We can't get the function name on armv7l, sadly

Author: staticfloat

src/libblastrampoline.c

@@ -22,12 +22,14 @@ int32_t find_symbol_idx(const char * name) {
 // This function un-smuggles our name index from the scratch register it was placed
 // into by the trampoline; We really need this to be the first thing `lbt_default_func_print_error()`
 // calls, so that our temporary register doesn't get clobbered by other code.
-__attribute__((always_inline)) inline unsigned int get_forward_name_idx() {
+__attribute__((always_inline)) inline uintptr_t get_forward_name_idx() {
     uintptr_t idx;
 #if defined(ARCH_aarch64)
     asm("\t mov %0,x17" : "=r"(idx));
 #elif defined(ARCH_arm)
-    asm("\t mov %%r12,%0" : "=r"(idx));
+    // armv7l only has a single volatile register for use, which is already in use
+    // to calculate the jump target, so we can't smuggle the information out. :(
+    return ((uintptr_t)-1);
 #elif defined(ARCH_i686)
     asm("\t mov %%eax,%0" : "=r"(idx));
 #elif defined(ARCH_powerpc64le)

src/trampolines/trampolines_arm.S

@@ -6,15 +6,13 @@
 .cfi_startproc; \
 MANGLE(UNDERSCORE(name))##:; \
     ldr ip, CONCAT(.L,NAMEADDR(name)); \
-    ldr r12,=#SYMBOL_IDX(idx); \
 CONCAT(.L,MANGLE(UNDERSCORE(name))): ;\
     add ip, pc, ip; \
     ldr pc, [ip]; \
     .align 2; \
 CONCAT(.L,NAMEADDR(name))##: ; \
     .word NAMEADDR(name)##-(CONCAT(.L,MANGLE(UNDERSCORE(name))) + 8); \
 .cfi_endproc; \
-.ltorg; \
 
 // Generate both `dgemm_` and `dgemm_64_`
 #include "ilp64_doubling.h"

test/direct.jl

@@ -203,7 +203,11 @@ end
         Base.Libc.flush_cstdio();
     end
     close(io.in)
-    @test chomp(String(read(io))) == "Error: no BLAS/LAPACK library loaded for cblas_sbstobf16()\nError: no BLAS/LAPACK library loaded for cblas_sbstobf1664_()"
+    if Sys.ARCH != :arm
+        @test chomp(String(read(io))) == "Error: no BLAS/LAPACK library loaded for cblas_sbstobf16()\nError: no BLAS/LAPACK library loaded for cblas_sbstobf1664_()"
+    else
+        @test chomp(String(read(io))) == "Error: no BLAS/LAPACK library loaded for (unknown function)\nError: no BLAS/LAPACK library loaded for (unknown function)"
+    end
 
     # Override the default function to keep track of people who try to call uninitialized BLAS functions
     @test lbt_get_default_func(lbt_handle) != C_NULL