cc1_main.cpp revision 344779 
1//===-- cc1_main.cpp - Clang CC1 Compiler Frontend ------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This is the entry point to the clang -cc1 functionality, which implements the
11// core compiler functionality along with a number of additional tools for
12// demonstration and testing purposes.
13//
14//===----------------------------------------------------------------------===//
15
16#include "clang/Basic/Stack.h"
17#include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
18#include "clang/Config/config.h"
19#include "clang/Driver/DriverDiagnostic.h"
20#include "clang/Driver/Options.h"
21#include "clang/Frontend/CompilerInstance.h"
22#include "clang/Frontend/CompilerInvocation.h"
23#include "clang/Frontend/FrontendDiagnostic.h"
24#include "clang/Frontend/TextDiagnosticBuffer.h"
25#include "clang/Frontend/TextDiagnosticPrinter.h"
26#include "clang/Frontend/Utils.h"
27#include "clang/FrontendTool/Utils.h"
28#include "llvm/ADT/Statistic.h"
29#include "llvm/Config/llvm-config.h"
30#include "llvm/LinkAllPasses.h"
31#include "llvm/Option/Arg.h"
32#include "llvm/Option/ArgList.h"
33#include "llvm/Option/OptTable.h"
34#include "llvm/Support/BuryPointer.h"
35#include "llvm/Support/Compiler.h"
36#include "llvm/Support/ErrorHandling.h"
37#include "llvm/Support/ManagedStatic.h"
38#include "llvm/Support/Signals.h"
39#include "llvm/Support/TargetSelect.h"
40#include "llvm/Support/Timer.h"
41#include "llvm/Support/raw_ostream.h"
42#include <cstdio>
43
44#ifdef CLANG_HAVE_RLIMITS
45#include <sys/resource.h>
46#endif
47
48using namespace clang;
49using namespace llvm::opt;
50
51//===----------------------------------------------------------------------===//
52// Main driver
53//===----------------------------------------------------------------------===//
54
55static void LLVMErrorHandler(void *UserData, const std::string &Message,
56                             bool GenCrashDiag) {
57  DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
58
59  Diags.Report(diag::err_fe_error_backend) << Message;
60
61  // Run the interrupt handlers to make sure any special cleanups get done, in
62  // particular that we remove files registered with RemoveFileOnSignal.
63  llvm::sys::RunInterruptHandlers();
64
65  // We cannot recover from llvm errors.  When reporting a fatal error, exit
66  // with status 70 to generate crash diagnostics.  For BSD systems this is
67  // defined as an internal software error.  Otherwise, exit with status 1.
68  exit(GenCrashDiag ? 70 : 1);
69}
70
71#ifdef LINK_POLLY_INTO_TOOLS
72namespace polly {
73void initializePollyPasses(llvm::PassRegistry &Registry);
74}
75#endif
76
77#ifdef CLANG_HAVE_RLIMITS
78#if defined(__linux__) && defined(__PIE__)
79static size_t getCurrentStackAllocation() {
80  // If we can't compute the current stack usage, allow for 512K of command
81  // line arguments and environment.
82  size_t Usage = 512 * 1024;
83  if (FILE *StatFile = fopen("/proc/self/stat", "r")) {
84    // We assume that the stack extends from its current address to the end of
85    // the environment space. In reality, there is another string literal (the
86    // program name) after the environment, but this is close enough (we only
87    // need to be within 100K or so).
88    unsigned long StackPtr, EnvEnd;
89    // Disable silly GCC -Wformat warning that complains about length
90    // modifiers on ignored format specifiers. We want to retain these
91    // for documentation purposes even though they have no effect.
92#if defined(__GNUC__) && !defined(__clang__)
93#pragma GCC diagnostic push
94#pragma GCC diagnostic ignored "-Wformat"
95#endif
96    if (fscanf(StatFile,
97               "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*lu %*lu %*lu %*lu %*lu "
98               "%*lu %*ld %*ld %*ld %*ld %*ld %*ld %*llu %*lu %*ld %*lu %*lu "
99               "%*lu %*lu %lu %*lu %*lu %*lu %*lu %*lu %*llu %*lu %*lu %*d %*d "
100               "%*u %*u %*llu %*lu %*ld %*lu %*lu %*lu %*lu %*lu %*lu %lu %*d",
101               &StackPtr, &EnvEnd) == 2) {
102#if defined(__GNUC__) && !defined(__clang__)
103#pragma GCC diagnostic pop
104#endif
105      Usage = StackPtr < EnvEnd ? EnvEnd - StackPtr : StackPtr - EnvEnd;
106    }
107    fclose(StatFile);
108  }
109  return Usage;
110}
111
112#include <alloca.h>
113
114LLVM_ATTRIBUTE_NOINLINE
115static void ensureStackAddressSpace() {
116  // Linux kernels prior to 4.1 will sometimes locate the heap of a PIE binary
117  // relatively close to the stack (they are only guaranteed to be 128MiB
118  // apart). This results in crashes if we happen to heap-allocate more than
119  // 128MiB before we reach our stack high-water mark.
