release/18.x: [X86] Always use 64-bit relocations in no-PIC large code model (#89101) #89124
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@MaskRay What do you think about merging this PR to the release branch? |
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@llvm/pr-subscribers-backend-x86 Author: None (llvmbot) ChangesBackport 6cea7c4 Requested by: @aeubanks Full diff: https://github.com/llvm/llvm-project/pull/89124.diff 2 Files Affected:
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 833f058253d880..553d338b77904a 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2923,11 +2923,10 @@ bool X86DAGToDAGISel::selectAddr(SDNode *Parent, SDValue N, SDValue &Base,
}
bool X86DAGToDAGISel::selectMOV64Imm32(SDValue N, SDValue &Imm) {
- // Cannot use 32 bit constants to reference objects in kernel code model.
- // Cannot use 32 bit constants to reference objects in large PIC mode since
- // GOTOFF is 64 bits.
+ // Cannot use 32 bit constants to reference objects in kernel/large code
+ // model.
if (TM.getCodeModel() == CodeModel::Kernel ||
- (TM.getCodeModel() == CodeModel::Large && TM.isPositionIndependent()))
+ TM.getCodeModel() == CodeModel::Large)
return false;
// In static codegen with small code model, we can get the address of a label
diff --git a/llvm/test/CodeGen/X86/code-model-elf.ll b/llvm/test/CodeGen/X86/code-model-elf.ll
index afcffb3a7adeda..b6634403dc1d05 100644
--- a/llvm/test/CodeGen/X86/code-model-elf.ll
+++ b/llvm/test/CodeGen/X86/code-model-elf.ll
@@ -346,7 +346,7 @@ define dso_local ptr @lea_forced_small_data() #0 {
;
; LARGE-STATIC-LABEL: lea_forced_small_data:
; LARGE-STATIC: # %bb.0:
-; LARGE-STATIC-NEXT: movl $forced_small_data, %eax
+; LARGE-STATIC-NEXT: movabsq $forced_small_data, %rax
; LARGE-STATIC-NEXT: retq
;
; SMALL-PIC-LABEL: lea_forced_small_data:
@@ -399,7 +399,7 @@ define dso_local i32 @load_forced_small_data() #0 {
;
; LARGE-STATIC-LABEL: load_forced_small_data:
; LARGE-STATIC: # %bb.0:
-; LARGE-STATIC-NEXT: movl $forced_small_data+8, %eax
+; LARGE-STATIC-NEXT: movabsq $forced_small_data+8, %rax
; LARGE-STATIC-NEXT: movl (%rax), %eax
; LARGE-STATIC-NEXT: retq
;
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MaskRay
approved these changes
Apr 18, 2024
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@tstellar looks like the version check is failing, how can I get this merged? |
…89101) This matches other types of relocations, e.g. to constant pool. And makes things more consistent with PIC large code model. Some users of the large code model may not place small data in the lower 2GB of the address space (e.g. ClangBuiltLinux/linux#2016), so just unconditionally use 64-bit relocations in the large code model. So now functions in a section not marked large will use 64-bit relocations to reference everything when using the large code model. This also fixes some lldb tests broken by llvm#88172 (https://lab.llvm.org/buildbot/#/builders/68/builds/72458). (cherry picked from commit 6cea7c4)
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Hi @aeubanks (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
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this is mostly a fix to revert back to previous behavior in certain cases, so probably not worth a release note |
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Backport 6cea7c4
Requested by: @aeubanks