[PATCH] D122236: [RISCV] Fix crash for initial section alignment with .option norvc

[Luís Marques via Phabricator via llvm-commits]

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The existing code wasn't getting the subtarget info from the fragment, so the current status of RVC would be ignored. This would cause a crash for the new test case when the target then reported it couldn't write the requested number of code alignment bytes.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D122236

Files:
  llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
  llvm/test/MC/RISCV/align.s


Index: llvm/test/MC/RISCV/align.s
===================================================================
--- llvm/test/MC/RISCV/align.s
+++ llvm/test/MC/RISCV/align.s
@@ -112,3 +112,11 @@
 # C-EXT-RELAX-RELOC-NOT: R_RISCV_ALIGN
 data2:
 	.word 9
+# Check that the initial alignment is properly handled when using .option to
+# disable the C extension. This used to crash.
+# C-EXT-RELAX-INST:      <.text2>:
+# C-EXT-RELAX-INST-NEXT: add a0, a0, a1
+	.section .text2, "x"
+	.option norvc
+	.balign 4
+	add	a0, a0, a1
Index: llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
===================================================================
--- llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
+++ llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
@@ -583,10 +583,11 @@
 bool RISCVAsmBackend::shouldInsertExtraNopBytesForCodeAlign(
     const MCAlignFragment &AF, unsigned &Size) {
   // Calculate Nops Size only when linker relaxation enabled.
-  if (!STI.getFeatureBits()[RISCV::FeatureRelax])
+  const MCSubtargetInfo *STI = AF.getSubtargetInfo();
+  if (!STI->getFeatureBits()[RISCV::FeatureRelax])
     return false;
 
-  bool HasStdExtC = STI.getFeatureBits()[RISCV::FeatureStdExtC];
+  bool HasStdExtC = STI->getFeatureBits()[RISCV::FeatureStdExtC];
   unsigned MinNopLen = HasStdExtC ? 2 : 4;
 
   if (AF.getAlignment() <= MinNopLen) {
@@ -606,7 +607,8 @@
                                                     const MCAsmLayout &Layout,
                                                     MCAlignFragment &AF) {
   // Insert the fixup only when linker relaxation enabled.
-  if (!STI.getFeatureBits()[RISCV::FeatureRelax])
+  const MCSubtargetInfo *STI = AF.getSubtargetInfo();
+  if (!STI->getFeatureBits()[RISCV::FeatureRelax])
     return false;
 
   // Calculate total Nops we need to insert. If there are none to insert


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