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llvm-project/llvm/test/Transforms/RelLookupTableConverter/X86/relative_lookup_table.ll

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[Passes] Add relative lookup table converter pass Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in: https://bugs.llvm.org/show_bug.cgi?id=45244 This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly. Differential Revision: https://reviews.llvm.org/D94355
2020-12-30 05:32:13 +08:00
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; REQUIRES: x86-registered-target
; RUN: opt < %s -passes=rel-lookup-table-converter -relocation-model=pic -S | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@.str = private unnamed_addr constant [5 x i8] c"zero\00", align 1
@.str.1 = private unnamed_addr constant [4 x i8] c"one\00", align 1
@.str.2 = private unnamed_addr constant [4 x i8] c"two\00", align 1
@.str.3 = private unnamed_addr constant [8 x i8] c"default\00", align 1
@.str.4 = private unnamed_addr constant [6 x i8] c"three\00", align 1
@.str.5 = private unnamed_addr constant [5 x i8] c"str1\00", align 1
@.str.6 = private unnamed_addr constant [5 x i8] c"str2\00", align 1
@.str.7 = private unnamed_addr constant [12 x i8] c"singlevalue\00", align 1
[Passes] Fix relative lookup table converter pass This patch fixes the relative table converter pass for the lookup table accesses that are resulted in an instruction sequence, where gep is not immediately followed by a load, such as gep being hoisted outside the loop or another instruction is inserted in between them. The fix inserts the call to load.relative.instrinsic in the original place of load instead of gep. Issue is reported by FreeBSD via https://bugs.freebsd.org/259921. Differential Revision: https://reviews.llvm.org/D115571
2021-12-11 11:14:48 +08:00
@.str.8 = private unnamed_addr constant [2 x i8] c"a\00", align 1
@.str.9 = private unnamed_addr constant [2 x i8] c"b\00", align 1
@.str.10 = private unnamed_addr constant [2 x i8] c"c\00", align 1
[Passes] Add relative lookup table converter pass Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in: https://bugs.llvm.org/show_bug.cgi?id=45244 This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly. Differential Revision: https://reviews.llvm.org/D94355
2020-12-30 05:32:13 +08:00
@a1 = external global i32, align 4
@b1 = external global i32, align 4
@c1 = external global i32, align 4
@d1 = external global i32, align 4
@a2 = internal constant i32 0, align 4
@b2 = internal constant i32 0, align 4
@c2 = internal constant i32 0, align 4
@d2 = internal constant i32 0, align 4
@switch.table.external_linkage = private unnamed_addr constant [3 x i32*] [i32* @a1, i32* @b1, i32* @c1], align 8
@switch.table.internal_linkage = private unnamed_addr constant [3 x i32*] [i32* @a2, i32* @b2, i32* @c2], align 8
@switch.table.string_table = private unnamed_addr constant [3 x i8*]
[
i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0),
i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0),
i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0)
], align 8
@switch.table.string_table_holes = private unnamed_addr constant [4 x i8*]
[
i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0),
i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0),
i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0),
i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str.4, i64 0, i64 0)
], align 8
@switch.table.single_value = private unnamed_addr constant [3 x i8*]
[
i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0),
i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0),
i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0)
], align 8
@user_defined_lookup_table.table = internal unnamed_addr constant [3 x i8*]
[
i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i32 0, i32 0),
i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i32 0, i32 0),
i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i32 0, i32 0)
], align 16
[Passes] Fix relative lookup table converter pass This patch fixes the relative table converter pass for the lookup table accesses that are resulted in an instruction sequence, where gep is not immediately followed by a load, such as gep being hoisted outside the loop or another instruction is inserted in between them. The fix inserts the call to load.relative.instrinsic in the original place of load instead of gep. Issue is reported by FreeBSD via https://bugs.freebsd.org/259921. Differential Revision: https://reviews.llvm.org/D115571
