[llvm] [IR] Fix ignoring `non-global-value-max-name-size` in `ValueSymbolTab… (PR #89057)

[Daniil Fukalov via llvm-commits]

https://github.com/dfukalov updated https://github.com/llvm/llvm-project/pull/89057

>From daa21880e1455eb25abddbe11fdabd455172646f Mon Sep 17 00:00:00 2001
From: dfukalov <1671137+dfukalov at users.noreply.github.com>
Date: Wed, 17 Apr 2024 13:43:36 +0200
Subject: [PATCH 1/2] [IR] Fix ignoring `non-global-value-max-name-size` in
 `ValueSymbolTable::makeUniqueName()`.

E.g. during inlining new symbol name can be duplicated and then
`ValueSymbolTable::makeUniqueName()` will add unique suffix, exceeding
the `non-global-value-max-name-size` restriction.
---
 llvm/lib/IR/ValueSymbolTable.cpp              | 31 ++++++++++++-------
 .../non-global-value-max-name-size-2.ll       | 23 ++++++++++++++
 2 files changed, 43 insertions(+), 11 deletions(-)
 create mode 100644 llvm/test/Assembler/non-global-value-max-name-size-2.ll

diff --git a/llvm/lib/IR/ValueSymbolTable.cpp b/llvm/lib/IR/ValueSymbolTable.cpp
index 52f7ddcdc65a2b..7b4cecac9a2ccd 100644
--- a/llvm/lib/IR/ValueSymbolTable.cpp
+++ b/llvm/lib/IR/ValueSymbolTable.cpp
@@ -43,23 +43,32 @@ ValueSymbolTable::~ValueSymbolTable() {
 ValueName *ValueSymbolTable::makeUniqueName(Value *V,
                                             SmallString<256> &UniqueName) {
   unsigned BaseSize = UniqueName.size();
+  bool AppenDot = false;
+  if (auto *GV = dyn_cast<GlobalValue>(V)) {
+    // A dot is appended to mark it as clone during ABI demangling so that
+    // for example "_Z1fv" and "_Z1fv.1" both demangle to "f()", the second
+    // one being a clone.
+    // On NVPTX we cannot use a dot because PTX only allows [A-Za-z0-9_$] for
+    // identifiers. This breaks ABI demangling but at least ptxas accepts and
+    // compiles the program.
+    const Module *M = GV->getParent();
+    if (!(M && Triple(M->getTargetTriple()).isNVPTX()))
+      AppenDot = true;
+  }
+
   while (true) {
     // Trim any suffix off and append the next number.
     UniqueName.resize(BaseSize);
     raw_svector_ostream S(UniqueName);
-    if (auto *GV = dyn_cast<GlobalValue>(V)) {
-      // A dot is appended to mark it as clone during ABI demangling so that
-      // for example "_Z1fv" and "_Z1fv.1" both demangle to "f()", the second
-      // one being a clone.
-      // On NVPTX we cannot use a dot because PTX only allows [A-Za-z0-9_$] for
-      // identifiers. This breaks ABI demangling but at least ptxas accepts and
-      // compiles the program.
-      const Module *M = GV->getParent();
-      if (!(M && Triple(M->getTargetTriple()).isNVPTX()))
-        S << ".";
-    }
+    if (AppenDot)
+      S << ".";
     S << ++LastUnique;
 
+    // Retry if MaxNameSize has been exceeded.
+    if (MaxNameSize > -1 && UniqueName.size() > (unsigned)MaxNameSize) {
+      BaseSize -= UniqueName.size() - (unsigned)MaxNameSize;
+      continue;
+    }
     // Try insert the vmap entry with this suffix.
     auto IterBool = vmap.insert(std::make_pair(UniqueName.str(), V));
     if (IterBool.second)
diff --git a/llvm/test/Assembler/non-global-value-max-name-size-2.ll b/llvm/test/Assembler/non-global-value-max-name-size-2.ll
new file mode 100644
index 00000000000000..5eac003ddb4383
--- /dev/null
+++ b/llvm/test/Assembler/non-global-value-max-name-size-2.ll
@@ -0,0 +1,23 @@
+; RUN: opt < %s -S -passes='always-inline' -non-global-value-max-name-size=5 | opt -non-global-value-max-name-size=5 -passes=verify -disable-output
+
+; Opt should not generate too long name for labels during inlining.
+
+define internal i32 @inner(i32 %flag) alwaysinline {
+entry:
+  %icmp = icmp slt i32 %flag, 0
+  br i1 %icmp, label %one, label %two
+
+one:
+  ret i32 42
+
+two:
+  ret i32 44
+}
+
+define i32 @outer(i32 %x) {
+entry:
+  %call1 = call i32 @inner(i32 %x)
+  %call2 = call i32 @inner(i32 %x)
+  %ret = add i32 %call1, %call2
+  ret i32 %ret
+}
\ No newline at end of file

>From 0c376ad20206580b257032da0f9e9379a64aab3b Mon Sep 17 00:00:00 2001
From: dfukalov <1671137+dfukalov at users.noreply.github.com>
Date: Wed, 17 Apr 2024 14:54:56 +0200
Subject: [PATCH 2/2] Fix `Bitcode/value-with-long-name.ll` test

---
 llvm/lib/IR/ValueSymbolTable.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/IR/ValueSymbolTable.cpp b/llvm/lib/IR/ValueSymbolTable.cpp
index 7b4cecac9a2ccd..040a84228f11ae 100644
--- a/llvm/lib/IR/ValueSymbolTable.cpp
+++ b/llvm/lib/IR/ValueSymbolTable.cpp
@@ -65,7 +65,7 @@ ValueName *ValueSymbolTable::makeUniqueName(Value *V,
     S << ++LastUnique;
 
     // Retry if MaxNameSize has been exceeded.
-    if (MaxNameSize > -1 && UniqueName.size() > (unsigned)MaxNameSize) {
+    if (MaxNameSize > 0 && UniqueName.size() > (unsigned)MaxNameSize) {
       BaseSize -= UniqueName.size() - (unsigned)MaxNameSize;
       continue;
     }