MIPS: Fix label position types in binding code.

Also some target_at and target_at_put uniformed on mips and mips64.

BUG=

Review URL: https://codereview.chromium.org/942123002

Cr-Commit-Position: refs/heads/master@{#26785}

src/mips/assembler-mips.cc

@@ -663,14 +663,14 @@ bool Assembler::IsAndImmediate(Instr instr) {
 }
 
 
-int Assembler::target_at(int32_t pos, bool is_internal) {
+int Assembler::target_at(int pos, bool is_internal) {
   Instr instr = instr_at(pos);
   if (is_internal) {
     if (instr == 0) {
       return kEndOfChain;
     } else {
       int32_t instr_address = reinterpret_cast<int32_t>(buffer_ + pos);
-      int32_t delta = instr_address - instr;
+      int delta = static_cast<int>(instr_address - instr);
       DCHECK(pos > delta);
       return pos - delta;
     }
@@ -684,6 +684,8 @@ int Assembler::target_at(int32_t pos, bool is_internal) {
        return (imm18 + pos);
      }
   }
+  // Check we have a branch or jump instruction.
+  DCHECK(IsBranch(instr) || IsJ(instr) || IsLui(instr));
   // Do NOT change this to <<2. We rely on arithmetic shifts here, assuming
   // the compiler uses arithmectic shifts for signed integers.
   if (IsBranch(instr)) {
@@ -711,7 +713,7 @@ int Assembler::target_at(int32_t pos, bool is_internal) {
       DCHECK(pos > delta);
       return pos - delta;
     }
-  } else if (IsJ(instr)) {
+  } else {
     int32_t imm28 = (instr & static_cast<int32_t>(kImm26Mask)) << 2;
     if (imm28 == kEndOfJumpChain) {
       // EndOfChain sentinel is returned directly, not relative to pc or pos.
@@ -719,13 +721,10 @@ int Assembler::target_at(int32_t pos, bool is_internal) {
     } else {
       uint32_t instr_address = reinterpret_cast<int32_t>(buffer_ + pos);
       instr_address &= kImm28Mask;
-      int32_t delta = instr_address - imm28;
+      int delta = static_cast<int>(instr_address - imm28);
       DCHECK(pos > delta);
       return pos - delta;
     }
-  } else {
-    UNREACHABLE();
-    return 0;
   }
 }
 
@@ -747,6 +746,7 @@ void Assembler::target_at_put(int32_t pos, int32_t target_pos,
     return;
   }
 
+  DCHECK(IsBranch(instr) || IsJ(instr) || IsLui(instr));
   if (IsBranch(instr)) {
     int32_t imm18 = target_pos - (pos + kBranchPCOffset);
     DCHECK((imm18 & 3) == 0);
@@ -770,7 +770,7 @@ void Assembler::target_at_put(int32_t pos, int32_t target_pos,
                  instr_lui | ((imm & kHiMask) >> kLuiShift));
     instr_at_put(pos + 1 * Assembler::kInstrSize,
                  instr_ori | (imm & kImm16Mask));
-  } else if (IsJ(instr)) {
+  } else {
     uint32_t imm28 = reinterpret_cast<uint32_t>(buffer_) + target_pos;
     imm28 &= kImm28Mask;
     DCHECK((imm28 & 3) == 0);
@@ -780,8 +780,6 @@ void Assembler::target_at_put(int32_t pos, int32_t target_pos,
     DCHECK(is_uint26(imm26));
 
     instr_at_put(pos, instr | (imm26 & kImm26Mask));
-  } else {
-    UNREACHABLE();
   }
 }
 

src/mips/assembler-mips.h

@@ -1129,10 +1129,10 @@ 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(int pos, bool is_internal);
 
   // 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(int pos, int target_pos, bool is_internal);
 
   // Say if we need to relocate with this mode.
   bool MustUseReg(RelocInfo::Mode rmode);

src/mips64/assembler-mips64.cc

@@ -32,7 +32,6 @@
 // modified significantly by Google Inc.
 // Copyright 2012 the V8 project authors. All rights reserved.
 
