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cppgc: Conservative stack for ia32 Windows using clang

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Add support for ia32 Windows using clang. Change the callback
function from a member function to a free function. This the
compiler generating thiscall calling convention for the member
function which allows for keeping the asm trampoline uniform.

Bug: chromium:1056170
Change-Id: Ic8fcac27a628a0de026d8fe7d2e376c8f58a1737
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2134136
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66975}
This commit is contained in:
Michael Lippautz 2020-04-02 22:57:19 +02:00 committed by Commit Bot
parent aecd1e5811
commit 1e1323980f
4 changed files with 39 additions and 45 deletions
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16
BUILD.gn
View File

@ -348,12 +348,8 @@ config("libbase_config") {
# This config should be applied to code using the cppgc_base.
config("cppgc_base_config") {
if (target_cpu == "x64") {
if (is_clang) {
defines = [ "CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN" ]
}
} else if (target_cpu == "x86") {
if (is_clang && !is_win) {
if (is_clang) {
if (target_cpu == "x64" || target_cpu == "x86") {
defines = [ "CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN" ]
}
}
@ -3969,12 +3965,10 @@ v8_source_set("cppgc_base") {
"src/heap/cppgc/stack.h",
]
if (target_cpu == "x64") {
if (is_clang) {
if (is_clang) {
if (target_cpu == "x64") {
sources += [ "src/heap/cppgc/asm/x64/push_registers_clang.cc" ]
}
} else if (target_cpu == "x86") {
if (is_clang && !is_win) {
} else if (target_cpu == "x86") {
sources += [ "src/heap/cppgc/asm/ia32/push_registers_clang.cc" ]
}
}

17
src/heap/cppgc/asm/ia32/push_registers_clang.cc
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@ -7,14 +7,9 @@
//
// See asm/x64/push_registers_clang.cc for why the function is not generated
// using clang.
//
// Do not depend on V8_TARGET_OS_* defines as some embedders may override the
// GN toolchain (e.g. ChromeOS) and not provide them.
#ifdef _WIN32
#error "Not yet supported"
#else // !_WIN32
// We maintain 16-byte alignment at calls. There is an 4-byte return address
// on the stack and we push 28 bytes which maintains 16-byte stack alignment
@ -22,9 +17,15 @@
//
// The following assumes cdecl calling convention.
// Source: https://en.wikipedia.org/wiki/X86_calling_conventions#cdecl
asm(".globl PushAllRegistersAndIterateStack \n"
asm(
#ifdef _WIN32
".globl _PushAllRegistersAndIterateStack \n"
"_PushAllRegistersAndIterateStack: \n"
#else // !_WIN32
".globl PushAllRegistersAndIterateStack \n"
".hidden PushAllRegistersAndIterateStack \n"
"PushAllRegistersAndIterateStack: \n"
#endif // !_WIN32
// [ IterateStackCallback ]
// [ StackVisitor* ]
// [ Stack* ]
@ -49,5 +50,3 @@ asm(".globl PushAllRegistersAndIterateStack \n"
// Restore rbp as it was used as frame pointer.
" pop %ebp \n"
" ret \n");
#endif // !_WIN32

42
src/heap/cppgc/stack.cc
View File

@ -13,7 +13,7 @@
namespace cppgc {
namespace internal {
using IterateStackCallback = void (Stack::*)(StackVisitor*, intptr_t*) const;
using IterateStackCallback = void (*)(const Stack*, StackVisitor*, intptr_t*);
extern "C" void PushAllRegistersAndIterateStack(const Stack*, StackVisitor*,
IterateStackCallback);
@ -88,23 +88,14 @@ void IterateSafeStackIfNecessary(StackVisitor* visitor) {
#endif // defined(__has_feature)
}
#endif // CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
} // namespace
#ifdef CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
void Stack::IteratePointers(StackVisitor* visitor) const {
PushAllRegistersAndIterateStack(this, visitor, &Stack::IteratePointersImpl);
// No need to deal with callee-saved registers as they will be kept alive by
// the regular conservative stack iteration.
IterateSafeStackIfNecessary(visitor);
}
#endif // CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
// Called by the trampoline that pushes registers on the stack. This method
// should never be inlined to ensure that a possible redzone cannot contain
// any data that needs to be scanned.
V8_NOINLINE
// No ASAN support as method accesses redzones while walking the stack.
NO_SANITIZE_ADDRESS
void Stack::IteratePointersImpl(StackVisitor* visitor,
intptr_t* stack_end) const {
void IteratePointersImpl(const Stack* stack, StackVisitor* visitor,
intptr_t* stack_end) {
#ifdef V8_USE_ADDRESS_SANITIZER
void* asan_fake_stack = __asan_get_current_fake_stack();
#endif // V8_USE_ADDRESS_SANITIZER
@ -113,7 +104,7 @@ void Stack::IteratePointersImpl(StackVisitor* visitor,
constexpr size_t kMinStackAlignment = sizeof(void*);
void** current = reinterpret_cast<void**>(stack_end);
CHECK_EQ(0u, reinterpret_cast<uintptr_t>(current) & (kMinStackAlignment - 1));
for (; current < stack_start_; ++current) {
for (; current < stack->stack_start(); ++current) {
// MSAN: Instead of unpoisoning the whole stack, the slot's value is copied
// into a local which is unpoisoned.
void* address = *current;
@ -121,11 +112,24 @@ void Stack::IteratePointersImpl(StackVisitor* visitor,
if (address == nullptr) continue;
visitor->VisitPointer(address);
#ifdef V8_USE_ADDRESS_SANITIZER
IterateAsanFakeFrameIfNecessary(visitor, asan_fake_stack, stack_start_,
stack_end, address);
IterateAsanFakeFrameIfNecessary(visitor, asan_fake_stack,
stack->stack_start(), stack_end, address);
#endif // V8_USE_ADDRESS_SANITIZER
}
}
#endif // CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
} // namespace
#ifdef CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
void Stack::IteratePointers(StackVisitor* visitor) const {
PushAllRegistersAndIterateStack(this, visitor, &IteratePointersImpl);
// No need to deal with callee-saved registers as they will be kept alive by
// the regular conservative stack iteration.
IterateSafeStackIfNecessary(visitor);
}
#endif // CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
} // namespace internal
} // namespace cppgc

9
src/heap/cppgc/stack.h
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@ -32,13 +32,10 @@ class V8_EXPORT_PRIVATE Stack final {
void IteratePointers(StackVisitor* visitor) const;
#endif // CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
private:
// Called by the trampoline that pushes registers on the stack. This method
// should never be inlined to ensure that a possible redzone cannot contain
// any data that needs to be scanned.
V8_NOINLINE void IteratePointersImpl(StackVisitor* visitor,
intptr_t* stack_end) const;
// Returns the start of the stack.
const void* stack_start() const { return stack_start_; }
private:
const void* stack_start_;
};