[llvm] Add support for the .base64 directive (fixes #165499) (PR #165549)

Ben Kallus via llvm-commits llvm-commits at lists.llvm.org
Tue Nov 4 06:33:25 PST 2025


https://github.com/kenballus updated https://github.com/llvm/llvm-project/pull/165549

>From 4ca5466ad319ade27c44903ab25f38e81efb5076 Mon Sep 17 00:00:00 2001
From: Ben Kallus <benjamin.p.kallus.gr at dartmouth.edu>
Date: Fri, 31 Oct 2025 09:06:05 -0400
Subject: [PATCH 1/2] MC/AsmParser: Add .base64 directive

---
 llvm/lib/MC/MCParser/AsmParser.cpp        | 25 +++++++++++++++++++++++
 llvm/test/MC/AsmParser/directive_base64.s | 12 +++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 llvm/test/MC/AsmParser/directive_base64.s

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index dd1bc2be5feb4..357b114f0b1e3 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -46,6 +46,7 @@
 #include "llvm/MC/MCSymbolMachO.h"
 #include "llvm/MC/MCTargetOptions.h"
 #include "llvm/MC/MCValue.h"
+#include "llvm/Support/Base64.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -530,6 +531,7 @@ class AsmParser : public MCAsmParser {
     DK_LTO_SET_CONDITIONAL,
     DK_CFI_MTE_TAGGED_FRAME,
     DK_MEMTAG,
+    DK_BASE64,
     DK_END
   };
 
@@ -552,6 +554,7 @@ class AsmParser : public MCAsmParser {
 
   // ".ascii", ".asciz", ".string"
   bool parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated);
+  bool parseDirectiveBase64();                  // ".base64"
   bool parseDirectiveReloc(SMLoc DirectiveLoc); // ".reloc"
   bool parseDirectiveValue(StringRef IDVal,
                            unsigned Size);       // ".byte", ".long", ...
@@ -1953,6 +1956,8 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info,
     case DK_ASCIZ:
     case DK_STRING:
       return parseDirectiveAscii(IDVal, true);
+    case DK_BASE64:
+      return parseDirectiveBase64();
     case DK_BYTE:
     case DK_DC_B:
       return parseDirectiveValue(IDVal, 1);
@@ -3076,6 +3081,25 @@ bool AsmParser::parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated) {
   return parseMany(parseOp);
 }
 
+/// parseDirectiveBase64:
+//    ::= .base64 "string"
+bool AsmParser::parseDirectiveBase64() {
+  if (checkForValidSection() ||
+      check(getTok().isNot(AsmToken::String), "expected string")) {
+    return true;
+  }
+
+  std::vector<char> Decoded;
+  std::string const str = getTok().getStringContents().str();
+  if (str.empty() || decodeBase64(str, Decoded)) {
+    return true;
+  }
+
+  getStreamer().emitBytes(std::string(Decoded.begin(), Decoded.end()));
+  Lex();
+  return false;
+}
+
 /// parseDirectiveReloc
 ///  ::= .reloc expression , identifier [ , expression ]
 bool AsmParser::parseDirectiveReloc(SMLoc DirectiveLoc) {
@@ -5345,6 +5369,7 @@ void AsmParser::initializeDirectiveKindMap() {
   DirectiveKindMap[".asciz"] = DK_ASCIZ;
   DirectiveKindMap[".string"] = DK_STRING;
   DirectiveKindMap[".byte"] = DK_BYTE;
+  DirectiveKindMap[".base64"] = DK_BASE64;
   DirectiveKindMap[".short"] = DK_SHORT;
   DirectiveKindMap[".value"] = DK_VALUE;
   DirectiveKindMap[".2byte"] = DK_2BYTE;
diff --git a/llvm/test/MC/AsmParser/directive_base64.s b/llvm/test/MC/AsmParser/directive_base64.s
new file mode 100644
index 0000000000000..947895caa171f
--- /dev/null
+++ b/llvm/test/MC/AsmParser/directive_base64.s
@@ -0,0 +1,12 @@
+# RUN: llvm-mc -triple i386-unknown-unknown %s | FileCheck %s
+
+        .data
+# CHECK: TEST0:
+# CHECK: .byte 0
+TEST0:
+        .base64 "AA=="
+
+# CHECK: TEST1:
+# CHECK: .ascii "abcxyz"
+TEST1:
+        .base64 "YWJjeHl6"

>From 0df7acd3b1f68bafb72bd2e2f12031960a9ff945 Mon Sep 17 00:00:00 2001
From: Ben Kallus <benjamin.p.kallus.gr at dartmouth.edu>
Date: Tue, 4 Nov 2025 09:33:07 -0500
Subject: [PATCH 2/2] Make base64 directive take multiple comma-separated
 operands and improve tests.

