[Mesa-dev] [PATCH 1/2] gallivm: use sstream for dissasembling

[Oded Gabbay]

Currently, disassemble() directly prints to stdout. This has broke the
profiling support for llvmpipe JIT code.

This patch redirects the output to an sstream object, which is then
either gets printed to stdout (for assembly debugging) or gets written
to a file in /tmp/ (for profiling support).

Signed-off-by: Oded Gabbay <oded.gabbay at gmail.com>
---
 src/gallium/auxiliary/gallivm/lp_bld_debug.cpp | 51 +++++++++++++++-----------
 1 file changed, 30 insertions(+), 21 deletions(-)

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_debug.cpp b/src/gallium/auxiliary/gallivm/lp_bld_debug.cpp
index 7283e2f..7e98f1a 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_debug.cpp
+++ b/src/gallium/auxiliary/gallivm/lp_bld_debug.cpp
@@ -26,6 +26,9 @@
  **************************************************************************/
 
 #include <stddef.h>
+#include <fstream>
+#include <sstream>
+#include <iomanip>
 
 #include <llvm-c/Core.h>
 #include <llvm-c/Disassembler.h>
@@ -125,7 +128,7 @@ lp_debug_dump_value(LLVMValueRef value)
  * - http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html
  */
 static size_t
-disassemble(const void* func)
+disassemble(const void* func, std::stringstream &buffer)
 {
    const uint8_t *bytes = (const uint8_t *)func;
 
@@ -143,8 +146,8 @@ disassemble(const void* func)
    char outline[1024];
 
    if (!D) {
-      _debug_printf("error: couldn't create disassembler for triple %s\n",
-                    Triple.c_str());
+      buffer << "error: could not create disassembler for triple "
+             << Triple.c_str() << '\n';
       return 0;
    }
 
@@ -158,13 +161,13 @@ disassemble(const void* func)
        * so that between runs.
        */
 
-      _debug_printf("%6lu:\t", (unsigned long)pc);
+      buffer << std::setw(6) << (unsigned long)pc << ":\t";
 
       Size = LLVMDisasmInstruction(D, (uint8_t *)bytes + pc, extent - pc, 0, outline,
                                    sizeof outline);
 
       if (!Size) {
-         _debug_printf("invalid\n");
+         buffer << "invalid\n";
          pc += 1;
          break;
       }
@@ -176,10 +179,11 @@ disassemble(const void* func)
       if (0) {
          unsigned i;
          for (i = 0; i < Size; ++i) {
-            _debug_printf("%02x ", bytes[pc + i]);
+            buffer << std::hex << std::setfill('0') << std::setw(2)
+                   << static_cast<int> (bytes[pc + i]);
          }
          for (; i < 16; ++i) {
-            _debug_printf("   ");
+            buffer << std::dec << "   ";
          }
       }
 
@@ -187,9 +191,7 @@ disassemble(const void* func)
        * Print the instruction.
        */
 
-      _debug_printf("%*s", Size, outline);
-
-      _debug_printf("\n");
+      buffer << std::setw(Size) << outline << '\n';
 
       /*
        * Stop disassembling on return statements, if there is no record of a
@@ -209,12 +211,12 @@ disassemble(const void* func)
       pc += Size;
 
       if (pc >= extent) {
-         _debug_printf("disassembly larger than %ull bytes, aborting\n", extent);
+         buffer << "disassembly larger than " << extent << " bytes, aborting\n";
          break;
       }
    }
 
-   _debug_printf("\n");
+   buffer << '\n';
 
    LLVMDisasmDispose(D);
 
@@ -222,7 +224,8 @@ disassemble(const void* func)
     * Print GDB command, useful to verify output.
     */
    if (0) {
-      _debug_printf("disassemble %p %p\n", bytes, bytes + pc);
+      buffer << "disassemble " << static_cast<const void*>(bytes) << ' '
+             << static_cast<const void*>(bytes + pc) << '\n';
    }
 
    return pc;
@@ -231,8 +234,14 @@ disassemble(const void* func)
 
 extern "C" void
 lp_disassemble(LLVMValueRef func, const void *code) {
-   _debug_printf("%s:\n", LLVMGetValueName(func));
-   disassemble(code);
+   std::stringstream buffer;
+   std::string s;
+
+   buffer << LLVMGetValueName(func) << ":\n";
+   disassemble(code, buffer);
+   s = buffer.str();
+   _debug_printf("%s", s.c_str());
+   _debug_printf("\n");
 }
 
 
@@ -248,9 +257,10 @@ extern "C" void
 lp_profile(LLVMValueRef func, const void *code)
 {
 #if defined(__linux__) && defined(PROFILE)
+   std::stringstream buffer;
+   static std::ofstream perf_asm_file;
    static boolean first_time = TRUE;
    static FILE *perf_map_file = NULL;
-   static int perf_asm_fd = -1;
    if (first_time) {
       /*
        * We rely on the disassembler for determining a function's size, but
@@ -264,17 +274,16 @@ lp_profile(LLVMValueRef func, const void *code)
          util_snprintf(filename, sizeof filename, "/tmp/perf-%llu.map", (unsigned long long)pid);
          perf_map_file = fopen(filename, "wt");
          util_snprintf(filename, sizeof filename, "/tmp/perf-%llu.map.asm", (unsigned long long)pid);
-         mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
-         perf_asm_fd = open(filename, O_WRONLY | O_CREAT, mode);
+         perf_asm_file.open(filename);
       }
       first_time = FALSE;
    }
    if (perf_map_file) {
       const char *symbol = LLVMGetValueName(func);
       unsigned long addr = (uintptr_t)code;
-      llvm::raw_fd_ostream Out(perf_asm_fd, false);
-      Out << symbol << ":\n";
-      unsigned long size = disassemble(code);
+      buffer << symbol << ":\n";
+      unsigned long size = disassemble(code, buffer);
+      perf_asm_file << buffer.rdbuf() << std::flush;
       fprintf(perf_map_file, "%lx %lx %s\n", addr, size, symbol);
       fflush(perf_map_file);
    }
-- 
2.5.0