120  //
121  // To avoid these crashes, ensure that we have sufficient virtual memory
122  // pages allocated before we start running.
123  size_t Curr = getCurrentStackAllocation();
124  const int kTargetStack = DesiredStackSize - 256 * 1024;
125  if (Curr < kTargetStack) {
126    volatile char *volatile Alloc =
127        static_cast<volatile char *>(alloca(kTargetStack - Curr));
128    Alloc[0] = 0;
129    Alloc[kTargetStack - Curr - 1] = 0;
130  }
131}
132#else
133static void ensureStackAddressSpace() {}
134#endif
135
136/// Attempt to ensure that we have at least 8MiB of usable stack space.
137static void ensureSufficientStack() {
138  struct rlimit rlim;
139  if (getrlimit(RLIMIT_STACK, &rlim) != 0)
140    return;
141
142  // Increase the soft stack limit to our desired level, if necessary and
143  // possible.
144  if (rlim.rlim_cur != RLIM_INFINITY &&
145      rlim.rlim_cur < rlim_t(DesiredStackSize)) {
146    // Try to allocate sufficient stack.
147    if (rlim.rlim_max == RLIM_INFINITY ||
148        rlim.rlim_max >= rlim_t(DesiredStackSize))
149      rlim.rlim_cur = DesiredStackSize;
150    else if (rlim.rlim_cur == rlim.rlim_max)
151      return;
152    else
153      rlim.rlim_cur = rlim.rlim_max;
154
155    if (setrlimit(RLIMIT_STACK, &rlim) != 0 ||
156        rlim.rlim_cur != DesiredStackSize)
157      return;
158  }
159
160  // We should now have a stack of size at least DesiredStackSize. Ensure
161  // that we can actually use that much, if necessary.
162  ensureStackAddressSpace();
163}
164#else
165static void ensureSufficientStack() {}
166#endif
167
168int cc1_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
169  ensureSufficientStack();
170
171  std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());
172  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
173
174  // Register the support for object-file-wrapped Clang modules.
175  auto PCHOps = Clang->getPCHContainerOperations();
176  PCHOps->registerWriter(llvm::make_unique<ObjectFilePCHContainerWriter>());
177  PCHOps->registerReader(llvm::make_unique<ObjectFilePCHContainerReader>());
178
179  // Initialize targets first, so that --version shows registered targets.
180  llvm::InitializeAllTargets();
181  llvm::InitializeAllTargetMCs();
182  llvm::InitializeAllAsmPrinters();
183  llvm::InitializeAllAsmParsers();
184
185#ifdef LINK_POLLY_INTO_TOOLS
186  llvm::PassRegistry &Registry = *llvm::PassRegistry::getPassRegistry();
187  polly::initializePollyPasses(Registry);
188#endif
189
190  // Buffer diagnostics from argument parsing so that we can output them using a
191  // well formed diagnostic object.
192  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
193  TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer;
194  DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagsBuffer);
195  bool Success = CompilerInvocation::CreateFromArgs(
196      Clang->getInvocation(), Argv.begin(), Argv.end(), Diags);
197
198  // Infer the builtin include path if unspecified.
199  if (Clang->getHeaderSearchOpts().UseBuiltinIncludes &&
200      Clang->getHeaderSearchOpts().ResourceDir.empty())
201    Clang->getHeaderSearchOpts().ResourceDir =
202      CompilerInvocation::GetResourcesPath(Argv0, MainAddr);
203
204  // Create the actual diagnostics engine.
205  Clang->createDiagnostics();
206  if (!Clang->hasDiagnostics())
207    return 1;
208
209  // Set an error handler, so that any LLVM backend diagnostics go through our
210  // error handler.
211  llvm::install_fatal_error_handler(LLVMErrorHandler,
212                                  static_cast<void*>(&Clang->getDiagnostics()));
213
214  DiagsBuffer->FlushDiagnostics(Clang->getDiagnostics());
215  if (!Success)
216    return 1;
217
218  // Execute the frontend actions.
219  Success = ExecuteCompilerInvocation(Clang.get());
220
221  // If any timers were active but haven't been destroyed yet, print their
222  // results now.  This happens in -disable-free mode.
223  llvm::TimerGroup::printAll(llvm::errs());
224
225  // Our error handler depends on the Diagnostics object, which we're
226  // potentially about to delete. Uninstall the handler now so that any
227  // later errors use the default handling behavior instead.
228  llvm::remove_fatal_error_handler();
229
230  // When running with -disable-free, don't do any destruction or shutdown.
231  if (Clang->getFrontendOpts().DisableFree) {
232    llvm::BuryPointer(std::move(Clang));
233    return !Success;
234  }
235
236  return !Success;
237}
238