Remove X64::CodeGenerator::ifBlock and JccBlock

ifBlock() is the same as a different utility function called
ifThen, and only had one callsite.

JccBlock only had one callsite, and can be done cleanly with
lambda-style

Reviewed By: @swtaarrs

Differential Revision: D1276611

hphp/runtime/vm/jit/code-gen-x64.cpp

@@ -5877,8 +5877,8 @@ void CodeGenerator::cgDbgAssertRetAddr(IRInstruction* inst) {
     m_as.emitImmReg(imm, m_rScratch);
     m_as.cmpq(m_rScratch, *rsp);
   }
-  ifBlock(CC_NE, [&](Asm& a) {
-     a.ud2();
+  ifThen(m_as, CC_NE, [&] {
+     m_as.ud2();
   });
 }
 

hphp/runtime/vm/jit/code-gen-x64.h

@@ -267,14 +267,6 @@ struct CodeGenerator {
     }
   }
 
-  template <class Then>
-  void ifBlock(ConditionCode cc, Then thenBlock) {
-    Label done;
-    m_as.jcc8(ccNegate(cc), done);
-    thenBlock(m_as);
-    asm_label(m_as, done);
-  }
-
   // Generate an if-then-else block
   template <class Then, class Else>
   void ifThenElse(Asm& a, ConditionCode cc, Then thenBlock, Else elseBlock) {

hphp/runtime/vm/jit/func-prologues-x64.cpp

@@ -226,10 +226,11 @@ SrcKey emitPrologueWork(Func* func, int nPassed) {
 
     if (!(func->attrs() & AttrStatic)) {
       a.shrq(1, rAsm);
-      JccBlock<CC_BE> ifRealThis(a);
-      a.shlq(1, rAsm);
-      // XXX can objects be static?
-      emitIncRefCheckNonStatic(a, rAsm, KindOfObject);
+      ifThen(a, CC_NBE, [&] {
+        a.shlq(1, rAsm);
+        // XXX can objects be static?
+        emitIncRefCheckNonStatic(a, rAsm, KindOfObject);
+      });
     }
 
     // Put in the correct context

hphp/runtime/vm/jit/mc-generator-internal.h

@@ -55,31 +55,6 @@ struct Jcc32 {
   }
 };
 
-// JccBlock --
-//   A raw condition-code block; assumes whatever comparison or ALU op
-//   that sets the Jcc has already executed.
-template <ConditionCode Jcc, typename J=Jcc8>
-struct JccBlock {
-  mutable X64Assembler* m_a;
-  TCA m_jcc;
-
-  explicit JccBlock(X64Assembler& a)
-    : m_a(&a) {
-    m_jcc = a.frontier();
-    J::branch(a, Jcc, m_a->frontier());
-  }
-
-  ~JccBlock() {
-    if (m_a) {
-      J::patch(*m_a, m_jcc, m_a->frontier());
-    }
-  }
-
-private:
-  JccBlock(const JccBlock&);
-  JccBlock& operator=(const JccBlock&);
-};
-
 // A CondBlock is an RAII structure for emitting conditional code. It
 // compares the source register at fieldOffset with fieldValue, and
 // conditionally branches over the enclosing block of assembly on the