2021-12-11 11:14:48 +08:00
@table = internal constant [2 x i8*] [
i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.8, i32 0, i32 0),
i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.9, i32 0, i32 0)
], align 16
@table2 = internal constant [2 x i8*] [
i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.8, i32 0, i32 0),
i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.9, i32 0, i32 0)
], align 16
[Passes] Add relative lookup table converter pass Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in: https://bugs.llvm.org/show_bug.cgi?id=45244 This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly. Differential Revision: https://reviews.llvm.org/D94355
2020-12-30 05:32:13 +08:00
; Lookup table check for integer pointers that have external linkage
; CHECK: @switch.table.external_linkage = private unnamed_addr constant [3 x i32*] [i32* @a1, i32* @b1, i32* @c1], align
; Lookup table check for integer pointers that have internal linkage
; CHECK: @reltable.internal_linkage = private unnamed_addr constant [3 x i32]
; CHECK-SAME: [
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint (i32* @a2 to i64), i64 ptrtoint ([3 x i32]* @reltable.internal_linkage to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint (i32* @b2 to i64), i64 ptrtoint ([3 x i32]* @reltable.internal_linkage to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint (i32* @c2 to i64), i64 ptrtoint ([3 x i32]* @reltable.internal_linkage to i64)) to i32)
; CHECK-SAME: ], align 4
; Relative switch lookup table for strings
; CHECK: @reltable.string_table = private unnamed_addr constant [3 x i32]
; CHECK-SAME: [
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str to i64), i64 ptrtoint ([3 x i32]* @reltable.string_table to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.1 to i64), i64 ptrtoint ([3 x i32]* @reltable.string_table to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.2 to i64), i64 ptrtoint ([3 x i32]* @reltable.string_table to i64)) to i32)
; CHECK-SAME: ], align 4
; Relative switch lookup table for strings with holes, where holes are filled with relative offset to default values
; CHECK: @reltable.string_table_holes = private unnamed_addr constant [4 x i32]
; CHECK-SAME: [
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str to i64), i64 ptrtoint ([4 x i32]* @reltable.string_table_holes to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.3 to i64), i64 ptrtoint ([4 x i32]* @reltable.string_table_holes to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.2 to i64), i64 ptrtoint ([4 x i32]* @reltable.string_table_holes to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.4 to i64), i64 ptrtoint ([4 x i32]* @reltable.string_table_holes to i64)) to i32)
; CHECK-SAME: ], align 4
; Single value check
; CHECK: @reltable.single_value = private unnamed_addr constant [3 x i32]
; CHECK-SAME: [
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str to i64), i64 ptrtoint ([3 x i32]* @reltable.single_value to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.1 to i64), i64 ptrtoint ([3 x i32]* @reltable.single_value to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.2 to i64), i64 ptrtoint ([3 x i32]* @reltable.single_value to i64)) to i32)
; CHECK-SAME: ], align 4
;
[Passes] Fix relative lookup table converter pass This patch fixes the relative table converter pass for the lookup table accesses that are resulted in an instruction sequence, where gep is not immediately followed by a load, such as gep being hoisted outside the loop or another instruction is inserted in between them. The fix inserts the call to load.relative.instrinsic in the original place of load instead of gep. Issue is reported by FreeBSD via https://bugs.freebsd.org/259921. Differential Revision: https://reviews.llvm.org/D115571
2021-12-11 11:14:48 +08:00
; Relative lookup table for the loop hoist check test
; CHECK: @reltable.loop_hoist = internal unnamed_addr constant [2 x i32]
; CHECK-SAME: [
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([2 x i8]* @.str.8 to i64), i64 ptrtoint ([2 x i32]* @reltable.loop_hoist to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([2 x i8]* @.str.9 to i64), i64 ptrtoint ([2 x i32]* @reltable.loop_hoist to i64)) to i32)
