Contribution of PowerPC port.

src/base/cpu.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/cpu.h"
 
 #if V8_LIBC_MSVCRT
 #include <intrin.h>  // __cpuid()
 #endif
 #if V8_OS_POSIX
 #include <unistd.h>  // sysconf()
 #endif
 #if V8_OS_QNX
 #include <sys/syspage.h>  // cpuinfo
 #endif
+#if V8_OS_LINUX && V8_HOST_ARCH_PPC
+#include <elf.h>
+#endif
 
 #include <ctype.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <algorithm>
 
 #include "src/base/logging.h"
 #if V8_OS_WIN
@@ skipping 215 matching lines @@
 
 CPU::CPU() : stepping_(0),
              model_(0),
              ext_model_(0),
              family_(0),
              ext_family_(0),
              type_(0),
              implementer_(0),
              architecture_(0),
              part_(0),
+             cache_line_size_(0),

[danno, 2014/07/29 13:24:08]

Seems like it makes sense to add a sentinel constant here, e.g.
UNKOWN_CACHE_LINE_SIZE = 0.

[andrew_low, 2014/07/30 13:27:05]

Seems sensible, I've made what I believe are the changes you're asking for. 

On 2014/07/29 13:24:08, danno wrote:

              has_fpu_(false),
              has_cmov_(false),
              has_sahf_(false),
              has_mmx_(false),
              has_sse_(false),
              has_sse2_(false),
              has_sse3_(false),
              has_ssse3_(false),
              has_sse41_(false),
              has_sse42_(false),
@@ skipping 225 matching lines @@
   char* part = cpu_info.ExtractField("CPU part");
   if (part != NULL) {
     char* end ;
     part_ = strtol(part, &end, 0);
     if (end == part) {
       part_ = 0;
     }
     delete[] part;
   }
 
+#elif V8_HOST_ARCH_PPC
+
+#if V8_OS_LINUX && !defined(USE_SIMULATOR)
+  // Read processor info from /proc/self/auxv.
+  char *auxv_cpu_type = NULL;
+  unsigned auxv_cache_line_size = 0;
+  FILE* fp = fopen("/proc/self/auxv", "r");
+  if (fp != NULL) {
+#if V8_TARGET_ARCH_PPC64
+    Elf64_auxv_t entry;
+#else
+    Elf32_auxv_t entry;
+#endif
+    for (;;) {
+      size_t n = fread(&entry, sizeof(entry), 1, fp);
+      if (n == 0 || entry.a_type == AT_NULL) {
+        break;
+      }
+      if (entry.a_type == AT_PLATFORM) {
+        auxv_cpu_type = reinterpret_cast<char*>(entry.a_un.a_val);
+        break;
+      } else if (entry.a_type == AT_DCACHEBSIZE ||
+                 entry.a_type == AT_ICACHEBSIZE ||
+                 entry.a_type == AT_UCACHEBSIZE) {
+        unsigned cachebsize = entry.a_un.a_val;
+        if (cachebsize > 0 &&
+            (auxv_cache_line_size == 0 || cachebsize < auxv_cache_line_size)) {
+          auxv_cache_line_size = cachebsize;
+        }
+      }
+    }
+    fclose(fp);
+  }
+
+  part_ = -1;
+  if (auxv_cpu_type) {
+    if (strcmp(auxv_cpu_type, "power8") == 0) {
+      part_ = PPC_POWER8;
+    } else if (strcmp(auxv_cpu_type, "power7") == 0) {
+      part_ = PPC_POWER7;
+    } else if (strcmp(auxv_cpu_type, "power6") == 0) {
+      part_ = PPC_POWER6;
+    } else if (strcmp(auxv_cpu_type, "power5") == 0) {
+      part_ = PPC_POWER5;
+    } else if (strcmp(auxv_cpu_type, "ppc970") == 0) {
+      part_ = PPC_G5;
+    } else if (strcmp(auxv_cpu_type, "ppc7450") == 0) {
+      part_ = PPC_G4;
+    } else if (strcmp(auxv_cpu_type, "pa6t") == 0) {
+      part_ = PPC_PA6T;
+    }
+  }
+
+  if (auxv_cache_line_size > 0) {
+    cache_line_size_ = auxv_cache_line_size;
+  }
+#endif
+
 #endif
 }
 
 } }  // namespace v8::base