win: Add and use a custom CaptureContext() implementation

client/capture_context_mac_test.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 14 matching lines @@
 
 namespace crashpad {
 namespace test {
 namespace {
 
 // If the context structure has fields that tell whether it’s valid, such as
 // magic numbers or size fields, sanity-checks those fields for validity with
 // fatal gtest assertions. For other fields, where it’s possible to reason about
 // their validity based solely on their contents, sanity-checks via nonfatal
 // gtest assertions.
-void SanityCheckContext(NativeCPUContext* context) {
+void SanityCheckContext(const NativeCPUContext& context) {
 #if defined(ARCH_CPU_X86)
-  ASSERT_EQ(x86_THREAD_STATE32, context->tsh.flavor);
-  ASSERT_EQ(implicit_cast<int>(x86_THREAD_STATE32_COUNT), context->tsh.count);
+  ASSERT_EQ(x86_THREAD_STATE32, context.tsh.flavor);
+  ASSERT_EQ(implicit_cast<int>(x86_THREAD_STATE32_COUNT), context.tsh.count);
 #elif defined(ARCH_CPU_X86_64)
-  ASSERT_EQ(x86_THREAD_STATE64, context->tsh.flavor);
-  ASSERT_EQ(implicit_cast<int>(x86_THREAD_STATE64_COUNT), context->tsh.count);
+  ASSERT_EQ(x86_THREAD_STATE64, context.tsh.flavor);
+  ASSERT_EQ(implicit_cast<int>(x86_THREAD_STATE64_COUNT), context.tsh.count);
 #endif
 
 #if defined(ARCH_CPU_X86_FAMILY)
   // The segment registers are only capable of storing 16-bit quantities, but
   // the context structure provides native integer-width fields for them. Ensure
   // that the high bits are all clear.
   //
   // Many bit positions in the flags register are reserved and will always read
-  // a known value. Most reservd bits are always 0, but bit 1 is always 1. Check
-  // that the reserved bits are all set to their expected values. Note that the
-  // set of reserved bits may be relaxed over time with newer CPUs, and that
-  // this test may need to be changed to reflect these developments. The current
-  // set of reserved bits are 1, 3, 5, 15, and 22 and higher. See Intel Software
-  // Developer’s Manual, Volume 1: Basic Architecture (253665-051), 3.4.3
-  // “EFLAGS Register”, and AMD Architecture Programmer’s Manual, Volume 2:
-  // System Programming (24593-3.24), 3.1.6 “RFLAGS Register”.
+  // a known value. Most reserved bits are always 0, but bit 1 is always 1.
+  // Check that the reserved bits are all set to their expected values. Note
+  // that the set of reserved bits may be relaxed over time with newer CPUs, and
+  // that this test may need to be changed to reflect these developments. The
+  // current set of reserved bits are 1, 3, 5, 15, and 22 and higher. See Intel
+  // Software Developer’s Manual, Volume 1: Basic Architecture (253665-051),
+  // 3.4.3 “EFLAGS Register”, and AMD Architecture Programmer’s Manual, Volume
+  // 2: System Programming (24593-3.24), 3.1.6 “RFLAGS Register”.
 #if defined(ARCH_CPU_X86)
-  EXPECT_EQ(0u, context->uts.ts32.__cs & ~0xffff);
-  EXPECT_EQ(0u, context->uts.ts32.__ds & ~0xffff);
-  EXPECT_EQ(0u, context->uts.ts32.__es & ~0xffff);
-  EXPECT_EQ(0u, context->uts.ts32.__fs & ~0xffff);
-  EXPECT_EQ(0u, context->uts.ts32.__gs & ~0xffff);
-  EXPECT_EQ(0u, context->uts.ts32.__ss & ~0xffff);
-  EXPECT_EQ(2u, context->uts.ts32.__eflags & 0xffc0802a);
+  EXPECT_EQ(0u, context.uts.ts32.__cs & ~0xffff);
+  EXPECT_EQ(0u, context.uts.ts32.__ds & ~0xffff);
+  EXPECT_EQ(0u, context.uts.ts32.__es & ~0xffff);
+  EXPECT_EQ(0u, context.uts.ts32.__fs & ~0xffff);
+  EXPECT_EQ(0u, context.uts.ts32.__gs & ~0xffff);
+  EXPECT_EQ(0u, context.uts.ts32.__ss & ~0xffff);
+  EXPECT_EQ(2u, context.uts.ts32.__eflags & 0xffc0802a);
 #elif defined(ARCH_CPU_X86_64)
-  EXPECT_EQ(0u, context->uts.ts64.__cs & ~UINT64_C(0xffff));
-  EXPECT_EQ(0u, context->uts.ts64.__fs & ~UINT64_C(0xffff));
-  EXPECT_EQ(0u, context->uts.ts64.__gs & ~UINT64_C(0xffff));
-  EXPECT_EQ(2u, context->uts.ts64.__rflags & UINT64_C(0xffffffffffc0802a));
+  EXPECT_EQ(0u, context.uts.ts64.__cs & ~UINT64_C(0xffff));
+  EXPECT_EQ(0u, context.uts.ts64.__fs & ~UINT64_C(0xffff));
+  EXPECT_EQ(0u, context.uts.ts64.__gs & ~UINT64_C(0xffff));
+  EXPECT_EQ(2u, context.uts.ts64.__rflags & UINT64_C(0xffffffffffc0802a));
 #endif
 #endif
 }
 