; CHECK-SAME: ], align 4
; Relative look up table for the test where gep is not immediately followed by a load check
; CHECK: @reltable.gep_is_not_imm_followed_by_load = internal unnamed_addr constant [2 x i32]
; CHECK-SAME: [
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([2 x i8]* @.str.8 to i64), i64 ptrtoint ([2 x i32]* @reltable.gep_is_not_imm_followed_by_load to i64)) to i32),
; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint ([2 x i8]* @.str.9 to i64), i64 ptrtoint ([2 x i32]* @reltable.gep_is_not_imm_followed_by_load to i64)) to i32)
; CHECK-SAME: ], align 4
[Passes] Add relative lookup table converter pass Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in: https://bugs.llvm.org/show_bug.cgi?id=45244 This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly. Differential Revision: https://reviews.llvm.org/D94355
2020-12-30 05:32:13 +08:00
; Lookup table check for integer pointers that have external linkage
define i32* @external_linkage(i32 %cond) {
; CHECK-LABEL: @external_linkage(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp ult i32 [[COND:%.*]], 3
; CHECK-NEXT: br i1 [[TMP0]], label [[SWITCH_LOOKUP:%.*]], label [[RETURN:%.*]]
; CHECK: switch.lookup:
; CHECK-NEXT: [[SWITCH_GEP:%.*]] = getelementptr inbounds [3 x i32*], [3 x i32*]* @switch.table.external_linkage, i32 0, i32 [[COND:%.*]]
; CHECK-NEXT: [[SWITCH_LOAD:%.*]] = load i32*, i32** [[SWITCH_GEP]], align 8
; CHECK-NEXT: ret i32* [[SWITCH_LOAD]]
; CHECK: return:
; CHECK-NEXT: ret i32* @d1
;
entry:
%0 = icmp ult i32 %cond, 3
br i1 %0, label %switch.lookup, label %return
switch.lookup: ; preds = %entry
%switch.gep = getelementptr inbounds [3 x i32*], [3 x i32*]* @switch.table.external_linkage, i32 0, i32 %cond
%switch.load = load i32*, i32** %switch.gep, align 8
ret i32* %switch.load
return: ; preds = %entry
ret i32* @d1
}
; Relative switch lookup table for integer pointers that have internal linkage
define i32* @internal_linkage(i32 %cond) {
; CHECK-LABEL: @internal_linkage(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp ult i32 [[COND:%.*]], 3
; CHECK-NEXT: br i1 [[TMP0]], label [[SWITCH_LOOKUP:%.*]], label [[RETURN:%.*]]
; CHECK: switch.lookup:
; CHECK-NEXT: [[RELTABLE_SHIFT:%.*]] = shl i32 %cond, 2
; CHECK-NEXT: [[RELTABLE_INTRINSIC:%.*]] = call i8* @llvm.load.relative.i32(i8* bitcast ([3 x i32]* @reltable.internal_linkage to i8*), i32 [[RELTABLE_SHIFT]])
; CHECK-NEXT: [[BIT_CAST:%.*]] = bitcast i8* [[RELTABLE_INTRINSIC]] to i32*
; CHECK-NEXT: ret i32* [[BIT_CAST]]
; CHECK: return:
; CHECK-NEXT: ret i32* @d2
;
entry:
%0 = icmp ult i32 %cond, 3
br i1 %0, label %switch.lookup, label %return
switch.lookup: ; preds = %entry
%switch.gep = getelementptr inbounds [3 x i32*], [3 x i32*]* @switch.table.internal_linkage, i32 0, i32 %cond
%switch.load = load i32*, i32** %switch.gep, align 8
ret i32* %switch.load
return: ; preds = %entry
ret i32* @d2
}
; ; Relative switch lookup table for strings
define i8* @string_table(i32 %cond) {
; CHECK-LABEL: @string_table(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp ult i32 [[COND:%.*]], 3
; CHECK-NEXT: br i1 [[TMP0]], label [[SWITCH_LOOKUP:%.*]], label [[RETURN:%.*]]
; CHECK: switch.lookup:
; CHECK-NEXT: [[RELTABLE_SHIFT:%.*]] = shl i32 %cond, 2
; CHECK-NEXT: [[RELTABLE_INTRINSIC:%.*]] = call i8* @llvm.load.relative.i32(i8* bitcast ([3 x i32]* @reltable.string_table to i8*), i32 [[RELTABLE_SHIFT]])
; CHECK-NEXT: ret i8* [[RELTABLE_INTRINSIC]]
; CHECK: return:
; CHECK-NEXT: ret i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0)
;
entry:
%0 = icmp ult i32 %cond, 3
br i1 %0, label %switch.lookup, label %return
switch.lookup: ; preds = %entry
%switch.gep = getelementptr inbounds [3 x i8*], [3 x i8*]* @switch.table.string_table, i32 0, i32 %cond
%switch.load = load i8*, i8** %switch.gep, align 8
ret i8* %switch.load
return: ; preds = %entry
ret i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0)
}
; Relative switch lookup table for strings with holes, where holes are filled with relative offset to default values
define i8* @string_table_holes(i32 %cond) {
; CHECK-LABEL: @string_table_holes(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp ult i32 [[COND:%.*]], 4
; CHECK-NEXT: br i1 [[TMP0]], label [[SWITCH_LOOKUP:%.*]], label [[RETURN:%.*]]
; CHECK: switch.lookup:
; CHECK-NEXT: [[RELTABLE_SHIFT:%.*]] = shl i32 [[COND]], 2
