Fix the substitution of neon arrangement specifiers

NEONFormatDecoder::Substitute function utilizes snprintf()
to substitute arrangement specifier into a format string.
Some instruction format strings (e.i. ld4r) are specified
with '%n$' positional parameter fields, but on Windows
snprintf function doesn't support these parameters.
NEONFormatDecoder logic is extended to handle four parameters
in order to avoid using positional parameters.

Bug: v8:10365
Change-Id: I79d4014c6b45d698ca47090a74c30e4eae856334
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2148776Reviewed-by: Martyn Capewell <martyn.capewell@arm.com>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67201}

src/codegen/arm64/instructions-arm64.cc

@@ -343,6 +343,10 @@ void NEONFormatDecoder::SetFormatMaps(const NEONFormatMap* format0,
   formats_[0] = format0;
   formats_[1] = (format1 == nullptr) ? formats_[0] : format1;
   formats_[2] = (format2 == nullptr) ? formats_[1] : format2;
+  // Support four parameters form (e.i. ld4r)
+  // to avoid using positional arguments in DisassemblingDecoder.
+  // See: https://crbug.com/v8/10365
+  formats_[3] = formats_[2];
 }
 
 void NEONFormatDecoder::SetFormatMap(unsigned index,
@@ -353,15 +357,18 @@ void NEONFormatDecoder::SetFormatMap(unsigned index,
 }
 
 const char* NEONFormatDecoder::SubstitutePlaceholders(const char* string) {
-  return Substitute(string, kPlaceholder, kPlaceholder, kPlaceholder);
+  return Substitute(string, kPlaceholder, kPlaceholder, kPlaceholder,
+                    kPlaceholder);
 }
 
 const char* NEONFormatDecoder::Substitute(const char* string,
                                           SubstitutionMode mode0,
                                           SubstitutionMode mode1,
-                                          SubstitutionMode mode2) {
+                                          SubstitutionMode mode2,
+                                          SubstitutionMode mode3) {
   snprintf(form_buffer_, sizeof(form_buffer_), string, GetSubstitute(0, mode0),
-           GetSubstitute(1, mode1), GetSubstitute(2, mode2));
+           GetSubstitute(1, mode1), GetSubstitute(2, mode2),
+           GetSubstitute(3, mode3));
   return form_buffer_;
 }
 

src/codegen/arm64/instructions-arm64.h

@@ -619,7 +619,8 @@ class NEONFormatDecoder {
   // substitution mode.
   const char* Substitute(const char* string, SubstitutionMode mode0 = kFormat,
                          SubstitutionMode mode1 = kFormat,
-                         SubstitutionMode mode2 = kFormat);
+                         SubstitutionMode mode2 = kFormat,
+                         SubstitutionMode mode3 = kFormat);
 
   // Append a "2" to a mnemonic string based of the state of the Q bit.
   const char* Mnemonic(const char* mnemonic);
@@ -738,7 +739,7 @@ class NEONFormatDecoder {
   uint8_t PickBits(const uint8_t bits[]);
 
   Instr instrbits_;
-  const NEONFormatMap* formats_[3];
+  const NEONFormatMap* formats_[4];
   char form_buffer_[64];
   char mne_buffer_[16];
 };

src/diagnostics/arm64/disasm-arm64.cc

@@ -2252,10 +2252,10 @@ void DisassemblingDecoder::VisitNEONExtract(Instruction* instr) {
 void DisassemblingDecoder::VisitNEONLoadStoreMultiStruct(Instruction* instr) {
   const char* mnemonic = nullptr;
   const char* form = nullptr;
-  const char* form_1v = "{'Vt.%1$s}, ['Xns]";
-  const char* form_2v = "{'Vt.%1$s, 'Vt2.%1$s}, ['Xns]";
-  const char* form_3v = "{'Vt.%1$s, 'Vt2.%1$s, 'Vt3.%1$s}, ['Xns]";
-  const char* form_4v = "{'Vt.%1$s, 'Vt2.%1$s, 'Vt3.%1$s, 'Vt4.%1$s}, ['Xns]";
+  const char* form_1v = "{'Vt.%s}, ['Xns]";
+  const char* form_2v = "{'Vt.%s, 'Vt2.%s}, ['Xns]";
+  const char* form_3v = "{'Vt.%s, 'Vt2.%s, 'Vt3.%s}, ['Xns]";
+  const char* form_4v = "{'Vt.%s, 'Vt2.%s, 'Vt3.%s, 'Vt4.%s}, ['Xns]";
   NEONFormatDecoder nfd(instr, NEONFormatDecoder::LoadStoreFormatMap());
 
   switch (instr->Mask(NEONLoadStoreMultiStructMask)) {
@@ -2349,11 +2349,10 @@ void DisassemblingDecoder::VisitNEONLoadStoreMultiStructPostIndex(
     Instruction* instr) {
   const char* mnemonic = nullptr;
   const char* form = nullptr;
-  const char* form_1v = "{'Vt.%1$s}, ['Xns], 'Xmr1";
-  const char* form_2v = "{'Vt.%1$s, 'Vt2.%1$s}, ['Xns], 'Xmr2";
-  const char* form_3v = "{'Vt.%1$s, 'Vt2.%1$s, 'Vt3.%1$s}, ['Xns], 'Xmr3";
-  const char* form_4v =
-      "{'Vt.%1$s, 'Vt2.%1$s, 'Vt3.%1$s, 'Vt4.%1$s}, ['Xns], 'Xmr4";
+  const char* form_1v = "{'Vt.%s}, ['Xns], 'Xmr1";
+  const char* form_2v = "{'Vt.%s, 'Vt2.%s}, ['Xns], 'Xmr2";
+  const char* form_3v = "{'Vt.%s, 'Vt2.%s, 'Vt3.%s}, ['Xns], 'Xmr3";
+  const char* form_4v = "{'Vt.%s, 'Vt2.%s, 'Vt3.%s, 'Vt4.%s}, ['Xns], 'Xmr4";
   NEONFormatDecoder nfd(instr, NEONFormatDecoder::LoadStoreFormatMap());
 
   switch (instr->Mask(NEONLoadStoreMultiStructPostIndexMask)) {
@@ -2561,7 +2560,7 @@ void DisassemblingDecoder::VisitNEONLoadStoreSingleStruct(Instruction* instr) {
       break;
     case NEON_LD4R:
       mnemonic = "ld4r";
-      form = "{'Vt.%1$s, 'Vt2.%1$s, 'Vt3.%1$s, 'Vt4.%1$s}, ['Xns]";
+      form = "{'Vt.%s, 'Vt2.%s, 'Vt3.%s, 'Vt4.%s}, ['Xns]";
       break;
     default:
       break;
@@ -2722,7 +2721,7 @@ void DisassemblingDecoder::VisitNEONLoadStoreSingleStructPostIndex(
       break;
     case NEON_LD4R_post:
       mnemonic = "ld4r";
-      form = "{'Vt.%1$s, 'Vt2.%1$s, 'Vt3.%1$s, 'Vt4.%1$s}, ['Xns], 'Xmz4";
+      form = "{'Vt.%s, 'Vt2.%s, 'Vt3.%s, 'Vt4.%s}, ['Xns], 'Xmz4";
       break;
     default:
       break;