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e83103c805
Fuchsia enables safe-stack by default in the compiler. Disable it for the test function so that a candidate RSP value can be found by using the value of locals on the stack. (This also reduces the function prolog size sufficiently for the PC comparison to work, otherwise it required 75 bytes for the delta comparison.) Bug: crashpad:196 Change-Id: I2adbcee93c90dbc415309b79e3d16e9c4635f989 Reviewed-on: https://chromium-review.googlesource.com/1000140 Reviewed-by: Joshua Peraza <jperaza@chromium.org> Commit-Queue: Scott Graham <scottmg@chromium.org>
105 lines
3.7 KiB
C++
105 lines
3.7 KiB
C++
// Copyright 2014 The Crashpad Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "util/misc/capture_context.h"
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#include <stdint.h>
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#include <algorithm>
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#include "gtest/gtest.h"
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#include "util/misc/address_sanitizer.h"
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#include "util/misc/capture_context_test_util.h"
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namespace crashpad {
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namespace test {
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namespace {
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#if defined(OS_FUCHSIA)
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// Fuchsia uses -fsanitize=safe-stack by default, which splits local variables
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// and the call stack into separate regions (see
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// https://clang.llvm.org/docs/SafeStack.html). Because this test would like to
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// find an approximately valid stack pointer by comparing locals to the
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// captured one, disable safe-stack for this function.
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__attribute__((no_sanitize("safe-stack")))
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#endif
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void TestCaptureContext() {
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NativeCPUContext context_1;
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CaptureContext(&context_1);
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{
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SCOPED_TRACE("context_1");
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ASSERT_NO_FATAL_FAILURE(SanityCheckContext(context_1));
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}
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// The program counter reference value is this function’s address. The
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// captured program counter should be slightly greater than or equal to the
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// reference program counter.
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uintptr_t pc = ProgramCounterFromContext(context_1);
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#if !defined(ADDRESS_SANITIZER)
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// AddressSanitizer can cause enough code bloat that the “nearby” check would
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// likely fail.
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const uintptr_t kReferencePC =
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reinterpret_cast<uintptr_t>(TestCaptureContext);
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EXPECT_PRED2([](uintptr_t actual,
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uintptr_t reference) { return actual - reference < 64u; },
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pc,
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kReferencePC);
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#endif // !defined(ADDRESS_SANITIZER)
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// Declare sp and context_2 here because all local variables need to be
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// declared before computing the stack pointer reference value, so that the
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// reference value can be the lowest value possible.
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uintptr_t sp;
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NativeCPUContext context_2;
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// The stack pointer reference value is the lowest address of a local variable
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// in this function. The captured program counter will be slightly less than
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// or equal to the reference stack pointer.
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const uintptr_t kReferenceSP =
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std::min(std::min(reinterpret_cast<uintptr_t>(&context_1),
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reinterpret_cast<uintptr_t>(&context_2)),
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std::min(reinterpret_cast<uintptr_t>(&pc),
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reinterpret_cast<uintptr_t>(&sp)));
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sp = StackPointerFromContext(context_1);
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EXPECT_PRED2([](uintptr_t actual,
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uintptr_t reference) { return reference - actual < 512u; },
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sp,
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kReferenceSP);
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// Capture the context again, expecting that the stack pointer stays the same
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// and the program counter increases. Strictly speaking, there’s no guarantee
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// that these conditions will hold, although they do for known compilers even
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// under typical optimization.
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CaptureContext(&context_2);
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{
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SCOPED_TRACE("context_2");
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ASSERT_NO_FATAL_FAILURE(SanityCheckContext(context_2));
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}
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EXPECT_EQ(StackPointerFromContext(context_2), sp);
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EXPECT_GT(ProgramCounterFromContext(context_2), pc);
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}
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TEST(CaptureContext, CaptureContext) {
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ASSERT_NO_FATAL_FAILURE(TestCaptureContext());
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}
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} // namespace
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} // namespace test
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} // namespace crashpad
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