; CHECK-NEXT: [[RELTABLE_INTRINSIC:%.*]] = call i8* @llvm.load.relative.i32(i8* bitcast ([4 x i32]* @reltable.string_table_holes to i8*), i32 [[RELTABLE_SHIFT]])
; CHECK-NEXT: ret i8* [[RELTABLE_INTRINSIC]]
; CHECK: return:
; CHECK-NEXT: ret i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0)
;
entry:
%0 = icmp ult i32 %cond, 4
br i1 %0, label %switch.lookup, label %return
switch.lookup: ; preds = %entry
%switch.gep = getelementptr inbounds [4 x i8*], [4 x i8*]* @switch.table.string_table_holes, i32 0, i32 %cond
%switch.load = load i8*, i8** %switch.gep, align 8
ret i8* %switch.load
return: ; preds = %entry
ret i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0)
}
; Single value check
; If there is a lookup table, where each element contains the same value,
; a relative lookup should not be generated
define void @single_value(i32 %cond) {
; CHECK-LABEL: @single_value(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp ult i32 [[COND:%.*]], 3
; CHECK-NEXT: br i1 [[TMP0]], label [[SWITCH_LOOKUP:%.*]], label [[RETURN:%.*]]
; CHECK: switch.lookup:
; CHECK-NEXT: [[RELTABLE_SHIFT:%.*]] = shl i32 [[COND]], 2
; CHECK-NEXT: [[RELTABLE_INTRINSIC:%.*]] = call i8* @llvm.load.relative.i32(i8* bitcast ([3 x i32]* @reltable.single_value to i8*), i32 [[RELTABLE_SHIFT]])
; CHECK: sw.epilog:
; CHECK-NEXT: [[STR1:%.*]] = phi i8* [ getelementptr inbounds ([5 x i8], [5 x i8]* @.str.5, i64 0, i64 0), %entry ], [ getelementptr inbounds ([12 x i8], [12 x i8]* @.str.7, i64 0, i64 0), %switch.lookup ]
; CHECK-NEXT: [[STR2:%.*]] = phi i8* [ getelementptr inbounds ([5 x i8], [5 x i8]* @.str.6, i64 0, i64 0), %entry ], [ [[RELTABLE_INTRINSIC]], [[SWITCH_LOOKUP]] ]
; CHECK-NEXT: ret void
entry:
%0 = icmp ult i32 %cond, 3
br i1 %0, label %switch.lookup, label %sw.epilog
switch.lookup: ; preds = %entry
%switch.gep = getelementptr inbounds [3 x i8*], [3 x i8*]* @switch.table.single_value, i32 0, i32 %cond
%switch.load = load i8*, i8** %switch.gep, align 8
br label %sw.epilog
sw.epilog: ; preds = %switch.lookup, %entry
%str1.0 = phi i8* [ getelementptr inbounds ([5 x i8], [5 x i8]* @.str.5, i64 0, i64 0), %entry ], [ getelementptr inbounds ([12 x i8], [12 x i8]* @.str.7, i64 0, i64 0), %switch.lookup ]
%str2.0 = phi i8* [ getelementptr inbounds ([5 x i8], [5 x i8]* @.str.6, i64 0, i64 0), %entry ], [ %switch.load, %switch.lookup ]
ret void
}
; Relative lookup table generated for a user-defined lookup table
define i8* @user_defined_lookup_table(i32 %cond) {
; CHECK-LABEL: @user_defined_lookup_table(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp sgt i32 [[COND:%.*]], 3
; CHECK-NEXT: br i1 [[TMP0]], label [[SWITCH_LOOKUP:%.*]], label [[RETURN:%.*]]
; CHECK: cond.false:
; CHECK-NEXT: [[IDX_PROM:%.*]] = sext i32 [[COND]] to i64
; CHECK-NEXT: [[RELTABLE_SHIFT:%.*]] = shl i64 [[IDX_PROM]], 2
; CHECK-NEXT: [[RELTABLE_INTRINSIC:%.*]] = call i8* @llvm.load.relative.i64(i8* bitcast ([3 x i32]* @reltable.user_defined_lookup_table to i8*), i64 [[RELTABLE_SHIFT]])
; CHECK-NEXT: br label %cond.end
; CHECK: cond.end:
; CHECK-NEXT: [[COND1:%.*]] = phi i8* [ [[RELTABLE_INTRINSIC]], %cond.false ], [ getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0), %entry ]
; CHECK-NEXT: ret i8* [[COND1]]
;
entry:
%cmp = icmp sgt i32 %cond, 3
br i1 %cmp, label %cond.end, label %cond.false
cond.false: ; preds = %entry
%idxprom = sext i32 %cond to i64
%arrayidx = getelementptr inbounds [3 x i8*], [3 x i8*]* @user_defined_lookup_table.table, i64 0, i64 %idxprom
%0 = load i8*, i8** %arrayidx, align 8, !tbaa !4
br label %cond.end
cond.end: ; preds = %entry, %cond.false
%cond1 = phi i8* [ %0, %cond.false ], [ getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0), %entry ]
ret i8* %cond1
}
[Passes] Fix relative lookup table converter pass This patch fixes the relative table converter pass for the lookup table accesses that are resulted in an instruction sequence, where gep is not immediately followed by a load, such as gep being hoisted outside the loop or another instruction is inserted in between them. The fix inserts the call to load.relative.instrinsic in the original place of load instead of gep. Issue is reported by FreeBSD via https://bugs.freebsd.org/259921. Differential Revision: https://reviews.llvm.org/D115571
2021-12-11 11:14:48 +08:00
; Check to ensure that call @llvm.load.relative is inserted before load, not before gep.
