[PATCH] D101975: [AsmParser][ARM] Make .thumb_func imply .thumb

[LemonBoy via Phabricator via llvm-commits]

LemonBoy created this revision.
LemonBoy added reviewers: MaskRay, t.p.northover, lenary, nickdesaulniers.
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GNU as documentation states that a `.thumb_func` directive implies `.thumb`, teach the asm parser to switch mode whenever it's encountered. On the other hand the labeled form, exclusive to Apple's toolchain, doesn't switch mode at all.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D101975

Files:
  llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
  llvm/test/MC/ARM/thumb_func-implies-thumb.s


Index: llvm/test/MC/ARM/thumb_func-implies-thumb.s
===================================================================
--- /dev/null
+++ llvm/test/MC/ARM/thumb_func-implies-thumb.s
@@ -0,0 +1,20 @@
+@ RUN: llvm-mc -triple=armv7-darwin- -show-encoding < %s | FileCheck %s
+.syntax unified
+
+.text
+
+.arm
+@ Ensure the plain form switches mode.
+.thumb_func
+@ CHECK: .code 16
+@ CHECK-LABEL: foo
+foo:
+    bx lr
+
+.arm
+@ Ensure the labeled form doesn't switch mode.
+.thumb_func bar
+@ CHECK-NOT: .code 16
+@ CHECK-LABEL: bar
+bar:
+    bx lr
Index: llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
===================================================================
--- llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -11167,6 +11167,12 @@
                  "unexpected token in '.thumb_func' directive"))
     return true;
 
+  // .thumb_func implies .thumb
+  if (!isThumb())
+    SwitchMode();
+
+  getParser().getStreamer().emitAssemblerFlag(MCAF_Code16);
+
   NextSymbolIsThumb = true;
   return false;
 }


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