Portable Linux perf map formatting.

src/log.cc

Index: src/log.cc
diff --git a/src/log.cc b/src/log.cc
index e77799802156726b0630ce26452afc8b47ff53a1..da935d8af72345ffd7393383b13fcc8b17a96903 100644
--- a/src/log.cc
+++ b/src/log.cc
@@ -284,9 +284,15 @@ void PerfBasicLogger::LogRecordedBuffer(AbstractCode* code, SharedFunctionInfo*,
     return;
   }
 
-  base::OS::FPrint(perf_output_handle_, "%p %x %.*s\n",
-                   code->instruction_start(), code->instruction_size(), length,
-                   name);
+  // Linux perf expects hex literals without a leading 0x, while some
+  // implementations of printf might prepend one when using the %p format
+  // for pointers, leading to wrongly formatted JIT symbols maps.
+  //
+  // Instead, we use V8PRIxPTR format string and cast pointer to uintpr_t,
+  // so that we have control over the exact output format.
+  base::OS::FPrint(perf_output_handle_, "%" V8PRIxPTR " %x %.*s\n",
+                   reinterpret_cast<uintptr_t>(code->instruction_start()),
+                   code->instruction_size(), length, name);
 }
 
 // Low-level logging support.