mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-24 06:30:19 +00:00
8f832fce3b
This was motivated by a bug which caused code like this to be
miscompiled:
declare void @take_ptr(i8*)
define void @test() {
%addr1.32 = alloca i8
%addr2.32 = alloca i32, i32 1028
call void @take_ptr(i8* %addr1)
ret void
}
This was emitting the following assembly to get the value of %addr1:
add r0, sp, #1020
add r0, r0, #8
However, "add r0, r0, #8" is not a valid Thumb1 instruction, and this
could not be assembled. The generated object file contained this,
resulting in r0 holding SP+8 rather tha SP+1028:
add r0, sp, #1020
add r0, sp, #8
This function looked like it could have caused miscompilations for
other combinations of registers and offsets (though I don't think it is
currently called with these), and the heuristic it used did not match
the emitted code in all cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222125 91177308-0d34-0410-b5e6-96231b3b80d8
144 lines
3.3 KiB
LLVM
144 lines
3.3 KiB
LLVM
; RUN: llc < %s -mtriple=thumbv6-apple-darwin | FileCheck %s
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; RUN: llc < %s -mtriple=thumbv6-apple-darwin -regalloc=basic | FileCheck %s
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; RUN: llc < %s -o %t -filetype=obj -mtriple=thumbv6-apple-darwin
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; RUN: llvm-objdump -triple=thumbv6-apple-darwin -d %t | FileCheck %s
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@__bar = external hidden global i8*
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@__baz = external hidden global i8*
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; rdar://8819685
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define i8* @_foo() {
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entry:
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; CHECK-LABEL: foo:
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%size = alloca i32, align 4
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%0 = load i8** @__bar, align 4
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%1 = icmp eq i8* %0, null
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br i1 %1, label %bb1, label %bb3
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; CHECK: bne
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bb1:
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store i32 1026, i32* %size, align 4
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%2 = alloca [1026 x i8], align 1
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; CHECK: mov [[R0:r[0-9]+]], sp
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; CHECK: adds {{r[0-9]+}}, [[R0]], {{r[0-9]+}}
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%3 = getelementptr inbounds [1026 x i8]* %2, i32 0, i32 0
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%4 = call i32 @_called_func(i8* %3, i32* %size) nounwind
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%5 = icmp eq i32 %4, 0
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br i1 %5, label %bb2, label %bb3
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bb2:
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%6 = call i8* @strdup(i8* %3) nounwind
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store i8* %6, i8** @__baz, align 4
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br label %bb3
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bb3:
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%.0 = phi i8* [ %0, %entry ], [ %6, %bb2 ], [ %3, %bb1 ]
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; CHECK: subs r4, #5
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; CHECK-NEXT: mov sp, r4
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; CHECK-NEXT: pop {r4, r5, r6, r7, pc}
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ret i8* %.0
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}
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declare noalias i8* @strdup(i8* nocapture) nounwind
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declare i32 @_called_func(i8*, i32*) nounwind
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; Variable ending up at unaligned offset from sp (i.e. not a multiple of 4)
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define void @test_local_var_addr() {
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; CHECK-LABEL: test_local_var_addr:
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%addr1 = alloca i8
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%addr2 = alloca i8
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; CHECK: mov r0, sp
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; CHECK: adds r0, #{{[0-9]+}}
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; CHECK: blx
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call void @take_ptr(i8* %addr1)
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; CHECK: mov r0, sp
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; CHECK: adds r0, #{{[0-9]+}}
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; CHECK: blx
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call void @take_ptr(i8* %addr2)
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ret void
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}
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; Simple variable ending up *at* sp.
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define void @test_simple_var() {
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; CHECK-LABEL: test_simple_var:
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%addr32 = alloca i32
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%addr8 = bitcast i32* %addr32 to i8*
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; CHECK: mov r0, sp
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; CHECK-NOT: adds r0
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; CHECK: blx
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call void @take_ptr(i8* %addr8)
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ret void
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}
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; Simple variable ending up at aligned offset from sp.
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define void @test_local_var_addr_aligned() {
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; CHECK-LABEL: test_local_var_addr_aligned:
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%addr1.32 = alloca i32
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%addr1 = bitcast i32* %addr1.32 to i8*
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%addr2.32 = alloca i32
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%addr2 = bitcast i32* %addr2.32 to i8*
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; CHECK: add r0, sp, #{{[0-9]+}}
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; CHECK: blx
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call void @take_ptr(i8* %addr1)
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; CHECK: mov r0, sp
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; CHECK-NOT: add r0
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; CHECK: blx
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call void @take_ptr(i8* %addr2)
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ret void
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}
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; Simple variable ending up at aligned offset from sp.
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define void @test_local_var_big_offset() {
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; CHECK-LABEL: test_local_var_big_offset:
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%addr1.32 = alloca i32, i32 257
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%addr1 = bitcast i32* %addr1.32 to i8*
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%addr2.32 = alloca i32, i32 257
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; CHECK: add [[RTMP:r[0-9]+]], sp, #1020
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; CHECK: adds [[RTMP]], #8
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; CHECK: blx
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call void @take_ptr(i8* %addr1)
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ret void
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}
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; Max range addressable with tADDrSPi
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define void @test_local_var_offset_1020() {
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; CHECK-LABEL: test_local_var_offset_1020
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%addr1 = alloca i8, i32 4
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%addr2 = alloca i8, i32 1020
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; CHECK: add r0, sp, #1020
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; CHECK-NEXT: blx
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call void @take_ptr(i8* %addr1)
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ret void
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}
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; Max range addressable with tADDrSPi + tADDi8
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define void @test_local_var_offset_1275() {
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; CHECK-LABEL: test_local_var_offset_1275
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%addr1 = alloca i8, i32 1
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%addr2 = alloca i8, i32 1275
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; CHECK: add r0, sp, #1020
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; CHECK: adds r0, #255
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; CHECK-NEXT: blx
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call void @take_ptr(i8* %addr1)
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ret void
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}
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declare void @take_ptr(i8*)
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