defining this to push LP32 off this API sooner. */
-int pthread_cond_timeout_np(pthread_cond_t*, pthread_mutex_t*, unsigned) /* TODO: __attribute__((deprecated("use pthread_cond_timedwait instead")))*/;
+int pthread_cond_timedwait_relative_np(pthread_cond_t*, pthread_mutex_t*, const struct timespec*) __attribute__((deprecated("use pthread_cond_timedwait instead")));
+int pthread_cond_timeout_np(pthread_cond_t*, pthread_mutex_t*, unsigned) __attribute__((deprecated("use pthread_cond_timedwait instead")));
 
 int pthread_mutex_lock_timeout_np(pthread_mutex_t*, unsigned) __attribute__((deprecated("use pthread_mutex_timedlock instead")));
 
diff --git a/libc/include/sys/param.h b/libc/include/sys/param.h
index e64d6ce..5d2248f 100644
--- a/libc/include/sys/param.h
+++ b/libc/include/sys/param.h
@@ -31,6 +31,8 @@
 #include <limits.h>
 #include <linux/param.h>
 
+#define DEV_BSIZE 512
+
 #define MAXPATHLEN  PATH_MAX
 #define MAXSYMLINKS 8
 
diff --git a/libc/include/sys/stat.h b/libc/include/sys/stat.h
index 257ded0..86668f6 100644
--- a/libc/include/sys/stat.h
+++ b/libc/include/sys/stat.h
@@ -135,6 +135,12 @@
 #define DEFFILEMODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH) /* 0666 */
 #endif
 
+#if defined(__USE_BSD) || defined(__USE_GNU)
+#define S_IREAD S_IRUSR
+#define S_IWRITE S_IWUSR
+#define S_IEXEC S_IXUSR
+#endif
+
 extern int chmod(const char*, mode_t);
 extern int fchmod(int, mode_t);
 extern int mkdir(const char*, mode_t);
diff --git a/libc/include/sys/types.h b/libc/include/sys/types.h
index 217fd60..a422261 100644
--- a/libc/include/sys/types.h
+++ b/libc/include/sys/types.h
@@ -66,6 +66,8 @@
 typedef __kernel_ino_t __ino_t;
 typedef __ino_t ino_t;
 
+typedef uint64_t ino64_t;
+
 typedef uint32_t __nlink_t;
 typedef __nlink_t nlink_t;
 
diff --git a/libm/amd64/fenv.c b/libm/amd64/fenv.c
index 4b24ff9..9edaf88 100755
--- a/libm/amd64/fenv.c
+++ b/libm/amd64/fenv.c
@@ -28,7 +28,14 @@
  */
 
 #include <fenv.h>
-#include <machine/fpu.h>
+
+/*
+ * The i387 defaults to Intel extended precision mode and round to nearest,
+ * with all exceptions masked.
+ */
+#define	__INITIAL_NPXCW__	0x037f
+#define __INITIAL_MXCSR__ 	0x1f80
+#define __INITIAL_MXCSR_MASK__	0xffbf
 
 #define SSE_MASK_SHIFT 7
 
diff --git a/libm/i387/fenv.c b/libm/i387/fenv.c
index f64f8dc..64c2b7a 100644
--- a/libm/i387/fenv.c
+++ b/libm/i387/fenv.c
@@ -28,12 +28,31 @@
 
 #include <sys/cdefs.h>
 #include <sys/types.h>
-#include "npx.h"
 #include "fenv.h"
 
 #define ROUND_MASK   (FE_TONEAREST | FE_DOWNWARD | FE_UPWARD | FE_TOWARDZERO)
 