 // A CPU-independent function to return the program counter.
-uintptr_t ProgramCounterFromContext(NativeCPUContext* context) {
+uintptr_t ProgramCounterFromContext(const NativeCPUContext& context) {
 #if defined(ARCH_CPU_X86)
-  return context->uts.ts32.__eip;
+  return context.uts.ts32.__eip;
 #elif defined(ARCH_CPU_X86_64)
-  return context->uts.ts64.__rip;
+  return context.uts.ts64.__rip;
 #endif
 }
 
 // A CPU-independent function to return the stack pointer.
-uintptr_t StackPointerFromContext(NativeCPUContext* context) {
+uintptr_t StackPointerFromContext(const NativeCPUContext& context) {
 #if defined(ARCH_CPU_X86)
-  return context->uts.ts32.__esp;
+  return context.uts.ts32.__esp;
 #elif defined(ARCH_CPU_X86_64)
-  return context->uts.ts64.__rsp;
+  return context.uts.ts64.__rsp;
 #endif
 }
 
 void TestCaptureContext() {
   NativeCPUContext context_1;
   CaptureContext(&context_1);
 
   {
     SCOPED_TRACE("context_1");
-    ASSERT_NO_FATAL_FAILURE(SanityCheckContext(&context_1));
+    ASSERT_NO_FATAL_FAILURE(SanityCheckContext(context_1));
   }
 
   // The program counter reference value is this function’s address. The
   // captured program counter should be slightly greater than or equal to the
   // reference program counter.
-  uintptr_t pc = ProgramCounterFromContext(&context_1);
+  uintptr_t pc = ProgramCounterFromContext(context_1);
 #if !__has_feature(address_sanitizer)
   // AddressSanitizer can cause enough code bloat that the “nearby” check would
   // likely fail.
   const uintptr_t kReferencePC =
       reinterpret_cast<uintptr_t>(TestCaptureContext);
   EXPECT_LT(pc - kReferencePC, 64u);
 #endif
 
   // Declare sp and context_2 here because all local variables need to be
   // declared before computing the stack pointer reference value, so that the
   // reference value can be the lowest value possible.
   uintptr_t sp;
   NativeCPUContext context_2;
 
   // The stack pointer reference value is the lowest address of a local variable
   // in this function. The captured program counter will be slightly less than
   // or equal to the reference stack pointer.
   const uintptr_t kReferenceSP =
       std::min(std::min(reinterpret_cast<uintptr_t>(&context_1),
                         reinterpret_cast<uintptr_t>(&context_2)),
                std::min(reinterpret_cast<uintptr_t>(&pc),
                         reinterpret_cast<uintptr_t>(&sp)));
-  sp = StackPointerFromContext(&context_1);
+  sp = StackPointerFromContext(context_1);
   EXPECT_LT(kReferenceSP - sp, 512u);
 
   // Capture the context again, expecting that the stack pointer stays the same
   // and the program counter increases. Strictly speaking, there’s no guarantee
   // that these conditions will hold, although they do for known compilers even
   // under typical optimization.
   CaptureContext(&context_2);
 
   {
     SCOPED_TRACE("context_2");
-    ASSERT_NO_FATAL_FAILURE(SanityCheckContext(&context_2));
+    ASSERT_NO_FATAL_FAILURE(SanityCheckContext(context_2));
   }
 
-  EXPECT_EQ(sp, StackPointerFromContext(&context_2));
-  EXPECT_GT(ProgramCounterFromContext(&context_2), pc);
+  EXPECT_EQ(sp, StackPointerFromContext(context_2));
+  EXPECT_GT(ProgramCounterFromContext(context_2), pc);
 }
 
 TEST(CaptureContextMac, CaptureContext) {
   ASSERT_NO_FATAL_FAILURE(TestCaptureContext());
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad