Revert of MIPS: Fix 'Assembler support for internal references.' (patchset #1...

Revert of MIPS: Fix 'Assembler support for internal references.' (patchset #1 id:1 of https://codereview.chromium.org/922043005/)

Reason for revert:
Breaks http://build.chromium.org/p/chromium.fyi/builders/Android%20MIPS%20Builder%20(dbg)

Original issue's description:
> MIPS: Fix 'Assembler support for internal references.'
>
> Added new INTERNAL_REFERENCE_ENCODED RelocInfo type to differentiate MIPS existing use of internal references in instructions from the new raw pointer reference needed for dd(Label*).
>
> BUG=
> TEST=cctest/test-assembler-mips/jump_tables1, cctest/test-assembler-mips/jump_tables2, cctest/test-assembler-mips/jump_tables3, cctest/test-run-machops/RunSwitch1
>
> Committed: https://crrev.com/244ac6de8316259bc5878480e05348a369c08e2f
> Cr-Commit-Position: refs/heads/master@{#26651}

TBR=danno@chromium.org,bmeurer@chromium.org,jkummerow@chromium.org,paul.lind@imgtec.com,gergely.kis@imgtec.com,akos.palfi@imgtec.com,dusan.milosavljevic@imgtec.com,balazs.kilvady@imgtec.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/934623003

Cr-Commit-Position: refs/heads/master@{#26675}

src/assembler.h

@@ -393,11 +393,6 @@ class RelocInfo {
     NONE64,             // never recorded 64-bit value
     CODE_AGE_SEQUENCE,  // Not stored in RelocInfo array, used explictly by
                         // code aging.
-
-    // Encoded internal reference, used only on MIPS and MIPS64.
-    // Re-uses previous ARM-only encoding, to fit in RealRelocMode space.
-    INTERNAL_REFERENCE_ENCODED = CONST_POOL,
-
     FIRST_REAL_RELOC_MODE = CODE_TARGET,
     LAST_REAL_RELOC_MODE = VENEER_POOL,
     FIRST_PSEUDO_RELOC_MODE = CODE_AGE_SEQUENCE,
@@ -470,9 +465,6 @@ class RelocInfo {
   static inline bool IsInternalReference(Mode mode) {
     return mode == INTERNAL_REFERENCE;
   }
-  static inline bool IsInternalReferenceEncoded(Mode mode) {
-    return mode == INTERNAL_REFERENCE_ENCODED;
-  }
   static inline bool IsDebugBreakSlot(Mode mode) {
     return mode == DEBUG_BREAK_SLOT;
   }

src/mips/assembler-mips-inl.h

@@ -126,10 +126,10 @@ void RelocInfo::apply(intptr_t delta, ICacheFlushMode icache_flush_mode) {
       Assembler::JumpLabelToJumpRegister(pc_);
     }
   }
-  if (IsInternalReference(rmode_) || IsInternalReferenceEncoded(rmode_)) {
+  if (IsInternalReference(rmode_)) {
     // Absolute code pointer inside code object moves with the code object.
     byte* p = reinterpret_cast<byte*>(pc_);
-    int count = Assembler::RelocateInternalReference(rmode_, p, delta);
+    int count = Assembler::RelocateInternalReference(p, delta);
     CpuFeatures::FlushICache(p, count * sizeof(uint32_t));
   }
 }

src/mips/assembler-mips.h

@@ -38,8 +38,6 @@
 
 #include <stdio.h>
 
-#include <tr1/unordered_set>
-
 #include "src/assembler.h"
 #include "src/mips/constants-mips.h"
 #include "src/serialize.h"
@@ -1023,8 +1021,7 @@ class Assembler : public AssemblerBase {
   void RecordDeoptReason(const int reason, const int raw_position);
 
 
-  static int RelocateInternalReference(RelocInfo::Mode rmode, byte* pc,
-                                       intptr_t pc_delta);
+  static int RelocateInternalReference(byte* pc, intptr_t pc_delta);
 
   // Writes a single byte or word of data in the code stream.  Used for
   // inline tables, e.g., jump-tables.
@@ -1129,10 +1126,10 @@ class Assembler : public AssemblerBase {
   int32_t buffer_space() const { return reloc_info_writer.pos() - pc_; }
 
   // Decode branch instruction at pos and return branch target pos.
-  int target_at(int32_t pos, bool is_internal);
+  int target_at(int32_t pos);
 
   // Patch branch instruction at pos to branch to given branch target pos.
-  void target_at_put(int32_t pos, int32_t target_pos, bool is_internal);
+  void target_at_put(int32_t pos, int32_t target_pos);
 
   // Say if we need to relocate with this mode.
   bool MustUseReg(RelocInfo::Mode rmode);
@@ -1301,7 +1298,7 @@ class Assembler : public AssemblerBase {
   // Labels.
   void print(Label* L);
   void bind_to(Label* L, int pos);
-  void next(Label* L, bool is_internal);
+  void next(Label* L);
 
   // One trampoline consists of:
   // - space for trampoline slots,
@@ -1366,10 +1363,6 @@ class Assembler : public AssemblerBase {
   static const int kMaxBranchOffset = (1 << (18 - 1)) - 1;
   static const int kInvalidSlotPos = -1;
 
-  // Internal reference positions, required for unbounded internal reference
-  // labels.
-  std::tr1::unordered_set<int> internal_reference_positions_;
-
   Trampoline trampoline_;
   bool internal_trampoline_exception_;
 

src/mips/constants-mips.h

@@ -339,6 +339,7 @@ enum Opcode {
 
   DADDI     =   ((3 << 3) + 0) << kOpcodeShift,  // This is also BNEC.
   SPECIAL2  =   ((3 << 3) + 4) << kOpcodeShift,
+  LABEL     =   ((3 << 3) + 5) << kOpcodeShift,
   SPECIAL3  =   ((3 << 3) + 7) << kOpcodeShift,
 
   LB        =   ((4 << 3) + 0) << kOpcodeShift,

src/mips/macro-assembler-mips.cc

@@ -3087,7 +3087,7 @@ void MacroAssembler::J(Label* L, BranchDelaySlot bdslot) {
   { BlockGrowBufferScope block_buf_growth(this);
     // Buffer growth (and relocation) must be blocked for internal references
     // until associated instructions are emitted and available to be patched.
-    RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE_ENCODED);
+    RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE);
     j(imm28);
   }
   // Emit a nop in the branch delay slot if required.
@@ -3104,7 +3104,7 @@ void MacroAssembler::Jr(Label* L, BranchDelaySlot bdslot) {
   { BlockGrowBufferScope block_buf_growth(this);
     // Buffer growth (and relocation) must be blocked for internal references
     // until associated instructions are emitted and available to be patched.
-    RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE_ENCODED);
+    RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE);
     lui(at, (imm32 & kHiMask) >> kLuiShift);
     ori(at, at, (imm32 & kImm16Mask));
   }
@@ -3124,7 +3124,7 @@ void MacroAssembler::Jalr(Label* L, BranchDelaySlot bdslot) {
   { BlockGrowBufferScope block_buf_growth(this);
     // Buffer growth (and relocation) must be blocked for internal references
     // until associated instructions are emitted and available to be patched.
-    RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE_ENCODED);
+    RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE);
     lui(at, (imm32 & kHiMask) >> kLuiShift);
     ori(at, at, (imm32 & kImm16Mask));
   }