 /*
+ * The hardware default control word for i387's and later coprocessors is
+ * 0x37F, giving:
+ *
+ *	round to nearest
+ *	64-bit precision
+ *	all exceptions masked.
+ *
+ * We modify the affine mode bit and precision bits in this to give:
+ *
+ *	affine mode for 287's (if they work at all) (1 in bitfield 1<<12)
+ *	53-bit precision (2 in bitfield 3<<8)
+ *
+ * 64-bit precision often gives bad results with high level languages
+ * because it makes the results of calculations depend on whether
+ * intermediate values are stored in memory or in FPU registers.
+ */
+#define	__INITIAL_NPXCW__	0x127F
+#define	__INITIAL_MXCSR__	0x1F80
+
+/*
  * As compared to the x87 control word, the SSE unit's control word
  * has the rounding control bits offset by 3 and the exception mask
  * bits offset by 7.
diff --git a/libm/i387/npx.h b/libm/i387/npx.h
deleted file mode 100644
index 38c2add..0000000
--- a/libm/i387/npx.h
+++ /dev/null
@@ -1,160 +0,0 @@
-/*-
- * Copyright (c) 1990 The Regents of the University of California.
- * All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * William Jolitz.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *	from: @(#)npx.h	5.3 (Berkeley) 1/18/91
- * $FreeBSD: src/sys/i386/include/npx.h,v 1.29.2.1 2006/07/01 00:57:55 davidxu Exp $
- */
-
-/*
- * 287/387 NPX Coprocessor Data Structures and Constants
- * W. Jolitz 1/90
- */
-
-#ifndef _MACHINE_NPX_H_
-#define	_MACHINE_NPX_H_
-
-/* Environment information of floating point unit */
-struct env87 {
-	long	en_cw;		/* control word (16bits) */
-	long	en_sw;		/* status word (16bits) */
-	long	en_tw;		/* tag word (16bits) */
-	long	en_fip;		/* floating point instruction pointer */
-	u_short	en_fcs;		/* floating code segment selector */
-	u_short	en_opcode;	/* opcode last executed (11 bits ) */
-	long	en_foo;		/* floating operand offset */
-	long	en_fos;		/* floating operand segment selector */
-};
-
-/* Contents of each floating point accumulator */
-struct fpacc87 {
-#ifdef dontdef /* too unportable */
-	u_long	fp_mantlo;	/* mantissa low (31:0) */
-	u_long	fp_manthi;	/* mantissa high (63:32) */
-	int	fp_exp:15;	/* exponent */
-	int	fp_sgn:1;	/* mantissa sign */
-#else
-	u_char	fp_bytes[10];
-#endif
-};
-
-/* Floating point context */
-struct save87 {
-	struct	env87 sv_env;	/* floating point control/status */
-	struct	fpacc87	sv_ac[8];	/* accumulator contents, 0-7 */
-	u_char	sv_pad0[4];	/* padding for (now unused) saved status word */
-	/*
-	 * Bogus padding for emulators.  Emulators should use their own
-	 * struct and arrange to store into this struct (ending here)
-	 * before it is inspected for ptracing or for core dumps.  Some
-	 * emulators overwrite the whole struct.  We have no good way of
-	 * knowing how much padding to leave.  Leave just enough for the
-	 * GPL emulator's i387_union (176 bytes total).
-	 */
-	u_char	sv_pad[64];	/* padding; used by emulators */
-};
-
-struct  envxmm {
-	u_int16_t	en_cw;		/* control word (16bits) */
-	u_int16_t	en_sw;		/* status word (16bits) */
-	u_int16_t	en_tw;		/* tag word (16bits) */
-	u_int16_t	en_opcode;	/* opcode last executed (11 bits ) */
-	u_int32_t	en_fip;		/* floating point instruction pointer */
-	u_int16_t	en_fcs;		/* floating code segment selector */
-	u_int16_t	en_pad0;	/* padding */
-	u_int32_t	en_foo;		/* floating operand offset */
-	u_int16_t	en_fos;		/* floating operand segment selector */
-	u_int16_t	en_pad1;	/* padding */
-	u_int32_t	en_mxcsr;	/* SSE sontorol/status register */
-	u_int32_t	en_mxcsr_mask;	/* valid bits in mxcsr */
-};
-
-/* Contents of each SSE extended accumulator */
-struct  xmmacc {
-	u_char	xmm_bytes[16];
-};
-
-struct  savexmm {
-	struct	envxmm	sv_env;
-	struct {
-		struct fpacc87	fp_acc;
-		u_char		fp_pad[6];      /* padding */
-	} sv_fp[8];
-	struct xmmacc	sv_xmm[8];
-	u_char sv_pad[224];
-} __aligned(16);
-
-union	savefpu {
-	struct	save87	sv_87;
-	struct	savexmm	sv_xmm;
-};
-
-/*
- * The hardware default control word for i387's and later coprocessors is
- * 0x37F, giving:
- *
- *	round to nearest
- *	64-bit precision
- *	all exceptions masked.
- *
- * We modify the affine mode bit and precision bits in this to give:
- *
- *	affine mode for 287's (if they work at all) (1 in bitfield 1<<12)
- *	53-bit precision (2 in bitfield 3<<8)
- *
- * 64-bit precision often gives bad results with high level languages
- * because it makes the results of calculations depend on whether
- * intermediate values are stored in memory or in FPU registers.
- */
-#define	__INITIAL_NPXCW__	0x127F
-#define	__INITIAL_MXCSR__	0x1F80
-
-#ifdef _KERNEL
-
-#define	IO_NPX		0x0F0		/* Numeric Coprocessor */
-#define	IO_NPXSIZE	16		/* 80387/80487 NPX registers */
-
-#define	IRQ_NPX		13
-
-/* full reset on some systems, NOP on others */
-#define npx_full_reset() outb(IO_NPX + 1, 0)
-
-int	npxdna(void);
-void	npxdrop(void);
-void	npxexit(struct thread *td);
-int	npxformat(void);
-int	npxgetregs(struct thread *td, union savefpu *addr);
-void	npxinit(u_short control);
-void	npxsave(union savefpu *addr);
-void	npxsetregs(struct thread *td, union savefpu *addr);
-int	npxtrap(void);
-#endif
-
-#endif /* !_MACHINE_NPX_H_ */
diff --git a/libm/include/amd64/machine/fpu.h b/libm/include/amd64/machine/fpu.h
deleted file mode 100644
index bda8f05..0000000
--- a/libm/include/amd64/machine/fpu.h
+++ /dev/null
@@ -1,65 +0,0 @@
-/*	$OpenBSD: fpu.h,v 1.9 2011/03/23 16:54:34 pirofti Exp $	*/
-/*	$NetBSD: fpu.h,v 1.1 2003/04/26 18:39:40 fvdl Exp $	*/
-
-#ifndef	_MACHINE_FPU_H_
-#define	_MACHINE_FPU_H_
-
-#include <sys/types.h>
-
-/*
- * amd64 only uses the extended save/restore format used
- * by fxsave/fsrestore, to always deal with the SSE registers,
- * which are part of the ABI to pass floating point values.
- * Must be stored in memory on a 16-byte boundary.
- */
-
-struct fxsave64 {
-	u_int16_t  fx_fcw;
-	u_int16_t  fx_fsw;
-	u_int8_t   fx_ftw;
-	u_int8_t   fx_unused1;
-	u_int16_t  fx_fop;
-	u_int64_t  fx_rip;
-	u_int64_t  fx_rdp;
-	u_int32_t  fx_mxcsr;
-	u_int32_t  fx_mxcsr_mask;
-	u_int64_t  fx_st[8][2];   /* 8 normal FP regs */
-	u_int64_t  fx_xmm[16][2]; /* 16 SSE2 registers */
-	u_int8_t   fx_unused3[96];
-} __packed;
-
-struct savefpu {
-	struct fxsave64 fp_fxsave;	/* see above */
-	u_int16_t fp_ex_sw;		/* saved status from last exception */
-	u_int16_t fp_ex_tw;		/* saved tag from last exception */
-};
-
-/*
- * The i387 defaults to Intel extended precision mode and round to nearest,
- * with all exceptions masked.
- */
-#define	__INITIAL_NPXCW__	0x037f
-#define __INITIAL_MXCSR__ 	0x1f80
-#define __INITIAL_MXCSR_MASK__	0xffbf
-
-#ifdef _KERNEL
-/*
- * XXX
- */
-struct trapframe;
-struct cpu_info;
-
-extern uint32_t	fpu_mxcsr_mask;
-
-void fpuinit(struct cpu_info *);
-void fpudrop(void);
-void fpudiscard(struct proc *);
-void fputrap(struct trapframe *);
-void fpusave_proc(struct proc *, int);
-void fpusave_cpu(struct cpu_info *, int);
-void fpu_kernel_enter(void);
-void fpu_kernel_exit(void);
-
-#endif
-
-#endif /* _MACHINE_FPU_H_ */
diff --git a/linker/linker_mips.cpp b/linker/linker_mips.cpp
index 6130066..8520c17 100644
--- a/linker/linker_mips.cpp
+++ b/linker/linker_mips.cpp
@@ -256,18 +256,10 @@
 
