[llvm] [GlobalISel] Prefix MatchTable Lines with their Index (PR #125845)

[Pierre van Houtryve via llvm-commits]

https://github.com/Pierre-vh updated https://github.com/llvm/llvm-project/pull/125845

>From 835576db2f011eaa5b09271852729f46d2c9617d Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Wed, 5 Feb 2025 13:07:21 +0100
Subject: [PATCH 1/4] [GlobalISel] Prefix MatchTable Lines with their Index

Fixes #119177
---
 .../GlobalISel/GlobalISelMatchTable.cpp       | 23 ++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
index 8564bf8d2d91ba5..9083ce7c86a4723 100644
--- a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
+++ b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
@@ -286,11 +286,25 @@ MatchTableRecord MatchTable::JumpTarget(unsigned LabelID) {
 void MatchTable::emitUse(raw_ostream &OS) const { OS << "MatchTable" << ID; }
 
 void MatchTable::emitDeclaration(raw_ostream &OS) const {
-  unsigned Indentation = 4;
+  static constexpr unsigned BaseIndent = 4;
+  unsigned Indentation = 0;
   OS << "  constexpr static uint8_t MatchTable" << ID << "[] = {";
   LineBreak.emit(OS, true, *this);
-  OS << std::string(Indentation, ' ');
 
+  const unsigned NumColsForIdx = llvm::to_string(CurrentSize).size();
+
+  unsigned CurIndex = 0;
+  const auto BeginLine = [&](){
+    OS << std::string(BaseIndent, ' ');
+    // To keep the /* index */ column consistent, pad
+    // the string at the start so we can always fit the
+    // exact number of characters to print the largest possible index.
+    std::string IdxStr = llvm::to_string(CurIndex);
+    OS << " /* " << std::string(NumColsForIdx - IdxStr.size(), ' ') << IdxStr << " */ ";
+    OS << std::string(Indentation, ' ');
+  };
+
+  BeginLine();
   for (auto I = Contents.begin(), E = Contents.end(); I != E; ++I) {
     bool LineBreakIsNext = false;
     const auto &NextI = std::next(I);
@@ -306,11 +320,14 @@ void MatchTable::emitDeclaration(raw_ostream &OS) const {
 
     I->emit(OS, LineBreakIsNext, *this);
     if (I->Flags & MatchTableRecord::MTRF_LineBreakFollows)
-      OS << std::string(Indentation, ' ');
+      BeginLine();
 
     if (I->Flags & MatchTableRecord::MTRF_Outdent)
       Indentation -= 2;
+
+    CurIndex += I->size();
   }
+  assert(CurIndex == CurrentSize);
   OS << "}; // Size: " << CurrentSize << " bytes\n";
 }
 

>From 8285c1b7d08fe3a1121cf051e3be5a2b666c948a Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Wed, 5 Feb 2025 13:11:52 +0100
Subject: [PATCH 2/4] clang-format

---
 .../TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp      | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
index 9083ce7c86a4723..6b4cef18245376f 100644
--- a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
+++ b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
@@ -294,13 +294,14 @@ void MatchTable::emitDeclaration(raw_ostream &OS) const {
   const unsigned NumColsForIdx = llvm::to_string(CurrentSize).size();
 
   unsigned CurIndex = 0;
-  const auto BeginLine = [&](){
+  const auto BeginLine = [&]() {
     OS << std::string(BaseIndent, ' ');
     // To keep the /* index */ column consistent, pad
     // the string at the start so we can always fit the
     // exact number of characters to print the largest possible index.
     std::string IdxStr = llvm::to_string(CurIndex);
-    OS << " /* " << std::string(NumColsForIdx - IdxStr.size(), ' ') << IdxStr << " */ ";
+    OS << " /* " << std::string(NumColsForIdx - IdxStr.size(), ' ') << IdxStr
+       << " */ ";
     OS << std::string(Indentation, ' ');
   };
 

>From 4e9e20f04f8da48592e4802656cf9c0763764e8f Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Thu, 6 Feb 2025 12:41:39 +0100
Subject: [PATCH 3/4] Use OS.indent() + add comments

---
 .../Common/GlobalISel/GlobalISelMatchTable.cpp       | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
index 6b4cef18245376f..db7156f00e16bbd 100644
--- a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
+++ b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
@@ -291,18 +291,20 @@ void MatchTable::emitDeclaration(raw_ostream &OS) const {
   OS << "  constexpr static uint8_t MatchTable" << ID << "[] = {";
   LineBreak.emit(OS, true, *this);
 
+  // We want to display the table index of each line in a consistent
+  // manner. It has to appear as a column on the left side of the table.
+  // To determine how wide the column needs to be, check how many characters
+  // we need to fit the largest possible index in the current table.
   const unsigned NumColsForIdx = llvm::to_string(CurrentSize).size();
 
   unsigned CurIndex = 0;
   const auto BeginLine = [&]() {
-    OS << std::string(BaseIndent, ' ');
-    // To keep the /* index */ column consistent, pad
-    // the string at the start so we can always fit the
-    // exact number of characters to print the largest possible index.
+    OS.indent(BaseIndent);
     std::string IdxStr = llvm::to_string(CurIndex);
+    // Pad the string with spaces to keep the size of the prefix consistent.
     OS << " /* " << std::string(NumColsForIdx - IdxStr.size(), ' ') << IdxStr
        << " */ ";
-    OS << std::string(Indentation, ' ');
+    OS.indent(Indentation);
   };
 
   BeginLine();

>From c3abfcdbbe22483acc0e5eb37de8b68c30061a20 Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Thu, 6 Feb 2025 12:50:43 +0100
Subject: [PATCH 4/4] more OS.indent()

---
 .../utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
index db7156f00e16bbd..21db090f62cced3 100644
--- a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
+++ b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp
@@ -302,8 +302,8 @@ void MatchTable::emitDeclaration(raw_ostream &OS) const {
     OS.indent(BaseIndent);
     std::string IdxStr = llvm::to_string(CurIndex);
     // Pad the string with spaces to keep the size of the prefix consistent.
-    OS << " /* " << std::string(NumColsForIdx - IdxStr.size(), ' ') << IdxStr
-       << " */ ";
+    OS << " /* ";
+    OS.indent(NumColsForIdx - IdxStr.size()) << IdxStr << " */ ";
     OS.indent(Indentation);
   };