From 1e7883a659bd332879512de5da0d018fa2189f02 Mon Sep 17 00:00:00 2001
From: mmc28a <78873583+mmc28a@users.noreply.github.com>
Date: Wed, 29 Jan 2025 17:45:49 +0000
Subject: [PATCH] Remove printf positional argument requirements from
 disassembler (#125)

Positional arguments to printf (eg. %1$s) are not allowed on Windows, so remove
uses of this in the disassembler, replacing them with an extension to the
existing NEONFormatDecoder class.

Patch prompted by https://github.com/Linaro/vixl/pull/122
---
 src/aarch64/disasm-aarch64.cc      | 21 ++++++++++-----------
 src/aarch64/instructions-aarch64.h | 16 +++++++++++-----
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/src/aarch64/disasm-aarch64.cc b/src/aarch64/disasm-aarch64.cc
index 7e1ab465..5bcee747 100644
--- a/src/aarch64/disasm-aarch64.cc
+++ b/src/aarch64/disasm-aarch64.cc
@@ -2733,10 +2733,10 @@ void Disassembler::VisitNEONExtract(const Instruction *instr) {
 void Disassembler::VisitNEONLoadStoreMultiStruct(const Instruction *instr) {
   const char *mnemonic = NULL;
   const char *form = NULL;
-  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)) {
@@ -2831,11 +2831,10 @@ void Disassembler::VisitNEONLoadStoreMultiStructPostIndex(
     const Instruction *instr) {
   const char *mnemonic = NULL;
   const char *form = NULL;
-  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)) {
@@ -3038,7 +3037,7 @@ void Disassembler::VisitNEONLoadStoreSingleStruct(const 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;
@@ -3198,7 +3197,7 @@ void Disassembler::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;
diff --git a/src/aarch64/instructions-aarch64.h b/src/aarch64/instructions-aarch64.h
index ad0ba582..00aeb3cf 100644
--- a/src/aarch64/instructions-aarch64.h
+++ b/src/aarch64/instructions-aarch64.h
@@ -856,11 +856,13 @@ class NEONFormatDecoder {
   // Set the format mapping for all or individual substitutions.
   void SetFormatMaps(const NEONFormatMap* format0,
                      const NEONFormatMap* format1 = NULL,
-                     const NEONFormatMap* format2 = NULL) {
+                     const NEONFormatMap* format2 = NULL,
+                     const NEONFormatMap* format3 = NULL) {
     VIXL_ASSERT(format0 != NULL);
     formats_[0] = format0;
     formats_[1] = (format1 == NULL) ? formats_[0] : format1;
     formats_[2] = (format2 == NULL) ? formats_[1] : format2;
+    formats_[3] = (format3 == NULL) ? formats_[2] : format3;
   }
   void SetFormatMap(unsigned index, const NEONFormatMap* format) {
     VIXL_ASSERT(index <= ArrayLength(formats_));
@@ -879,12 +881,15 @@ class NEONFormatDecoder {
   const char* Substitute(const char* string,
                          SubstitutionMode mode0 = kFormat,
                          SubstitutionMode mode1 = kFormat,
-                         SubstitutionMode mode2 = kFormat) {
+                         SubstitutionMode mode2 = kFormat,
+                         SubstitutionMode mode3 = kFormat) {
     const char* subst0 = GetSubstitute(0, mode0);
     const char* subst1 = GetSubstitute(1, mode1);
     const char* subst2 = GetSubstitute(2, mode2);
+    const char* subst3 = GetSubstitute(3, mode3);
 
-    if ((subst0 == NULL) || (subst1 == NULL) || (subst2 == NULL)) {
+    if ((subst0 == NULL) || (subst1 == NULL) || (subst2 == NULL) ||
+        (subst3 == NULL)) {
       return NULL;
     }
 
@@ -893,7 +898,8 @@ class NEONFormatDecoder {
              string,
              subst0,
              subst1,
-             subst2);
+             subst2,
+             subst3);
     return form_buffer_;
   }
 
@@ -1131,7 +1137,7 @@ class NEONFormatDecoder {
   }
 
   Instr instrbits_;
-  const NEONFormatMap* formats_[3];
+  const NEONFormatMap* formats_[4];
   char form_buffer_[64];
   char mne_buffer_[16];
 };