---
 llvm/lib/MC/MCParser/AsmParser.cpp        | 38 +++++++++++++++--------
 llvm/test/MC/AsmParser/directive_base64.s | 33 +++++++++++++++++---
 2 files changed, 54 insertions(+), 17 deletions(-)

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 439dcbcddb456..c9cce7d69cc01 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -3080,22 +3080,34 @@ bool AsmParser::parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated) {
 }
 
 /// parseDirectiveBase64:
-//    ::= .base64 "string"
+//    ::= .base64 "string" (, "string" )*
 bool AsmParser::parseDirectiveBase64() {
-  if (checkForValidSection() ||
-      check(getTok().isNot(AsmToken::String), "expected string")) {
-    return true;
-  }
+  auto parseOp = [&]() -> bool {
+    if (checkForValidSection())
+      return true;
 
-  std::vector<char> Decoded;
-  std::string const str = getTok().getStringContents().str();
-  if (str.empty() || decodeBase64(str, Decoded)) {
-    return true;
-  }
+    if (getTok().isNot(AsmToken::String)) {
+      return true;
+    }
 
-  getStreamer().emitBytes(std::string(Decoded.begin(), Decoded.end()));
-  Lex();
-  return false;
+    std::vector<char> Decoded;
+    std::string const str = getTok().getStringContents().str();
+    if (check(str.empty(), "expected nonempty string")) {
+      return true;
+    }
+
+    llvm::Error e = decodeBase64(str, Decoded);
+    if (e) {
+      consumeError(std::move(e));
+      return Error(Lexer.getLoc(), "failed to base64 decode string data");
+    }
+
+    getStreamer().emitBytes(std::string(Decoded.begin(), Decoded.end()));
+    Lex();
+    return false;
+  };
+
+  return check(parseMany(parseOp), "expected string");
 }
 
 /// parseDirectiveReloc
diff --git a/llvm/test/MC/AsmParser/directive_base64.s b/llvm/test/MC/AsmParser/directive_base64.s
index 947895caa171f..46a477eef51dc 100644
--- a/llvm/test/MC/AsmParser/directive_base64.s
+++ b/llvm/test/MC/AsmParser/directive_base64.s
@@ -1,12 +1,37 @@
 # RUN: llvm-mc -triple i386-unknown-unknown %s | FileCheck %s
+# RUN: not llvm-mc -triple i386-unknown-unknown -defsym=ERR=1 -o /dev/null %s 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR
 
         .data
-# CHECK: TEST0:
-# CHECK: .byte 0
+# CHECK-LABEL: TEST0:
+# CHECK-NEXT: .byte 0
 TEST0:
         .base64 "AA=="
 
-# CHECK: TEST1:
-# CHECK: .ascii "abcxyz"
+# CHECK-LABEL: TEST1:
+# CHECK-NEXT: .ascii "abcxyz"
 TEST1:
         .base64 "YWJjeHl6"
+
+# CHECK-LABEL: TEST2:
+# CHECK-NEXT: .byte 1
+# CHECK-NEXT: .byte 2
+TEST2:
+        .base64 "AQ=="
+        .base64 "Ag=="
+
+# CHECK-LABEL: TEST3:
+# CHECK-NEXT: .byte 1
+# CHECK-NEXT: .byte 2
+TEST3:
+        .base64 "AQ==", "Ag=="
+
+.ifdef ERR
+# CHECK-ERROR: [[#@LINE+1]]:17: error: expected string
+        .base64 not-a-string
+
+# CHECK-ERROR: [[#@LINE+1]]:17: error: failed to base64 decode string data
+        .base64 "AA"
+
+# CHECK-ERROR: [[#@LINE+1]]:17: error: expected nonempty string
+        .base64 ""
+.endif



More information about the llvm-commits mailing list