   // FP ABI-variant compatibility checks for MIPS o32 ABI
   if (abiflags == nullptr) {
-    // Old compilers and some translators don't emit the new abiflags section.
-    const char* filename = get_realpath();
-    size_t len = strlen(filename);
-    if (len > 4 && (strcmp(filename+len-4, ".dex") == 0 ||
-                    strcmp(filename+len-4, ".oat") == 0   )) {
-      // Assume dex2oat is compatible with target
-      mips_fpabi = MIPS_ABI_FP_XX;
-    } else {
-      // Old Android compilers used -mfp32 -mdouble-float -modd-spreg defaults,
-      //   ie FP32 aka DOUBLE, using FR=0 mode fpregs & odd single-prec fpregs
-      mips_fpabi = MIPS_ABI_FP_DOUBLE;
-    }
+    // Old compilers lack the new abiflags section.
+    // These compilers used -mfp32 -mdouble-float -modd-spreg defaults,
+    //   ie FP32 aka DOUBLE, using odd-numbered single-prec regs
+    mips_fpabi = MIPS_ABI_FP_DOUBLE;
   } else {
     mips_fpabi = abiflags->fp_abi;
     if ( (abiflags->flags1 & MIPS_AFL_FLAGS1_ODDSPREG)
diff --git a/tests/complex_test.cpp b/tests/complex_test.cpp
index 710912a..3b8e682 100644
--- a/tests/complex_test.cpp
+++ b/tests/complex_test.cpp
@@ -18,7 +18,7 @@
 
