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| author | Andrew Kelley <andrew@ziglang.org> | 2024-08-01 00:47:05 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-08-01 00:47:05 -0700 |
| commit | 63aa85e7afb37d0b2b5c48309ef1a88d8fd444b5 (patch) | |
| tree | 65ae842b0bc28adfa9e81eda7dcde46c753501f6 | |
| parent | 8ea323822ba1fc2f54940841b2cedb3494230a3c (diff) | |
| parent | 653eb7535514d06aca1eaaf777f82e1ecd968086 (diff) | |
| download | zig-63aa85e7afb37d0b2b5c48309ef1a88d8fd444b5.tar.gz zig-63aa85e7afb37d0b2b5c48309ef1a88d8fd444b5.zip | |
Merge pull request #20872 from alexrp/riscv-gp
start: Initialize `gp` to `__global_pointer$` on riscv.
| -rw-r--r-- | lib/std/start.zig | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/lib/std/start.zig b/lib/std/start.zig index 61e41370b4..512cc8d4bd 100644 --- a/lib/std/start.zig +++ b/lib/std/start.zig @@ -272,13 +272,27 @@ fn _start() callconv(.Naked) noreturn { \\ bstrins.d $sp, $zero, 3, 0 \\ b %[posixCallMainAndExit] , + // zig fmt: off .riscv32, .riscv64 => + // The self-hosted riscv64 backend is not able to assemble this yet. + if (builtin.zig_backend != .stage2_riscv64) + // The RISC-V ELF ABI assumes that `gp` is set to the value of `__global_pointer$` at + // startup in order for GP relaxation to work, even in static builds. + \\ .weak __global_pointer$ + \\ .hidden __global_pointer$ + \\ .option push + \\ .option norelax + \\ lla gp, __global_pointer$ + \\ .option pop + else "" + ++ \\ li s0, 0 \\ li ra, 0 \\ mv a0, sp \\ andi sp, sp, -16 \\ tail %[posixCallMainAndExit]@plt , + // zig fmt: off .m68k => // Note that the - 8 is needed because pc in the jsr instruction points into the middle // of the jsr instruction. (The lea is 6 bytes, the jsr is 4 bytes.) @@ -293,6 +307,7 @@ fn _start() callconv(.Naked) noreturn { \\ .gpword . \\ .gpword %[posixCallMainAndExit] \\ 1: + // The `gp` register on MIPS serves a similar purpose to `r2` (ToC pointer) on PPC64. \\ lw $gp, 0($ra) \\ subu $gp, $ra, $gp \\ lw $25, 4($ra) @@ -314,8 +329,6 @@ fn _start() callconv(.Naked) noreturn { \\ .gpdword %[posixCallMainAndExit] \\ 1: // The `gp` register on MIPS serves a similar purpose to `r2` (ToC pointer) on PPC64. - // We need to set it up in order for dynamically-linked / position-independent code to - // work. \\ ld $gp, 0($ra) \\ dsubu $gp, $ra, $gp \\ ld $25, 8($ra) |