[AArch64] Add Tiny Code Model for AArch64
This adds the plumbing for the Tiny code model for the AArch64 backend. This,
instead of loading addresses through the normal ADRP;ADD pair used in the Small
model, uses a single ADR. The 21 bit range of an ADR means that the code and
its statically defined symbols need to be within 1MB of each other.
This makes it mostly interesting for embedded applications where we want to fit
as much as we can in as small a space as possible.
Differential Revision: https://reviews.llvm.org/D49673
llvm-svn: 340397
diff --git a/llvm/test/CodeGen/AArch64/code-model-tiny-abs.ll b/llvm/test/CodeGen/AArch64/code-model-tiny-abs.ll
new file mode 100644
index 0000000..bd09cf7
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/code-model-tiny-abs.ll
@@ -0,0 +1,54 @@
+; RUN: llc -mtriple=aarch64-none-eabi -code-model=tiny < %s | FileCheck %s
+
+@var8 = global i8 0
+@var16 = global i16 0
+@var32 = global i32 0
+@var64 = global i64 0
+
+define i8* @global_addr() {
+; CHECK-LABEL: global_addr:
+ ret i8* @var8
+ ; The adr calculation should end up returned directly in x0.
+; CHECK: adr x0, var8
+; CHECK-NEXT: ret
+}
+
+define i8 @global_i8() {
+; CHECK-LABEL: global_i8:
+ %val = load i8, i8* @var8
+ ret i8 %val
+; CHECK: adr x[[ADDR_REG:[0-9]+]], var8
+; CHECK: ldrb w0, [x[[ADDR_REG]]]
+}
+
+define i16 @global_i16() {
+; CHECK-LABEL: global_i16:
+ %val = load i16, i16* @var16
+ ret i16 %val
+; CHECK: adr x[[ADDR_REG:[0-9]+]], var16
+; CHECK: ldrh w0, [x[[ADDR_REG]]]
+}
+
+define i32 @global_i32() {
+; CHECK-LABEL: global_i32:
+ %val = load i32, i32* @var32
+ ret i32 %val
+; CHECK: adr x[[ADDR_REG:[0-9]+]], var32
+; CHECK: ldr w0, [x[[ADDR_REG]]]
+}
+
+define i64 @global_i64() {
+; CHECK-LABEL: global_i64:
+ %val = load i64, i64* @var64
+ ret i64 %val
+; CHECK: adr x[[ADDR_REG:[0-9]+]], var64
+; CHECK: ldr x0, [x[[ADDR_REG]]]
+}
+
+define <2 x i64> @constpool() {
+; CHECK-LABEL: constpool:
+ ret <2 x i64> <i64 123456789, i64 987654321100>
+
+; CHECK: adr x[[ADDR_REG:[0-9]+]], {{.LCPI[0-9]+_[0-9]+}}
+; CHECK: ldr q0, [x[[ADDR_REG]]]
+}