 // libc++ actively gets in the way of including <complex.h> from C++, so we
 // have to be naughty.
-#include <../libm/include/complex.h>
+#include <../libc/include/complex.h>
 
 // (libc++ also seems to have really bad implementations of its own that ignore
 // the intricacies of floating point math.)
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index 81479d5..1123163 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -211,8 +211,6 @@
   dlclose(handle);
 }
 
-// ifuncs are only supported on intel and arm64 for now
-#if defined (__aarch64__) || defined(__i386__) || defined(__x86_64__)
 TEST(dlfcn, ifunc) {
   typedef const char* (*fn_ptr)();
 
@@ -256,7 +254,6 @@
   ASSERT_STREQ("true", is_ctor_called());
   dlclose(handle);
 }
-#endif
 
 TEST(dlfcn, dlopen_check_relocation_dt_needed_order) {
   // This is the structure of the test library and
diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk
index 506d6f2..a903732 100644
--- a/tests/libs/Android.mk
+++ b/tests/libs/Android.mk
@@ -346,25 +346,14 @@
 libtest_ifunc_src_files := \
     dlopen_testlib_ifunc.c
 
+# TODO(dimitry): clang does not support ifunc attribute
 libtest_ifunc_clang_host := false
+libtest_ifunc_clang_target := false
+
 module := libtest_ifunc
 build_target := SHARED_LIBRARY
 
-build_type := host
-include $(TEST_PATH)/Android.build.mk
-
-ifeq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),arm64 x86 x86_64))
-    ifeq ($(TARGET_ARCH),arm64)
-      libtest_ifunc_multilib := 64
-      # TODO: This is a workaround - remove it once gcc
-      # removes its Android ifunc checks
-      libtest_ifunc_cflags := -mglibc
-    endif
-
-    build_type := target
-    libtest_ifunc_clang_target := false
-    include $(TEST_PATH)/Android.build.mk
-endif
+include $(LOCAL_PATH)/Android.build.testlib.mk
 
 # -----------------------------------------------------------------------------
 # Library used by atexit tests
diff --git a/tests/stack_protector_test_helper.cpp b/tests/stack_protector_test_helper.cpp
index 34f3c77..3f15a12 100644
--- a/tests/stack_protector_test_helper.cpp
+++ b/tests/stack_protector_test_helper.cpp
@@ -19,6 +19,8 @@
   char buf[128];
   // We can't use memset here because it's fortified, and we want to test
   // the line of defense *after* that.
-  char* p = buf;
-  while ((p - buf) < static_cast<int>(sizeof(buf) + sizeof(void*))) *p++ = '\0';
+  // Without volatile, the generic x86/x86-64 targets don't write to the stack.
+  volatile char* p = buf;
+  int size = static_cast<int>(sizeof(buf) + 1);
+  while ((p - buf) < size) *p++ = '\0';
 }
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 79b0fa5..841641f 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -58,14 +58,24 @@
 TEST(UNISTD_TEST, brk) {
   void* initial_break = get_brk();
 
-  // The kernel aligns the break to a page.
   void* new_break = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(initial_break) + 1);
-  ASSERT_EQ(0, brk(new_break));
-  ASSERT_GE(get_brk(), new_break);
+  int ret = brk(new_break);
+  if (ret == -1) {
+    ASSERT_EQ(errno, ENOMEM);
+  } else {
+    ASSERT_EQ(0, ret);
+    ASSERT_GE(get_brk(), new_break);
+  }
 
+  // Expand by a full page to force the mapping to expand
   new_break = page_align(reinterpret_cast<uintptr_t>(initial_break) + sysconf(_SC_PAGE_SIZE));
-  ASSERT_EQ(0, brk(new_break));
-  ASSERT_EQ(get_brk(), new_break);
+  ret = brk(new_break);
+  if (ret == -1) {
+    ASSERT_EQ(errno, ENOMEM);
+  } else {
+    ASSERT_EQ(0, ret);
+    ASSERT_EQ(get_brk(), new_break);
+  }
 }
 
 TEST(UNISTD_TEST, brk_ENOMEM) {