[clang] [llvm] [llvm] Avoid resolving `.incbin` during symbol collection (PR #172920)

[Jan Svoboda via cfe-commits]

https://github.com/jansvoboda11 updated https://github.com/llvm/llvm-project/pull/172920

>From 32c3db2a5483a795b52a81732950ee6192f8a90b Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda at apple.com>
Date: Thu, 18 Dec 2025 14:03:11 -0800
Subject: [PATCH 1/2] [llvm] Avoid resolving `.incbin` during symbol collection

---
 clang/test/CodeGen/asm_incbin.c             | 8 ++++++++
 llvm/include/llvm/MC/MCParser/MCAsmParser.h | 4 ++++
 llvm/lib/MC/MCParser/AsmParser.cpp          | 3 +++
 llvm/lib/Object/ModuleSymbolTable.cpp       | 3 +++
 4 files changed, 18 insertions(+)
 create mode 100644 clang/test/CodeGen/asm_incbin.c

diff --git a/clang/test/CodeGen/asm_incbin.c b/clang/test/CodeGen/asm_incbin.c
new file mode 100644
index 0000000000000..9ad447a1dfc98
--- /dev/null
+++ b/clang/test/CodeGen/asm_incbin.c
@@ -0,0 +1,8 @@
+// RUN: split-file %s %t
+//--- foo.h
+//--- tu.c
+asm(".incbin \"foo.h\"");
+// RUN: cd %t
+// RUN: %clang -c -emit-llvm %t/tu.c -o %t/tu.ll
+// RUN: llvm-dis %t/tu.ll -o - | FileCheck %s
+// CHECK: module asm ".incbin \22foo.h\22"
diff --git a/llvm/include/llvm/MC/MCParser/MCAsmParser.h b/llvm/include/llvm/MC/MCParser/MCAsmParser.h
index 5d74b76592df9..678dc05d29b2a 100644
--- a/llvm/include/llvm/MC/MCParser/MCAsmParser.h
+++ b/llvm/include/llvm/MC/MCParser/MCAsmParser.h
@@ -150,6 +150,7 @@ class LLVM_ABI MCAsmParser {
   bool HadError = false;
 
   bool ShowParsedOperands = false;
+  bool ProcessIncbinFile = true;
 
 public:
   MCAsmParser(const MCAsmParser &) = delete;
@@ -176,6 +177,9 @@ class LLVM_ABI MCAsmParser {
   bool getShowParsedOperands() const { return ShowParsedOperands; }
   void setShowParsedOperands(bool Value) { ShowParsedOperands = Value; }
 
+  bool getProcessIncbinFile() const { return ProcessIncbinFile; }
+  void setProcessIncbinFile(bool Value) { ProcessIncbinFile = Value; }
+
   /// Run the parser on the input source buffer.
   virtual bool Run(bool NoInitialTextSection, bool NoFinalize = false) = 0;
 
diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 429cdae1fa1b6..c9639fcdafe53 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -848,6 +848,9 @@ bool AsmParser::enterIncludeFile(const std::string &Filename) {
 /// returns true on failure.
 bool AsmParser::processIncbinFile(const std::string &Filename, int64_t Skip,
                                   const MCExpr *Count, SMLoc Loc) {
+  if (!getProcessIncbinFile())
+    return false;
+
   std::string IncludedFile;
   unsigned NewBuf =
       SrcMgr.AddIncludeFile(Filename, Lexer.getLoc(), IncludedFile);
diff --git a/llvm/lib/Object/ModuleSymbolTable.cpp b/llvm/lib/Object/ModuleSymbolTable.cpp
index 9442becdb7d33..a8b0101187078 100644
--- a/llvm/lib/Object/ModuleSymbolTable.cpp
+++ b/llvm/lib/Object/ModuleSymbolTable.cpp
@@ -129,6 +129,9 @@ initializeRecordStreamer(const Module &M,
   // AsmPrinter::doInitialization()).
   Parser->setAssemblerDialect(InlineAsm::AD_ATT);
 
+  // The .incbin directive cannot introduce new symbols.
+  Parser->setProcessIncbinFile(false);
+
   Parser->setTargetParser(*TAP);
   if (Parser->Run(false))
     return;

>From c1729e7531a9e5444bd3194bf5aac4f279173628 Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda at apple.com>
Date: Mon, 12 Jan 2026 08:19:17 -0800
Subject: [PATCH 2/2] ProcessIncbinFile -> SymbolScanningMode

---
 llvm/include/llvm/MC/MCParser/MCAsmParser.h | 9 ++++++---
 llvm/lib/MC/MCParser/AsmParser.cpp          | 3 ++-
 llvm/lib/Object/ModuleSymbolTable.cpp       | 3 +--
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/MC/MCParser/MCAsmParser.h b/llvm/include/llvm/MC/MCParser/MCAsmParser.h
index 678dc05d29b2a..da5ef08381aed 100644
--- a/llvm/include/llvm/MC/MCParser/MCAsmParser.h
+++ b/llvm/include/llvm/MC/MCParser/MCAsmParser.h
@@ -150,7 +150,11 @@ class LLVM_ABI MCAsmParser {
   bool HadError = false;
 
   bool ShowParsedOperands = false;
-  bool ProcessIncbinFile = true;
+
+  /// Flag tracking whether we're only interested in symbols, which allows us to
+  /// avoid some work (e.g. resolving .incbin directives).
+  // TODO: Adopt this in more places.
+  bool SymbolScanningMode = false;
 
 public:
   MCAsmParser(const MCAsmParser &) = delete;
@@ -177,8 +181,7 @@ class LLVM_ABI MCAsmParser {
   bool getShowParsedOperands() const { return ShowParsedOperands; }
   void setShowParsedOperands(bool Value) { ShowParsedOperands = Value; }
 
-  bool getProcessIncbinFile() const { return ProcessIncbinFile; }
-  void setProcessIncbinFile(bool Value) { ProcessIncbinFile = Value; }
+  void setSymbolScanningMode(bool Value) { SymbolScanningMode = Value; }
 
   /// Run the parser on the input source buffer.
   virtual bool Run(bool NoInitialTextSection, bool NoFinalize = false) = 0;
diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index c9639fcdafe53..e87de484163b1 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -848,7 +848,8 @@ bool AsmParser::enterIncludeFile(const std::string &Filename) {
 /// returns true on failure.
 bool AsmParser::processIncbinFile(const std::string &Filename, int64_t Skip,
                                   const MCExpr *Count, SMLoc Loc) {
-  if (!getProcessIncbinFile())
+  // The .incbin file cannot introduce new symbols.
+  if (SymbolScanningMode)
     return false;
 
   std::string IncludedFile;
diff --git a/llvm/lib/Object/ModuleSymbolTable.cpp b/llvm/lib/Object/ModuleSymbolTable.cpp
index a8b0101187078..ff0bc8b192de7 100644
--- a/llvm/lib/Object/ModuleSymbolTable.cpp
+++ b/llvm/lib/Object/ModuleSymbolTable.cpp
@@ -129,8 +129,7 @@ initializeRecordStreamer(const Module &M,
   // AsmPrinter::doInitialization()).
   Parser->setAssemblerDialect(InlineAsm::AD_ATT);
 
-  // The .incbin directive cannot introduce new symbols.
-  Parser->setProcessIncbinFile(false);
+  Parser->setSymbolScanningMode(true);
 
   Parser->setTargetParser(*TAP);
   if (Parser->Run(false))