[PATCH] D80763: [X86] Fix a nullptr defrence in X86Subtarget::classifyLocalReference when compiling with -mcmodel=medium -fpic and using a constant pool

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: efriedma, rnk, echristo.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

LowerConstantPool passes a nullptr into classifyLocalReference. The medium code model handling for PIC will try to deference it using isa. This patch switches to isa_and_nonnull.


https://reviews.llvm.org/D80763

Files:
  llvm/lib/Target/X86/X86Subtarget.cpp
  llvm/test/CodeGen/X86/code-model-elf.ll


Index: llvm/test/CodeGen/X86/code-model-elf.ll
===================================================================
--- llvm/test/CodeGen/X86/code-model-elf.ll
+++ llvm/test/CodeGen/X86/code-model-elf.ll
@@ -439,6 +439,49 @@
   ret i32 %1
 }
 
+define dso_local float @load_constant_pool(float %x) #0 {
+; SMALL-STATIC-LABEL: load_constant_pool:
+; SMALL-STATIC:       # %bb.0:
+; SMALL-STATIC-NEXT:    addss {{\.LCPI.*}}(%rip), %xmm0
+; SMALL-STATIC-NEXT:    retq
+;
+; MEDIUM-STATIC-LABEL: load_constant_pool:
+; MEDIUM-STATIC:       # %bb.0:
+; MEDIUM-STATIC-NEXT:    movabsq ${{\.LCPI.*}}, %rax
+; MEDIUM-STATIC-NEXT:    addss (%rax), %xmm0
+; MEDIUM-STATIC-NEXT:    retq
+;
+; LARGE-STATIC-LABEL: load_constant_pool:
+; LARGE-STATIC:       # %bb.0:
+; LARGE-STATIC-NEXT:    movabsq ${{\.LCPI.*}}, %rax
+; LARGE-STATIC-NEXT:    addss (%rax), %xmm0
+; LARGE-STATIC-NEXT:    retq
+;
+; SMALL-PIC-LABEL: load_constant_pool:
+; SMALL-PIC:       # %bb.0:
+; SMALL-PIC-NEXT:    addss {{\.LCPI.*}}(%rip), %xmm0
+; SMALL-PIC-NEXT:    retq
+;
+; MEDIUM-PIC-LABEL: load_constant_pool:
+; MEDIUM-PIC:       # %bb.0:
+; MEDIUM-PIC-NEXT:    leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
+; MEDIUM-PIC-NEXT:    movabsq ${{\.LCPI.*}}@GOTOFF, %rcx
+; MEDIUM-PIC-NEXT:    addss (%rax,%rcx), %xmm0
+; MEDIUM-PIC-NEXT:    retq
+;
+; LARGE-PIC-LABEL: load_constant_pool:
+; LARGE-PIC:       # %bb.0:
+; LARGE-PIC-NEXT:  .L11$pb:
+; LARGE-PIC-NEXT:    leaq .L11$pb(%rip), %rax
+; LARGE-PIC-NEXT:    movabsq $_GLOBAL_OFFSET_TABLE_-.L11$pb, %rcx
+; LARGE-PIC-NEXT:    addq %rax, %rcx
+; LARGE-PIC-NEXT:    movabsq ${{\.LCPI.*}}@GOTOFF, %rax
+; LARGE-PIC-NEXT:    addss (%rcx,%rax), %xmm0
+; LARGE-PIC-NEXT:    retq
+  %a = fadd float %x, 1.0
+  ret float %a
+}
+
 attributes #0 = { noinline nounwind uwtable }
 
 !llvm.module.flags = !{!0, !1, !2}
Index: llvm/lib/Target/X86/X86Subtarget.cpp
===================================================================
--- llvm/lib/Target/X86/X86Subtarget.cpp
+++ llvm/lib/Target/X86/X86Subtarget.cpp
@@ -88,7 +88,7 @@
 
       // Medium is a hybrid: RIP-rel for code, GOTOFF for DSO local data.
       case CodeModel::Medium:
-        if (isa<Function>(GV))
+        if (isa_and_nonnull<Function>(GV))
           return X86II::MO_NO_FLAG; // All code is RIP-relative
         return X86II::MO_GOTOFF;    // Local symbols use GOTOFF.
       }


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