when open macro GENERATED_CODE_COVERAGE, fix compiler error and fd leak

src/x87/assembler-x87.cc

Index: src/x87/assembler-x87.cc
diff --git a/src/x87/assembler-x87.cc b/src/x87/assembler-x87.cc
index 557be236ba062f1b3d3495d5cd3d46b51c00bc01..a599c7fb415418f2103f13b91c09536c6d00d47d 100644
--- a/src/x87/assembler-x87.cc
+++ b/src/x87/assembler-x87.cc
@@ -230,6 +230,7 @@ Register Operand::reg() const {
 
 #ifdef GENERATED_CODE_COVERAGE
 static void InitCoverageLog();
+static void DeinitCoverageLog();
 #endif
 
 Assembler::Assembler(Isolate* isolate, void* buffer, int buffer_size)
@@ -251,6 +252,11 @@ Assembler::Assembler(Isolate* isolate, void* buffer, int buffer_size)
 #endif
 }
 
+Assembler::~Assembler() {
+#ifdef GENERATED_CODE_COVERAGE
+  DeinitCoverageLog();
+#endif
+}
 
 void Assembler::GetCode(CodeDesc* desc) {
   // Finalize code (at this point overflow() may be true, but the gap ensures
@@ -2005,11 +2011,17 @@ static FILE* coverage_log = NULL;
 
 static void InitCoverageLog() {
   char* file_name = getenv("V8_GENERATED_CODE_COVERAGE_LOG");
-  if (file_name != NULL) {
+  if (file_name != NULL && NULL == coverage_log) {
     coverage_log = fopen(file_name, "aw+");
   }
 }
 
+static void DeinitCoverageLog() {
+	if (coverage_log != NULL) {
+		fclose(coverage_log);
+		coverage_log = NULL;
+	}
+}
 
 void LogGeneratedCodeCoverage(const char* file_line) {
   const char* return_address = (&file_line)[-1];