clang  10.0.0svn
Stack.h
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1 //===--- Stack.h - Utilities for dealing with stack space -------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// Defines utilities for dealing with stack allocation and stack space.
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_BASIC_STACK_H
15 #define LLVM_CLANG_BASIC_STACK_H
16 
17 #include <cstddef>
18 
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/Support/Compiler.h"
21 
22 namespace clang {
23  /// The amount of stack space that Clang would like to be provided with.
24  /// If less than this much is available, we may be unable to reach our
25  /// template instantiation depth limit and other similar limits.
26  constexpr size_t DesiredStackSize = 8 << 20;
27 
28  /// Call this once on each thread, as soon after starting the thread as
29  /// feasible, to note the approximate address of the bottom of the stack.
30  void noteBottomOfStack();
31 
32  /// Determine whether the stack is nearly exhausted.
34 
35  void runWithSufficientStackSpaceSlow(llvm::function_ref<void()> Diag,
36  llvm::function_ref<void()> Fn);
37 
38  /// Run a given function on a stack with "sufficient" space. If stack space
39  /// is insufficient, calls Diag to emit a diagnostic before calling Fn.
40  inline void runWithSufficientStackSpace(llvm::function_ref<void()> Diag,
41  llvm::function_ref<void()> Fn) {
42 #ifdef LLVM_ENABLE_THREADS
43  if (LLVM_UNLIKELY(isStackNearlyExhausted()))
45  else
46  Fn();
47 #else
48  if (LLVM_UNLIKELY(isStackNearlyExhausted()))
49  Diag();
50  Fn();
51 #endif
52  }
53 } // end namespace clang
54 
55 #endif // LLVM_CLANG_BASIC_STACK_H
static DiagnosticBuilder Diag(DiagnosticsEngine *Diags, const LangOptions &Features, FullSourceLoc TokLoc, const char *TokBegin, const char *TokRangeBegin, const char *TokRangeEnd, unsigned DiagID)
Produce a diagnostic highlighting some portion of a literal.
bool isStackNearlyExhausted()
Determine whether the stack is nearly exhausted.
Definition: Stack.cpp:46
void runWithSufficientStackSpace(llvm::function_ref< void()> Diag, llvm::function_ref< void()> Fn)
Run a given function on a stack with "sufficient" space.
Definition: Stack.h:40
void noteBottomOfStack()
Call this once on each thread, as soon after starting the thread as feasible, to note the approximate...
Definition: Stack.cpp:41
constexpr size_t DesiredStackSize
The amount of stack space that Clang would like to be provided with.
Definition: Stack.h:26
Dataflow Directional Tag Classes.
void runWithSufficientStackSpaceSlow(llvm::function_ref< void()> Diag, llvm::function_ref< void()> Fn)
Definition: Stack.cpp:67