[llvm] 7ada6f1 - [AsmParser] Correctly handle .ifeqs nested in other conditional directives (#132713)

[via llvm-commits]

Author: Oliver Stannard
Date: 2025-03-24T14:03:20Z
New Revision: 7ada6f111f133ef2a749c7f395cf337acdaf0f31

URL: https://github.com/llvm/llvm-project/commit/7ada6f111f133ef2a749c7f395cf337acdaf0f31
DIFF: https://github.com/llvm/llvm-project/commit/7ada6f111f133ef2a749c7f395cf337acdaf0f31.diff

LOG: [AsmParser] Correctly handle .ifeqs nested in other conditional directives (#132713)

The parser function used for the .ifeqs and .ifnes directives was
missing the check for whether we are currently in an ignored block of an
outer conditional directive, causing the block to be evaluated when it
should not, for example:

.if 0
  .ifeqs "a", "a"
    // Should not be evaluated, but is
    nop
  .endif
.endif

Added: 
    

Modified: 
    llvm/lib/MC/MCParser/AsmParser.cpp
    llvm/test/MC/AsmParser/ifeqs.s
    llvm/test/MC/AsmParser/ifnes.s

Removed: 
    


################################################################################
diff  --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index c11c01e52fc2e..9448e7b301e28 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -5224,37 +5224,43 @@ bool AsmParser::parseDirectiveIfc(SMLoc DirectiveLoc, bool ExpectEqual) {
 /// parseDirectiveIfeqs
 ///   ::= .ifeqs string1, string2
 bool AsmParser::parseDirectiveIfeqs(SMLoc DirectiveLoc, bool ExpectEqual) {
-  if (Lexer.isNot(AsmToken::String)) {
-    if (ExpectEqual)
-      return TokError("expected string parameter for '.ifeqs' directive");
-    return TokError("expected string parameter for '.ifnes' directive");
-  }
+  TheCondStack.push_back(TheCondState);
+  TheCondState.TheCond = AsmCond::IfCond;
 
-  StringRef String1 = getTok().getStringContents();
-  Lex();
+  if (TheCondState.Ignore) {
+    eatToEndOfStatement();
+  } else {
+    if (Lexer.isNot(AsmToken::String)) {
+      if (ExpectEqual)
+        return TokError("expected string parameter for '.ifeqs' directive");
+      return TokError("expected string parameter for '.ifnes' directive");
+    }
 
-  if (Lexer.isNot(AsmToken::Comma)) {
-    if (ExpectEqual)
+    StringRef String1 = getTok().getStringContents();
+    Lex();
+
+    if (Lexer.isNot(AsmToken::Comma)) {
+      if (ExpectEqual)
+        return TokError(
+            "expected comma after first string for '.ifeqs' directive");
       return TokError(
-          "expected comma after first string for '.ifeqs' directive");
-    return TokError("expected comma after first string for '.ifnes' directive");
-  }
+          "expected comma after first string for '.ifnes' directive");
+    }
 
-  Lex();
+    Lex();
 
-  if (Lexer.isNot(AsmToken::String)) {
-    if (ExpectEqual)
-      return TokError("expected string parameter for '.ifeqs' directive");
-    return TokError("expected string parameter for '.ifnes' directive");
-  }
+    if (Lexer.isNot(AsmToken::String)) {
+      if (ExpectEqual)
+        return TokError("expected string parameter for '.ifeqs' directive");
+      return TokError("expected string parameter for '.ifnes' directive");
+    }
 
-  StringRef String2 = getTok().getStringContents();
-  Lex();
+    StringRef String2 = getTok().getStringContents();
+    Lex();
 
-  TheCondStack.push_back(TheCondState);
-  TheCondState.TheCond = AsmCond::IfCond;
-  TheCondState.CondMet = ExpectEqual == (String1 == String2);
-  TheCondState.Ignore = !TheCondState.CondMet;
+    TheCondState.CondMet = ExpectEqual == (String1 == String2);
+    TheCondState.Ignore = !TheCondState.CondMet;
+  }
 
   return false;
 }

diff  --git a/llvm/test/MC/AsmParser/ifeqs.s b/llvm/test/MC/AsmParser/ifeqs.s
index 05a26a237fcd3..fd5f1a84980a2 100644
--- a/llvm/test/MC/AsmParser/ifeqs.s
+++ b/llvm/test/MC/AsmParser/ifeqs.s
@@ -18,3 +18,14 @@
 // CHECK-NOT: .byte 0
 // CHECK: .byte 1
 
+
+.if 0
+  .ifeqs "alpha", "alpha"
+    .byte 2
+  .else
+    .byte 3
+  .endif
+.endif
+
+// CHECK-NOT: .byte 2
+// CHECK-NOT: .byte 3

diff  --git a/llvm/test/MC/AsmParser/ifnes.s b/llvm/test/MC/AsmParser/ifnes.s
index 7a3cbe0264e1b..bd7dc3b637b21 100644
--- a/llvm/test/MC/AsmParser/ifnes.s
+++ b/llvm/test/MC/AsmParser/ifnes.s
@@ -20,3 +20,13 @@
 # CHECK: .byte 1
 .ifnes "equal", "equal" ; .byte 0 ; .else ; .byte 1 ; .endif
 
+.if 0
+  .ifnes "alpha", "alpha"
+    .byte 2
+  .else
+    .byte 3
+  .endif
+.endif
+
+// CHECK-NOT: .byte 2
+// CHECK-NOT: .byte 3