0d471b3f64
This patch fixes https://github.com/llvm/llvm-project/issues/17204. If a base pointer is used in a function, and it is clobbered by an instruction (typically an inline asm), current register allocator can't handle this situation, so BP becomes garbage after those instructions. It can also occur to FP in theory. We can spill and reload FP/BP registers around those instructions. But normal spill/reload instructions also use FP/BP, so we can't spill them into normal spill slots, instead we spill them into the top of stack by using SP register.
77 lines
2.3 KiB
LLVM
77 lines
2.3 KiB
LLVM
; RUN: llc -O2 --relocation-model=pic -mtriple=i386-unknown-linux-gnu < %s 2>&1 | FileCheck %s
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; List the source code:
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; // clang -m32 -fasm-blocks -S t.c -O2 -fpic -emit-llvm
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; int GV = 17;
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;
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; extern unsigned int extern_func();
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; static unsigned int static_func() __attribute__((noinline));
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; static unsigned int static_func() {
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; return GV++;
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; }
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;
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; void func() {
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; static_func();
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; __asm {
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; call static_func
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; call extern_func
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; jmp extern_func
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; shr eax, 0
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; shr ebx, 0
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; shr ecx, 0
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; shr edx, 0
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; shr edi, 0
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; shr esi, 0
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; shr ebp, 0
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; shr esp, 0
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; }
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; }
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@GV = local_unnamed_addr global i32 17, align 4
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define void @func() local_unnamed_addr #0 {
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; CHECK-LABEL: func:
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; CHECK: calll .L0$pb
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; CHECK-NEXT: .L0$pb:
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; CHECK-NEXT: popl %ebx
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; CHECK-NEXT: .Ltmp0:
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; CHECK-NEXT: addl $_GLOBAL_OFFSET_TABLE_+(.Ltmp0-.L0$pb), %ebx
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; CHECK-NEXT: calll static_func
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; CHECK-NEXT: pushl %ebp
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; CHECK-NEXT: subl $12, %esp
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; CHECK-NEXT: #APP
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; CHECK-EMPTY:
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; CHECK-NEXT: calll static_func
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; CHECK-NEXT: calll extern_func@PLT
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; CHECK-NEXT: jmp extern_func@PLT
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; CHECK-NEXT: shrl $0, %eax
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; CHECK-NEXT: shrl $0, %ebx
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; CHECK-NEXT: shrl $0, %ecx
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; CHECK-NEXT: shrl $0, %edx
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; CHECK-NEXT: shrl $0, %edi
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; CHECK-NEXT: shrl $0, %esi
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; CHECK-NEXT: shrl $0, %ebp
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; CHECK-NEXT: shrl $0, %esp
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; CHECK-EMPTY:
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; CHECK-NEXT: #NO_APP
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; CHECK-NEXT: addl $12, %esp
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; CHECK-NEXT: popl %ebp
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entry:
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%call = tail call i32 @static_func()
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;; We test call, CALL, and jmp.
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tail call void asm sideeffect inteldialect "call ${0:P}\0A\09CALL ${1:P}\0A\09jmp ${1:P}\0A\09shr eax, $$0\0A\09shr ebx, $$0\0A\09shr ecx, $$0\0A\09shr edx, $$0\0A\09shr edi, $$0\0A\09shr esi, $$0\0A\09shr ebp, $$0\0A\09shr esp, $$0", "*m,*m,~{eax},~{ebp},~{ebx},~{ecx},~{edi},~{edx},~{flags},~{esi},~{esp},~{dirflag},~{fpsr},~{flags}"(ptr nonnull elementtype(i32 (...)) @static_func, ptr nonnull elementtype(i32 (...)) @extern_func) #0
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ret void
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}
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declare i32 @extern_func(...) #0
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define internal i32 @static_func() #0 {
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entry:
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%0 = load i32, ptr @GV, align 4
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%inc = add nsw i32 %0, 1
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store i32 %inc, ptr @GV, align 4
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ret i32 %0
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}
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attributes #0 = { nounwind }
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