10a55caccf
GCC has supported a generic constraint "s" for a long time (since at
least 1992), which references a symbol or label with an optional
constant offset. "i" is a superset that also supports a constant
integer.
GCC's RISC-V port also supports a machine-specific constraint "S",
which cannot be used with a preemptible symbol. (We don't bother to
check preemptibility.) In PIC code, an external symbol is preemptible by
default, making "S" less useful if you want to create an artificial
reference for linker garbage collection, or define sections to hold
symbol addresses:
```
void fun();
// error: impossible constraint in ‘asm’ for riscv64-linux-gnu-gcc -fpie/-fpic
void foo() { asm(".reloc ., BFD_RELOC_NONE, %0" :: "S"(fun)); }
// good even if -fpie/-fpic
void foo() { asm(".reloc ., BFD_RELOC_NONE, %0" :: "s"(fun)); }
```
This patch adds support for "s". Modify https://reviews.llvm.org/D105254
("S") to handle multi-depth GEPs (https://reviews.llvm.org/D61560).
61 lines
2.1 KiB
C
61 lines
2.1 KiB
C
// RUN: %clang_cc1 -triple riscv32 -O2 -emit-llvm %s -o - \
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// RUN: | FileCheck %s
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// RUN: %clang_cc1 -triple riscv64 -O2 -emit-llvm %s -o - \
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// RUN: | FileCheck %s
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// Test RISC-V specific inline assembly constraints.
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void test_I(void) {
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// CHECK-LABEL: define{{.*}} void @test_I()
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// CHECK: call void asm sideeffect "", "I"(i32 2047)
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asm volatile ("" :: "I"(2047));
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// CHECK: call void asm sideeffect "", "I"(i32 -2048)
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asm volatile ("" :: "I"(-2048));
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}
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void test_J(void) {
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// CHECK-LABEL: define{{.*}} void @test_J()
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// CHECK: call void asm sideeffect "", "J"(i32 0)
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asm volatile ("" :: "J"(0));
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}
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void test_K(void) {
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// CHECK-LABEL: define{{.*}} void @test_K()
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// CHECK: call void asm sideeffect "", "K"(i32 31)
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asm volatile ("" :: "K"(31));
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// CHECK: call void asm sideeffect "", "K"(i32 0)
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asm volatile ("" :: "K"(0));
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}
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float f;
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double d;
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void test_f(void) {
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// CHECK-LABEL: define{{.*}} void @test_f()
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// CHECK: [[FLT_ARG:%[a-zA-Z_0-9]+]] = load float, ptr @f
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// CHECK: call void asm sideeffect "", "f"(float [[FLT_ARG]])
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asm volatile ("" :: "f"(f));
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// CHECK: [[FLT_ARG:%[a-zA-Z_0-9]+]] = load double, ptr @d
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// CHECK: call void asm sideeffect "", "f"(double [[FLT_ARG]])
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asm volatile ("" :: "f"(d));
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}
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void test_A(int *p) {
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// CHECK-LABEL: define{{.*}} void @test_A(ptr noundef %p)
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// CHECK: call void asm sideeffect "", "*A"(ptr elementtype(i32) %p)
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asm volatile("" :: "A"(*p));
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}
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extern int var, arr[2][2];
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struct Pair { int a, b; } pair;
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// CHECK-LABEL: test_s(
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// CHECK: call void asm sideeffect "// $0 $1 $2", "s,s,s"(ptr nonnull @var, ptr nonnull getelementptr inbounds ([2 x [2 x i32]], ptr @arr, {{.*}}), ptr nonnull @test_s)
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// CHECK: call void asm sideeffect "// $0", "s"(ptr nonnull getelementptr inbounds (%struct.Pair, ptr @pair, {{.*}}))
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// CHECK: call void asm sideeffect "// $0 $1 $2", "S,S,S"(ptr nonnull @var, ptr nonnull getelementptr inbounds ([2 x [2 x i32]], ptr @arr, {{.*}}), ptr nonnull @test_s)
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void test_s(void) {
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asm("// %0 %1 %2" :: "s"(&var), "s"(&arr[1][1]), "s"(test_s));
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asm("// %0" :: "s"(&pair.b));
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asm("// %0 %1 %2" :: "S"(&var), "S"(&arr[1][1]), "S"(test_s));
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}
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