; When a lookup table is accessed inside a loop, and a gep is hosted outside the loop via licm,
; make sure that call @llvm.load.relative is inserted before load.
define i8* @loop_hoist(i32 %x) {
; CHECK-LABEL: @loop_hoist(i32 %x)
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp sgt i32 [[X:%.*]], 1
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds [2 x i8], [2 x i8]* @.str.10, i32 0, i32 0
; CHECK-NEXT: [[RELTABLE_SHIFT:%.*]] = shl i32 [[X:%.*]], 2
; CHECK-NEXT: br i1 [[TMP0]], label %if.done, label %if.false
; CHECK: if.false:
; CHECK-NEXT: [[RELTABLE_INTRINSIC:%.*]] = call i8* @llvm.load.relative.i32(i8* bitcast ([2 x i32]* @reltable.loop_hoist to i8*), i32 [[RELTABLE_SHIFT]])
; CHECK-NEXT: br label %if.done
; CHECK: if.done:
; CHECK-NEXT: [[TMP2:%.*]] = phi i8* [ [[TMP1]], %entry ], [ [[RELTABLE_INTRINSIC]], %if.false ]
; CHECK-NEXT: ret i8* [[TMP2]]
;
entry:
%0 = icmp sgt i32 %x, 1
%1 = getelementptr inbounds [2 x i8], [2 x i8]* @.str.10, i32 0, i32 0
%2 = getelementptr [2 x i8*], [2 x i8*]* @table, i32 0, i32 %x
br i1 %0, label %if.done, label %if.false
if.false:
%3 = load i8*, i8** %2
br label %if.done
if.done:
%4 = phi i8* [ %1, %entry ], [ %3, %if.false ]
ret i8* %4
}
; Another check to ensure that call @llvm.load.relative is inserted before load but not before gep.
; When a lookup table is accessed, and gep is not immediately followed by a load (like if there is a function call
; or an exception in between), make sure that call @llvm.load.relative is inserted before load.
; CHECK-LABEL: @may_not_return()
declare void @may_not_return()
define i8* @gep_is_not_imm_followed_by_load(i32 %x) {
; CHECK-LABEL: @gep_is_not_imm_followed_by_load(i32 %x)
; CHECK: entry:
; CHECK-NEXT: [[RELTABLE_SHIFT:%.*]] = shl i32 [[X:%.*]], 2
; CHECK-NEXT: call void @may_not_return()
; CHECK-NEXT: [[RELTABLE_INTRINSIC:%.*]] = call i8* @llvm.load.relative.i32(i8* bitcast ([2 x i32]* @reltable.gep_is_not_imm_followed_by_load to i8*), i32 [[RELTABLE_SHIFT]])
; CHECK-NEXT: ret i8* [[RELTABLE_INTRINSIC]]
;
entry:
%0 = getelementptr [2 x i8*], [2 x i8*]* @table2, i32 0, i32 %x
call void @may_not_return()
%1 = load i8*, i8** %0
ret i8* %1
}
[Passes] Add relative lookup table converter pass Lookup tables generate non PIC-friendly code, which requires dynamic relocation as described in: https://bugs.llvm.org/show_bug.cgi?id=45244 This patch adds a new pass that converts lookup tables to relative lookup tables to make them PIC-friendly. Differential Revision: https://reviews.llvm.org/D94355
2020-12-30 05:32:13 +08:00
!llvm.module.flags = !{!0, !1}
!0 = !{i32 7, !"PIC Level", i32 2}
!1 = !{i32 1, !"Code Model", i32 1}
!4 = !{!"any pointer", !5, i64 0}
!5 = !{!"omnipotent char", !6, i64 0}
!6 = !{!"Simple C/C++ TBAA"}