1/**************************************************************************
2 *
3 * Copyright 2009-2011 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28#include <stddef.h>
29#include <fstream>
30#include <sstream>
31#include <iomanip>
32
33#include <llvm/Config/llvm-config.h>
34#include <llvm-c/Core.h>
35#include <llvm-c/Disassembler.h>
36#include <llvm/Support/raw_ostream.h>
37#include <llvm/Support/Format.h>
38#include <llvm/Support/Host.h>
39#include <llvm/IR/Module.h>
40
41#include "util/u_math.h"
42#include "util/u_debug.h"
43
44#include "lp_bld_debug.h"
45
46#ifdef __linux__
47#include <sys/stat.h>
48#include <fcntl.h>
49#endif
50
51
52
53/**
54 * Check alignment.
55 *
56 * It is important that this check is not implemented as a macro or inlined
57 * function, as the compiler assumptions in respect to alignment of global
58 * and stack variables would often make the check a no op, defeating the
59 * whole purpose of the exercise.
60 */
61extern "C" boolean
62lp_check_alignment(const void *ptr, unsigned alignment)
63{
64   assert(util_is_power_of_two_or_zero(alignment));
65   return ((uintptr_t)ptr & (alignment - 1)) == 0;
66}
67
68
69/**
70 * Same as LLVMDumpValue, but through our debugging channels.
71 */
72extern "C" void
73lp_debug_dump_value(LLVMValueRef value)
74{
75   char *str = LLVMPrintValueToString(value);
76   if (str) {
77      os_log_message(str);
78      LLVMDisposeMessage(str);
79   }
80}
81
82
83/*
84 * Disassemble a function, using the LLVM MC disassembler.
85 *
86 * See also:
87 * - http://blog.llvm.org/2010/01/x86-disassembler.html
88 * - http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html
89 */
90static size_t
91disassemble(const void* func, std::ostream &buffer)
92{
93   const uint8_t *bytes = (const uint8_t *)func;
94
95   /*
96    * Limit disassembly to this extent
97    */
98   const uint64_t extent = 96 * 1024;
99
100   /*
101    * Initialize all used objects.
102    */
103
104   const char *triple = LLVM_HOST_TRIPLE;
105   LLVMDisasmContextRef D = LLVMCreateDisasm(triple, NULL, 0, NULL, NULL);
106   char outline[1024];
107
108   if (!D) {
109      buffer << "error: could not create disassembler for triple "
110             << triple << '\n';
111      return 0;
112   }
113
114   uint64_t pc;
115   pc = 0;
116   while (pc < extent) {
117      size_t Size;
118
119      /*
120       * Print address.  We use addresses relative to the start of the function,
121       * so that between runs.
122       */
123
124      buffer << std::setw(6) << (unsigned long)pc << ":\t";
125
126      Size = LLVMDisasmInstruction(D, (uint8_t *)bytes + pc, extent - pc, 0, outline,
127                                   sizeof outline);
128
129      if (!Size) {
130         buffer << "invalid\n";
131         pc += 1;
132         break;
133      }
134
135      /*
136       * Output the bytes in hexidecimal format.
137       */
138
139      if (0) {
140         unsigned i;
141         for (i = 0; i < Size; ++i) {
142            buffer << std::hex << std::setfill('0') << std::setw(2)
143                   << static_cast<int> (bytes[pc + i]);
144         }
145         for (; i < 16; ++i) {
146            buffer << std::dec << "   ";
147         }
148      }
149
150      /*
151       * Print the instruction.
152       */
153
154      buffer << std::setw(Size) << outline << '\n';
155
156      /*
157       * Stop disassembling on return statements, if there is no record of a
158       * jump to a successive address.
159       *
160       * XXX: This currently assumes x86
161       */
162
163#if defined(PIPE_ARCH_X86) || defined(PIPE_ARCH_X86_64)
164      if (Size == 1 && bytes[pc] == 0xc3) {
165         break;
166      }
167#endif
168
169      /*
170       * Advance.
171       */
172
173      pc += Size;
174
175      if (pc >= extent) {
176         buffer << "disassembly larger than " << extent << " bytes, aborting\n";
177         break;
178      }
179   }
180
181   buffer << '\n';
182
183   LLVMDisasmDispose(D);
184
185   /*
186    * Print GDB command, useful to verify output.
187    */
188   if (0) {
189      buffer << "disassemble " << static_cast<const void*>(bytes) << ' '
190             << static_cast<const void*>(bytes + pc) << '\n';
191   }
192
193   return pc;
194}
195
196
197extern "C" void
198lp_disassemble(LLVMValueRef func, const void *code)
199{
200   std::ostringstream buffer;
201   std::string s;
202
203   buffer << LLVMGetValueName(func) << ":\n";
204   disassemble(code, buffer);
205   s = buffer.str();
206   os_log_message(s.c_str());
207   os_log_message("\n");
208}
209
210
211/*
212 * Linux perf profiler integration.
213 *
214 * See also:
215 * - http://penberg.blogspot.co.uk/2009/06/jato-has-profiler.html
216 * - https://github.com/penberg/jato/commit/73ad86847329d99d51b386f5aba692580d1f8fdc
217 * - http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=80d496be89ed7dede5abee5c057634e80a31c82d
218 */
219extern "C" void
220lp_profile(LLVMValueRef func, const void *code)
221{
222#if defined(__linux__) && defined(PROFILE)
223   static std::ofstream perf_asm_file;
224   static boolean first_time = TRUE;
225   static FILE *perf_map_file = NULL;
226   if (first_time) {
227      /*
228       * We rely on the disassembler for determining a function's size, but
229       * the disassembly is a leaky and slow operation, so avoid running
230       * this except when running inside linux perf, which can be inferred
231       * by the PERF_BUILDID_DIR environment variable.
232       */
233      if (getenv("PERF_BUILDID_DIR")) {
234         pid_t pid = getpid();
235         char filename[256];
236         snprintf(filename, sizeof filename, "/tmp/perf-%llu.map", (unsigned long long)pid);
237         perf_map_file = fopen(filename, "wt");
238         snprintf(filename, sizeof filename, "/tmp/perf-%llu.map.asm", (unsigned long long)pid);
239         perf_asm_file.open(filename);
240      }
241      first_time = FALSE;
242   }
243   if (perf_map_file) {
244      const char *symbol = LLVMGetValueName(func);
245      unsigned long addr = (uintptr_t)code;
246      perf_asm_file << symbol << ":\n";
247      unsigned long size = disassemble(code, perf_asm_file);
248      perf_asm_file.flush();
249      fprintf(perf_map_file, "%lx %lx %s\n", addr, size, symbol);
250      fflush(perf_map_file);
251   }
252#else
253   (void)func;
254   (void)code;
255#endif
256}
257
258
259