-
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_MIPS64
@@ -635,7 +634,7 @@ bool Assembler::IsAndImmediate(Instr instr) {
 }
 
 
-int64_t Assembler::target_at(int64_t pos, bool is_internal) {
+int Assembler::target_at(int pos, bool is_internal) {
   if (is_internal) {
     int64_t* p = reinterpret_cast<int64_t*>(buffer_ + pos);
     int64_t address = *p;
@@ -643,7 +642,8 @@ int64_t Assembler::target_at(int64_t pos, bool is_internal) {
       return kEndOfChain;
     } else {
       int64_t instr_address = reinterpret_cast<int64_t>(p);
-      int64_t delta = instr_address - address;
+      DCHECK(instr_address - address < INT_MAX);
+      int delta = static_cast<int>(instr_address - address);
       DCHECK(pos > delta);
       return pos - delta;
     }
@@ -689,7 +689,8 @@ int64_t Assembler::target_at(int64_t pos, bool is_internal) {
       return kEndOfChain;
     } else {
       uint64_t instr_address = reinterpret_cast<int64_t>(buffer_ + pos);
-      int64_t delta = instr_address - imm;
+      DCHECK(instr_address - imm < INT_MAX);
+      int delta = static_cast<int>(instr_address - imm);
       DCHECK(pos > delta);
       return pos - delta;
     }
@@ -701,7 +702,7 @@ int64_t Assembler::target_at(int64_t pos, bool is_internal) {
     } else {
       uint64_t instr_address = reinterpret_cast<int64_t>(buffer_ + pos);
       instr_address &= kImm28Mask;
-      int64_t delta = instr_address - imm28;
+      int delta = static_cast<int>(instr_address - imm28);
       DCHECK(pos > delta);
       return pos - delta;
     }
@@ -709,8 +710,7 @@ int64_t Assembler::target_at(int64_t pos, bool is_internal) {
 }
 
 
-void Assembler::target_at_put(int64_t pos, int64_t target_pos,
-                              bool is_internal) {
+void Assembler::target_at_put(int pos, int target_pos, bool is_internal) {
   if (is_internal) {
     uint64_t imm = reinterpret_cast<uint64_t>(buffer_) + target_pos;
     *reinterpret_cast<uint64_t*>(buffer_ + pos) = imm;
@@ -796,7 +796,7 @@ void Assembler::print(Label* L) {
 
 void Assembler::bind_to(Label* L, int pos) {
   DCHECK(0 <= pos && pos <= pc_offset());  // Must have valid binding position.
-  int32_t trampoline_pos = kInvalidSlotPos;
+  int trampoline_pos = kInvalidSlotPos;
   bool is_internal = false;
   if (L->is_linked() && !trampoline_emitted_) {
     unbound_labels_count_--;
@@ -804,8 +804,8 @@ void Assembler::bind_to(Label* L, int pos) {
   }
 
   while (L->is_linked()) {
-    int32_t fixup_pos = L->pos();
-    int32_t dist = pos - fixup_pos;
+    int fixup_pos = L->pos();
+    int dist = pos - fixup_pos;
     is_internal = internal_reference_positions_.find(fixup_pos) !=
                   internal_reference_positions_.end();
     next(L, is_internal);  // Call next before overwriting link with target at

src/mips64/assembler-mips64.h

@@ -1168,10 +1168,10 @@ class Assembler : public AssemblerBase {
   int64_t buffer_space() const { return reloc_info_writer.pos() - pc_; }
 
   // Decode branch instruction at pos and return branch target pos.
-  int64_t target_at(int64_t pos, bool is_internal);
+  int target_at(int pos, bool is_internal);
 
   // Patch branch instruction at pos to branch to given branch target pos.
-  void target_at_put(int64_t pos, int64_t target_pos, bool is_internal);
+  void target_at_put(int pos, int target_pos, bool is_internal);
 
   // Say if we need to relocate with this mode.
   bool MustUseReg(RelocInfo::Mode rmode);