win x86: Grab bag of restructuring to get tests working on x86-on-x86

snapshot/win/cpu_context_win.cc

 // Copyright 2015 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
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 // Unless required by applicable law or agreed to in writing, software
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@@ skipping 10 matching lines @@
 
 namespace crashpad {
 
 #if defined(ARCH_CPU_64_BITS)
 
 void InitializeX86Context(const WOW64_CONTEXT& context, CPUContextX86* out) {
   CHECK(false) << "TODO(scottmg) InitializeX86Context()";
 }
 
 void InitializeX64Context(const CONTEXT& context, CPUContextX86_64* out) {
-  out->rax = context.Rax;
-  out->rbx = context.Rbx;
-  out->rcx = context.Rcx;
-  out->rdx = context.Rdx;
-  out->rdi = context.Rdi;
-  out->rsi = context.Rsi;
-  out->rbp = context.Rbp;
-  out->rsp = context.Rsp;
-  out->r8 = context.R8;
-  out->r9 = context.R9;
-  out->r10 = context.R10;
-  out->r11 = context.R11;
-  out->r12 = context.R12;
-  out->r13 = context.R13;
-  out->r14 = context.R14;
-  out->r15 = context.R15;
-  out->rip = context.Rip;
-  out->rflags = context.EFlags;
-  out->cs = context.SegCs;
-  out->fs = context.SegFs;
-  out->gs = context.SegGs;
+  memset(out, 0, sizeof(*out));
 

[Mark Mentovai, 2015/09/16 18:56:58]

Maybe also LOG_IF(…, !(context.ContextFlags & CONTEXT_AMD64)), and similar in
the x86 function below.

[scottmg, 2015/09/16 19:38:21]

Done.

(I was confused at first why these don't trigger in the test, but
CONTEXT_INTEGER, etc. all have it or'd in. So it won't work for WOW64 once I get
there.)

-  out->dr0 = context.Dr0;
-  out->dr1 = context.Dr1;
-  out->dr2 = context.Dr2;
-  out->dr3 = context.Dr3;
-  // DR4 and DR5 are obsolete synonyms for DR6 and DR7, see
-  // http://en.wikipedia.org/wiki/X86_debug_register.
-  out->dr4 = context.Dr6;
-  out->dr5 = context.Dr7;
-  out->dr6 = context.Dr6;
-  out->dr7 = context.Dr7;
+  if (context.ContextFlags & CONTEXT_CONTROL) {
+    out->cs = context.SegCs;
+    out->rflags = context.EFlags;
+    out->rip = context.Rip;
+    out->rsp = context.Rsp;
+    // SegSs ignored.
+  }
 
-  static_assert(sizeof(out->fxsave) == sizeof(context.FltSave),
-                "types must be equivalent");
-  memcpy(&out->fxsave, &context.FltSave.ControlWord, sizeof(out->fxsave));
+  if (context.ContextFlags & CONTEXT_INTEGER) {
+    out->rax = context.Rax;
+    out->rbx = context.Rbx;
+    out->rcx = context.Rcx;
+    out->rdx = context.Rdx;
+    out->rdi = context.Rdi;
+    out->rsi = context.Rsi;
+    out->rbp = context.Rbp;
+    out->r8 = context.R8;
+    out->r9 = context.R9;
+    out->r10 = context.R10;
+    out->r11 = context.R11;
+    out->r12 = context.R12;
+    out->r13 = context.R13;
+    out->r14 = context.R14;
+    out->r15 = context.R15;
+  }
+
+  if (context.ContextFlags & CONTEXT_SEGMENTS) {
+    out->fs = context.SegFs;
+    out->gs = context.SegGs;
+    // SegDs ignored.
+    // SegEs ignored.
+  }
+
+  if (context.ContextFlags & CONTEXT_DEBUG_REGISTERS) {
+    out->dr0 = context.Dr0;
+    out->dr1 = context.Dr1;
+    out->dr2 = context.Dr2;
+    out->dr3 = context.Dr3;
+    // DR4 and DR5 are obsolete synonyms for DR6 and DR7, see
+    // https://en.wikipedia.org/wiki/X86_debug_register.
+    out->dr4 = context.Dr6;
+    out->dr5 = context.Dr7;
+    out->dr6 = context.Dr6;
+    out->dr7 = context.Dr7;
+  }
+
+  if (context.ContextFlags & CONTEXT_FLOATING_POINT) {
+    static_assert(sizeof(out->fxsave) == sizeof(context.FltSave),
+                  "types must be equivalent");
+    memcpy(&out->fxsave, &context.FltSave.ControlWord, sizeof(out->fxsave));
+  }
 }
 
 #else  // ARCH_CPU_64_BITS
 
 void InitializeX86Context(const CONTEXT& context, CPUContextX86* out) {
-  CHECK(false) << "TODO(scottmg) InitializeX86Context()";
+  memset(out, 0, sizeof(*out));
+
+  if (context.ContextFlags & CONTEXT_CONTROL) {
+    out->ebp = context.Ebp;
+    out->eip = context.Eip;
+    out->cs = static_cast<uint16_t>(context.SegCs);
+    out->eflags = context.EFlags;
+    out->esp = context.Esp;
+    out->ss = static_cast<uint16_t>(context.SegSs);
+  }
+
+  if (context.ContextFlags & CONTEXT_INTEGER) {
+    out->eax = context.Eax;
+    out->ebx = context.Ebx;
+    out->ecx = context.Ecx;
+    out->edx = context.Edx;
+    out->edi = context.Edi;
+    out->esi = context.Esi;
+  }
+
+  if (context.ContextFlags & CONTEXT_SEGMENTS) {
+    out->ds = static_cast<uint16_t>(context.SegDs);
+    out->es = static_cast<uint16_t>(context.SegEs);
+    out->fs = static_cast<uint16_t>(context.SegFs);
+    out->gs = static_cast<uint16_t>(context.SegGs);
+  }
+
+  if (context.ContextFlags & CONTEXT_DEBUG_REGISTERS) {
+    out->dr0 = context.Dr0;
+    out->dr1 = context.Dr1;
+    out->dr2 = context.Dr2;
+    out->dr3 = context.Dr3;
+    // DR4 and DR5 are obsolete synonyms for DR6 and DR7, see
+    // https://en.wikipedia.org/wiki/X86_debug_register.
+    out->dr4 = context.Dr6;
+    out->dr5 = context.Dr7;
+    out->dr6 = context.Dr6;
+    out->dr7 = context.Dr7;
+  }
+
+  if (context.ContextFlags & CONTEXT_EXTENDED_REGISTERS) {
+    static_assert(sizeof(out->fxsave) == sizeof(context.ExtendedRegisters),
+                  "types must be equivalent");
+    memcpy(&out->fxsave, &context.ExtendedRegisters, sizeof(out->fxsave));
+  } else if (context.ContextFlags & CONTEXT_FLOATING_POINT) {
+    CHECK(false) << "TODO(scottmg): extract x87 data";
+  }
 }
 
 #endif  // ARCH_CPU_64_BITS
 
 }  // namespace crashpad